# Oxalic Acid Vaporization temperature



## Scitfrostbite

I tried making my own. It worked for one treatment. Many others have experimented with homemade designs too but all too often they don't work well. After all of my tinkering I ended up purchasing a real vaporizer. I would recommend buying one. Although high front end cost, only cost pennies to treat so much cheaper in the long run. My vaporizer paid for itself in one yr.


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## Artur_M

I keep bees as an hobby and have only 2 hives. My current treatment is oxalic acid dribbling method, so it still cheap.
I just think that OAV is more effective, thats why I want to make one.


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## Rader Sidetrack

According to the CDC, oxalic acid Sublimation temperature is 157° C (314.6°F) and the "Melting point (decomposes) of oxalic acid is 189.5°C (373°F). Here is the link: http://www.cdc.gov/niosh/ipcsneng/neng0529.html


>> I am thinking to build one using wood burning iron.

That could be a real challenge if you mean an electric "wood burning iron". Typical models available seem to be in the 25-30 watt range. Commercial vaporizers (those take about 3 minutes per dose) are in the 150 watt range. So a typical wood burning iron will be severely under-powered.

Many of the "build your own" electric vaporizers at Beesource revolve around using a diesel engine "glow plug" that expects 12 volts or so from a battery, and draws 12-13 amps (about 150 watts).


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## Artur_M

The power has not much meaning in current technology life.

Here on in Michael's store http://www.michaels.com/walnut-holl...r-detailer/10353141.html#q=Woodburner&start=2 .


> *It heats to 750° F*


 - so I am not sure if it would be enough.
I found the other wood burner earlier which was going up to 950F and had a temperature regulator.

The commercial might have higher power, cause it heats fast, but might burn fast to if you keep it on for more then directed time (say in manual it says 2 min, but you keep it on for 5 min and your $$$ gone - not good.)

I am sure there is a way to build it very easy and very cheap.


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## exmar

I use the dribble method as I can't justify the cost of the vaporizer units. If you look around youtube, there are videos of various "plumbing" coupled with a propane torch to heat the OA which is then directed via a 1/2" thin wall copper tube into the hive. Seems too easy, a 1/2" compression fitting with female threads, add a screw on pipe cap and it's done. Don't see too much about it, so I wonder if it has some fatal error? e.g. The torch gets the OA too hot, incomplete vaporization, or other chemical factors. All the commercial and "glow plug in machined aluminum" home built units the activity takes place in the hive and not externally.


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## Artur_M

I've seen that video with torch and a pipe - too much trouble.
Electric one is much easier and I want one for 110V. My hives are in my yard next to my house and I don't want to buy a 12v battery for OAV.


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## Rader Sidetrack

Artur_M said:


> The power has not much meaning in current technology life.
> 
> Here on in Michael's store ...


The wood burner you linked is 16.5 watts. Use whatever old/new technology you like - 17 watts is not going to be enough to vaporize a meaningful amount of oxalic acid to treat a colony.


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## DerTiefster

Automotive technology is an area where things are done as cheaply as practical. Glow plugs make great heaters, are designed to run for years in automotive engines, and should run nearly forever in mild service.

Power is important because there is a dwell time you want to keep low inside the hive. You don't want to heat the whole interior up to 120F while getting the OA vaporizer up to OA vaporization temps. The size of the pan puts a lower bound on the convective heat load from air. You want to overcome the heat capacity of the whole hot mess and get it up to temp in a short time. I didn't do the computational homework, but I suspect the heater is most of the mass and you simply have to pour enough power in to get things warm enough in a couple of minutes. A minimum time / minimum mass design would involve tearing your toaster apart to repurpose some Nichrome, but you'd have to cover it to keep the OA away from the filament. Messy project. Much cleaner to use an existing design or a glow plug. Designs are available on the web if you have a slug of appropriate metal and a drillpress and some other tools.

I bought mine.


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## dynemd

16.5 watts is not enough. You going to need about 200-300 watts to vaporize efficiently. That's what all the commercial one use.


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## whiskers

Here is a page that has physical properties of OA.
http://webbook.nist.gov/cgi/cbook.cgi?ID=C144627&Mask=4#Thermo-Phase
The molecular weight of OA is about 90 so a mole of OA weighs 90 grams. (Everything in round numbers).

In order to vaporize something you must first raise it to the temperature where it begins to vaporize, and then add heat (at constant temperature) in an amount called the enthalpy of vaporization. For OA about 97000 Joules/mole. So 97000Joules/mole / 90 gm/mole (again round numbers) 1000 joules/gm.

A watt is 1 joule per second so in a perfect world the 15 watt wood burner should vaporize the gram of acid in a little over a minute, but it's not a perfect world, the bought, or built, vaporizers take a couple of minutes to vaporize a 3 or 4 gram dose and they have 150 watt heaters. Indicating a lot of heat lost to the surroundings. It is likely that your little iron will not even be able to maintain the pan at the vaporization temperature. If it can, prepare to spend a lot of time at each hive.

On the positive side, perhaps a bigger heater can be made to work, think perhaps a large soldering iron, expensive new but you never know what the next garage sale might yield. 
Bill


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## Delta 21

I tried an old 45 watt 110vAC soldering iron but couldnt produce enough heat with it. 

I settled on the "crack pipe" method. - 3/8" brass 90 deg elbow with a brass plug in one end. Fitting in the other end connecting 12"of 1/4" copper tube. Insert in the hive and cover the entrance. Propane torch setting on a 4x4 directing the flame to the bulk of the brass for 3 minutes. Dont set the bee yard on fire!! :no: . Leave the hive entrance covered for 10 more minutes. Savogran wood bleach from Ace hardware.

Less than $25 for the whole set up. (i already had the torch) and it works adequately. At least until my kids buy me the only vaporizer on the market that will fit inside a hive entrance slightly less than 1/2" tall. Yep, I want/need the Cadillac model  because its only 3/8" tall. (Its always something!)

I test fired it till I knew how it was going to react, fashioned a wind break to keep the flame steady, learned that you need to clean out the copper tube, especially where it bends, after every use. I can treat my backyard hives in less than a half hour from start to finish. Its 18 today with wind chill in the single digits. Looking for the warm December dayI can hopefully get a good broodless treatment done. :thumbsup:

If your gonna do OA Vapor, GET A RESPIRATOR. Any further warnings will include laughter and ridicule.


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## stan.vick

I made one out of a d c beverage heater I inserted a copper plumbing cap inside the coils, all for just a few bucks. My sister later gave me a regular OAV setup, I use both, think I use my home made one the most. The home made one heated up too fast and too hot so I added fifty feet of # 18 wire, turned out to be perfect temp. and now I don't have to move my truck as often when treating.


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## Artur_M

I am browsing eBay to see what is available as a vaporizer - they are 25-40W.

So, what is the truth? Did someone measure the temperature of he vaporizer when it is hottest?

I believe temperature matters more than power.


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## Rader Sidetrack

Artur_M said:


> I believe temperature matters more than power.


The temperature of the hottest part of a candle flame is about 2500 degrees F. 

So, why is it that trying to heat a home in a Maryland winter - _with a single candle_ - is going to result in one _COLD_ house? :lookout:


The answer is that BTUs actually _DO_ matter. And BTUs (can also be mathematically converted to watts) are a measure of how "powerful" a heat source is. A 40 watt vaporizer (available on Ebay) is underpowered, and will make a poor vaporizer.


But hey. its _your_ money ...


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## Artur_M

I had enough philosophy in my life - someone can keep a little for himself.

There is an answer to how hot the heater gets.
I believe the question is straight forward, so the answer should be.


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## DerTiefster

Artur,
What Rader is getting at is that there is a "thermal mass" that the heater has to warm up. It might be that the heater can push 1 gram to some temperature, but when that 1 gram (oxalic acid, for instance) is held up by 20 grams of stainless steel, one has to heat the steel along with the acid. The heater might not be up to the task. But as Rader also says, "It's your money." He's right. Do what you want.

But you might find it interesting to get an optical thermometer (also called a pyrometer) and measure the temperature in that non-contact way both empty and with a bit of OA in it. It might work.


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## Artur_M

We can continue night of philosophy long thinking of some other things like how warm the weather should be so the vaporizer should warm up surrounding air and so on ... and be as rude as Rader, who is "Moderator" btw, but the bottom line is: the vaporization starts when the acid reaches to the certain temperature.

The question is about temperature.
How to reach that temperature is totally different problem.

Respects and regards.


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## Rader Sidetrack

Artur, I posted in post #2 of this thread a reference for the temperature that needs to be reached to vaporize oxalic acid.

One way or another, your home-made or purchased vaporizer needs to heat up enough to get that oxalic acid + the cup/dish/container that holds the oxalic acid to the vaporization temperature. In the course of that heating process, some heat will be lost to the surrounding air. And the _closer_ that the device gets to the vaporization temperature, the rate of heat loss will _increase_. Your design will need to overcome those obstacles before it even _starts_ to vaporize the oxalic acid.

A number of posts in this thread have tried different approaches to try get that point across, including the one by member _whiskers_ in post #11 that covers some of the mathematics of the situation.

The way I look at Beesource threads and posts is that they are an enduring resource. Which means that to the practical extent possible, _someone_ should post a correction to misleading or wrong information that may be in a particular post in that thread. Thermodynamics involving thermal mass, surface area and heat lost to the surrounding air may be complicated, but it is an "objective" situation ( i.e. this kind of math is possible to calculate) rather than subjective where each individual can have a different opinion (i.e. 'green is the best color').

A 20-40 watt electric heater is very unlikely to make a suitable oxalic acid vaporizer. I can appreciate that some may not like to hear that, but its true, and I believe that the majority of readers of this thread would rather have _useful_ info rather than "ya, sure, you betcha".


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## johno

Artur m, this is not a case of discussing philosophy, it is of discussing physics and some of the laws of physics and these laws are written in stone and cannot be changed by an act of congress. So one must realize that to move a certain mass of some materiel through a degree in temperature is going to require a certain quantity of heat and when you have increased it sufficiently to boil of the water of crystallization and then to sublimation you have to increase the amount of heat perhaps by a hundred times to provide the latent heat required for a change of state of the OA. So at this point I would state that 100watts is the minimum power required to do the job for what its worth.
Johno


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## Artur_M

Rider,

It's not my place to teach you curtesy and politeness, but look at your own words: 


Rader Sidetrack said:


> So, why is it that trying to heat a home in a Maryland winter - _with a single candle_ - is going to result in one _COLD_ house? :lookout:


You can have your own opinion and things can work one way for a long time.

Till 1960-1970 cars were going 10mpg, but look now days, and I believe the efficiency can be raised some more.

Also, there is a "law of energy conservation", in which people didn't believe for a while.

Again, this can become to a long and boring conversation.

I'll try to built one and will keep you posted with whatever results I found.

Money are spent for several projects and there is no warranty the results are pleasing - and that's OK.


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## Rader Sidetrack

Perhaps my point got lost behind the smileys. Read back through this thread keeping this in mind ...

Its not the _temperature_ of the heat source that is relevant. _It is the BTUs / watts that the heater puts out that is relevant._ They are not the same thing. 

[hr] [/hr]
Experimention is great. :thumbsup::thumbsup:

If you want an electric vaporizer, a $10 glow plug is perfectly suitable to make your own vaporizer. There are a variety of how-to threads on doing so. But in the end, you will need a source of 12 volts at about 13 amps to run this kind of vaporizer. Inexpensive materials, some tools, and some ingenuity is required.

There are a few options for making a 110 volt vaporizer. I've seen one that uses an inexpensive heating coil meant for heating up a cup or so of water. Inexpensive materials, some tools, and some ingenuity is required. The potential risk of personal injury is somewhat higher with this approach.

The so called "crack pipe" method of heating with a propane torch is another alternative. Inexpensive materials, some tools, and some ingenuity is required. Again there are multiple threads on this approach.

Still, it is important to have enough BTUs or watts heating the device to make it work. Temperature is a _goal_, _not_ a means to achieve the goal. 




... and if you don't like my use of smileys, well, that's not going to change. :gh:


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## Geno

> The answer is that BTUs actually _DO_ matter. And BTUs (can also be mathematically converted to watts) are a measure of how "powerful" a heat source is. A 40 watt vaporizer (available on Ebay) is underpowered, and will make a poor vaporizer.
> 
> 
> 
> 👍
Click to expand...


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## FlowerPlanter

When I did do OAV for a short time I made a vaporizer similar to this one;

https://www.youtube.com/watch?v=ALHz4B1vqKo

Either a glow plug or crack pipe you're basically doing the same thing. I don't think it's possible to get the temp high enough, quick enough using either methods to damage the OA before it evaporates. 

IMO the best way to treat if from the top, you can see exactly what is going on, I believe it is now SNL preferred method (I may have played a part in this)


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## costigaj

A good OXAVAP OAV wand costs less than two 10 packs of Apivar.


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## Lburou

My first impression of vaporizers was that I'd make one. When I studied the DIY models in vogue, I realized they would likely be hit or miss in terms of the temperatures they generated. 

DIY Vaporizor temperatures below 157C or above 190C will be ineffective for killing mites. 950 F is too hot and a waste of your time & money. Unless you can assemble a device that produces temperatures in the target range for the necessary length of time, you are going to go through the motions of OAV treatments and your bees are going to die anyway. You won't save any money, and it will cost you the additional cost of more bees if you stay in beekeeping. JMO


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## Arnie

Artur,
What you need is the ability to heat a metal vessel that holds a minimum of about one or two teaspoons to approximately 450 degrees F and hold it at around 400degrees F for 30 seconds or so. That's what the vaporizers like the Sublimox do. 

Or, you need a heat source that can heat a piece of metal holding about a teaspoon or more volume up to 450 or 500 degrees in a couple to three, four minutes. The wand vaporizers do that. My Hielesyer goes almost to 600 degrees in 45 seconds or so.

The heat gun style vaporizers heat a larger volume of say, 2 tablespoons to 1/4 cup or more upwards of 400 degrees and maintain that temp indefinitely. 

I've seen video of someone using a tea light candle to vaporize a couple grams of OA. I wouldn't want a lit candle in any of my hives, but hey, to each his own.

The problem you will encounter with your wood burner is achieving and maintaining the temperature in a vessel big enough to hold 2 grams of OA with enough room for boil over. Can you attach that wood burner to a copper or aluminum cup and have the cup get to 450 degrees and then hold at least 400 degrees for 30 to 45 seconds? 
Or, can you put in the OA and have the wood burner heat the container to 450 degrees in a reasonable amount of time? 

Those are the challenges.


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## FlowerPlanter

Use a temp gun on your DIY vaporizer, you will not be able to get the temp from 157C to 190C before 1-3 gr of OA is gone. Similar to way water boils in a pot, it will not get above 100C (at 1 atm) no matter how hard you try.


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## johno

In the end I think we should look at an old proverb, " You can take a horse to water but you can't make it drink "
Johno


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## crofter

Here is a question that may have a tested and proven answer but may not be so readily available. The warning about the decomposition point of vaporized oxalic acid and whether it *could* happen in the tray type evaporators has been thrashed and trashed inconclusively it seems.

Put that question aside and look at *what might be the results if it did occur* in any of the vaporizer designs. 

Supposedly if a high enough temperature is reached by the vapor it will decompose into other sub components like formic acid, water vapor and carbon dioxide and monoxide. _Would these sub components recombine to oxalic acid vapor immediately when they re cool below the decomposition point?_ or do they remain separate? Does it even matter? 

If the boil off of the water of hydration in the initial heating is very rapid such as in a high heat input device, would the steam, produced concurrently with the OA vaporization, affect the desirable form of the oxalic acid vapor. In other words is it desirable to input heat slowly enough that the dehydration of the Oxalic Acid Dihydrate, can mostly complete before the vaporization of the Oxalic Acid Monohydrate occurs?

Are we perhaps giving up something in effectiveness by striving merely to "go off quick"?


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## dudelt

Artur, 
You may be able to get the pan holding your OA up to the right temperature using a soldering iron or some other contraption on the cheap. However, Rader is correct that the amount of BTU's does matter. If the home made vaporizer requires you to leave it in the hive for 20 minutes while it is heating up, is it really worth the money you saved? your time is worth something too. The bottom line is, you need the pan to get heated QUICKLY. The longer you leave the hot pan in the hive, the more bees will die, the greater the chance you have of frying the queen, and the greater chance of setting the hive on fire (it has happened). My opinion is that you will be far happier buying the vaporizer or continuing with the trickle method. The vaporizer you buy will last years and you will only pay for it once.


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## Arnie

crofter said:


> Are we perhaps giving up something in effectiveness by striving merely to "go off quick"?


This is a good question. It is something to ask the folks in Europe who use the Sublimox. 
Also, I am using the Lega on some of our hives; that does the same thing.....vaporize while the OA is still boiling (at least the first few hives).

I will know more next spring when I see how the Lega-ized hives come through winter. I'll let you know on thread Hex started.


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## crofter

Thanks Arnie; :thumbsup:

I look forward to your report next spring. It seems some designs do need a bit of operator input to hit the sweet spot of effectiveness. Testing effectiveness with reasonable control is a lot more time consuming than doing the treatments. So often we have so many wild cards in play it makes it difficult to know exactly what is responsible for results we see. Good record keeping sure is not my _forte_


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## johno

I can only talk from experience about the supposed breakdown of OA when subjected to higher temperatures and can only say that when using a paper particulate mask and adding 2 grams of OA to a heated chamber at about 500F the reaction that produces a vapor plume where the glittering of OA crystals may be seen without any hint of FA vapor coming through the paper mask suggests to me that the OA cannot reach the temperature required to break it down to any of the other gasses due to the latent heat required for the OA to change its state from solid to vapor and this can be seen by the rapid drop of temperature into the 330F range until the sublimation is complete and where the temperature will rapidly rise to the set point value.
Johno


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## crofter

Johno are you seeing any indication that would indicate the difference in demand for the change of state of the water of hydration vs the latent heat for the phase change of the oxalic acid or are both operations occurring virtually on top of each other. On viewing the process from a cold start on a tray type heated with a single glow plug ~ 150 watts consumption there seems to be two separate phases. 

I have been tossing my 2 gm dose into my tray with only enough cooling between hives so there is not _furious_ action when it hits the pan. I am curious about whether there would be any negatives in effectiveness if you toss the charge in when the pan is "smoking" hot. My low mite levels and not doing counts on every hive would not have been very conclusive.


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## johno

Crofter the copper vessel has been closed while I have been doing tests and the vapor has been exiting through the tube designed to go into the hive so I have not seen the result of adding OA into a heated vessel. If I had left the top off I doubt whether I would have been able to see anything anyway because of the vapor coming straight out, However when I have removed the top prematurely you are able to see liquid bubbling against the walls and producing vapor. Now the composition of the vapor could contain H2O and OA crystals but as I have said not a whiff of FA. I have 5 gals of FA so believe me when I tell you what its vapor smells like. The vapor I have seen glittering in the sunlight has been the vapor exiting the small tube. I have no doubt that so far that vapor is OA and the only question I have is if the vapor is successfully coating the inside of the hive bodies. I will try to check this out in future tests. So in conclusion it is my opinion that when inserting OA into a pre heated vessel some boiling off the water of crystallization and some sublimation of the OA takes place simultaneously until the OA sublimation is completed. Again these are my personal unscientific observations and due to this litigious environment I am not responsible for anyone who now goes and does anything silly with OA
Johno


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## crofter

Thanks, johno;

I have been looking at video of some of the commercially available units quite similar. There seems to be no qualms about dumping the charge in and immediately starting the treatment.


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## Broadeye

Wow! Lotta discussion over something so simple. Lotta people like the commercial (hot plate) vaporizer 'cause it's easy to use, and pretty safe. But, for those of us who like do-it-yourselfing, the so-called crack pipe is a lot less complicated to make than discussed in this thread. All you need is a copper stubend (a nine inch long, half inch id copper pipe with a closed end). Cost about $4. You make an open top, 2 inch or so deep open-top box with a plexiglas (sealed with duck tape) top You drill a hole in one side to fit the copper tube. You vaporize from the top of the hive. You put the OA in the tube, insert the tube thru the hole, and gently heat it with a propane torch. First, you'll see water vapor exit the tube. Then you'll see a denser emission of OA. Of course, be careful not to gas yourself. You might have to press down on the box to minimize OA escape. Note: Regardless of whether you're using a hot plate vaporizer from the bottom or this crack pipe from the top, what enters the hive is not vapor. It is a fume, i.e., a mist of very fine OA particulate. From the top, the fume settles onto the comb as it sinks. From the bottom, it does the same thing as it rises convectively into the hive. either way, it probably doesn'tg go all gthe far into the hive. I presume it de-mites the bees as they run around trying to clean up the precipitated OA.


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## sjj

johno said:


> ... However when I have removed the top prematurely you are able to see liquid bubbling against the walls and producing vapor. ...


There are two sources of water. 

1. Water of decrystallization of oxalic acid dihydrate.
2. Water of dehydration: 
Heat causes formic acid to decompose to carbon monoxide (CO) and water. 

You can not smell formic acid. You can not smell carbon monoxide either. 
But you can see boiling water. And crystals. 
Carbon monoxide harms the bees. 
It is definitively unwanted in the process.


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## johno

sjj, I can certainly smell the formic acid that I use and I believe you will smell large amounts of CO probably not any from such a small quantity of OA, but again with the small source of heat electrical vaporizers use I believe you are not able to heat to the OA to where it can decompose due to the latent heat required to boil and sublimate.
Johno


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## stan.vick

A follow up on my earlier post, I made my vaporizer from a "D.C." ( 12 volt ) beverage warmer, not a 110 volt one. I adjusted the temperature needed to vaporize the OA without getting too hot, by adding to the length of electrical wire between my twelve volt truck battery and the home made vaporizer, the longer and thinner the wire the less power arriving at the vaporizer. After adjusting the wires I found that fifty feet of #18 wire is perfect to get the proper vaporizing temperature, it may be different with a different type of beverage warmer. Sorry I can't give you the scientific equations on this method, I'll leave that to the gurus.


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## crofter

I would not agree that formic acid has no smell! If some of the oxalic acid was being broken down into the other substances the risk from this may not be as much an issue as lost effectiveness of the Oxalic acid in the finely divided crystalline form that affects the mites.

I see no one has taken a shot at the question of whether the driven off water, and any possible decomposition products, will recombine as they cool down below the decomposition temperature. Such products of decomposition may exist in only a transient state and pose no issues to what we are wanting to accomplish on the mites. 

Granted if such decomposition products were held at or above the decomposition temperature (375 F.) they would be a problem. That temperature by itself if it were only air, would be ~ 3 times higher than deadly to the bees, but that obviously would not be considered parameters for mite treatment.


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## Forgiven

I kind of wonder if sjj swapped formic there instead of oxalic by accident. Formic really smells, and comes into the post out of nowhere anyways


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## RudyT

A bit off topic but I think relevant...another solution to cost is to buy a good vaporizer (and maybe a battery/charger) to be shared among several users, or even club members. That gets the cost down to a tolerable level. I bought one and am glad to loan it out. Even self-interest will do, as fewer varroa mites in the neighborhood is good for my bees.


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## Artur_M

RudyT said:


> A bit off topic but I think relevant...another solution to cost is to buy a good vaporizer (and maybe a battery/charger) to be shared among several users, or even club members. That gets the cost down to a tolerable level. I bought one and am glad to loan it out. Even self-interest will do, as fewer varroa mites in the neighborhood is good for my bees.


Agree :thumbsup:

The bee club here, that I am not a member of, I headed that there is a centrifuge that beekeepers share, but it so busy at the season, so some of the club members bought one for themselves.

I agree, that membership fee should not be only for "get together" discussion, but also to support club members with advise and necessary equipment and so on.

This all look like socialism  and it's not good  the vaporizer dealers should have a job and tremendous sales margins, otherwise they will be out of business.

It can be my own impression, but I found so many "lobbyists" for commercial made vaporizers, which are sold for more than $100 with cost of making those under $10. This is how capitalism works 
Don't believe me? watch some of the "Shark Tank" shows, you'll find the profit margins.


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## dudelt

Artur, 
I am so sorry that you feel it is wrong to make a profit but nobody is getting rich selling vaporizers. There is just way to much competition among the different vendor. There are lots of plans to make your own here on Beesource and all over the internet as well. Better yet, build a better one yourself and go on Shark Tank with your million dollar idea. There is a reason there are "lobbyists" for the different vaporizers. Because they work! If you don't like the price, make it yourself. Better yet, start a company that rents out vaporizers by the day. It is your life, make your own decisions. Now is the time to stop talking about it and get to work doing something.


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## johno

Artur M, many have been trying to explain to you the laws of physics, now we will need to explain some of the realities of economics. First if I spend $10 on materiel and spend 3 or 4 hours to build myself a vaporizer the cost to me remains $10. Now if I was to sell the same product and had an employee take 3 hours at what most young folks would want is a minimum of $15 per hour now the vaporizer would cost the $10 plus $45 and then the govt. would want another $7. So we are already up to $62 now I have purchased the materiel hired the worker designed the product surely you would not begrudge me from a little profit in the enterprise say about 20% so that's about another $12.50 so you can come and collect the goods for about $74.50 but you don't want to collect so I must ship maybe UPS so that's another $10 at least so now we are up to $84.50 Now you say but I can build the thing for $10 and you rip off artists want to charge me nearly $85 what a bunch of capitalist pigs Anyhow that is the way things go except I doubt anyone would be charging $15 for hourly labor more like $50 per hour. So the moral of the story is make it yourself or don't complain about the price if you purchase one.
Johno


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## Artur_M

dudelt said:


> Better yet, start a company that rents out vaporizers by the day. I


Thanks for the idea.



johno said:


> Artur M, many have been trying to explain to you the laws of physics, now we will need to explain some of the realities of economics. First if I spend $10 on materiel and spend 3 or 4 hours to build myself a vaporizer the cost to me remains $10. Now if I was to sell the same product and had an employee take 3 hours at what most young folks would want is a minimum of $15 per hour now the vaporizer would cost the $10 plus $45 and then the govt. would want another $7. So we are already up to $62 now I have purchased the materiel hired the worker designed the product surely you would not begrudge me from a little profit in the enterprise say about 20% so that's about another $12.50 so you can come and collect the goods for about $74.50 but you don't want to collect so I must ship maybe UPS so that's another $10 at least so now we are up to $84.50 Now you say but I can build the thing for $10 and you rip off artists want to charge me nearly $85 what a bunch of capitalist pigs Anyhow that is the way things go except I doubt anyone would be charging $15 for hourly labor more like $50 per hour. So the moral of the story is make it yourself or don't complain about the price if you purchase one.
> Johno


john, I am sure your math is correct, but ... there is a big BUT
There are always guys who work for way cheap, like $15/week or even better $15/month.
UPS charges $10 for shipment - China international post charges $1 for shipment

Good luck with your high prices.
I am sure you make $$$'$$$/year, so you can light your cigar using $100 bill.

PS: by laws of physics, I am sure you have conventional light bulbs in your house:applause::applause:.


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## beemandan

Always cool when someone asks for information....and complains and argues because he's unhappy with the opinions. Why is everyone...anyone...still bothering?


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## johno

Artur M,I did not just get off some banana boat from somewhere, I have posted articles on Bee Source detailing how you can build a vaporizer for about $10, And I mentioned that I was not interested in manufacturing anything. So there you are you can look up all the articles on how to do it yourself but you would rather just complain about how much it would cost you to purchase one already made for you. and you really need to study some basic engineering and you will find that watts in energy and equal to watts when you are talking about LED or fluorescent lighting are not the same thing. If they were the same you would be using the new bulbs for incubator heating and then find that the new bulbs do not generate enough for heating. But after a while I think that I am wasting my time, It is no good giving a dead patient medicine.
Johno


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## tpope

beemandan said:


> Always cool when someone asks for information....and complains and argues because he's unhappy with the opinions. Why is everyone...anyone...still bothering?


hmmmmmm... me thinks you could be right!


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## Artur_M

To ALL who are undermining my intelligence:

The original question was about temperature and till now I didn't receive that number either in C or F. There is only one reference from Rader to CDC web site which does not have info about vaporization temperature.
All the talk here goes about the power need to be applied. How and using what materials to build the vaporizer - there wasn't a question about that.

It is pretty obvious that certain amount of energy has to be applied to reach to the certain temperature.
Am I going to heat-up a cup or a pan - let me decide that.
Am I going to heat-up 1gr of acid or 50gr - let me decide that.

Thank you!!!


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## Arnie

I gave you the temps in post #27 for the various types of vaporizers. This is not scientific theory; it is temps those devices actually achieve. 
The Sublimox is set to 230 degrees C, (447F). Vaporizes in 30 seconds.
The pan vaporizers such as Heilesyer go upward of 500 degrees. Takes about a minute to a minute and a half to vaporize.


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## Artur_M

Arnie said:


> I gave you the temps in post #27 for the various types of vaporizers. This is not scientific theory; it is temps those devices actually achieve.
> The Sublimox is set to 230 degrees C, (447F). Vaporizes in 30 seconds.
> The pan vaporizers such as Heilesyer go upward of 500 degrees. Takes about a minute to a minute and a half to vaporize.


Sorry,
It probably got lost in the middle of this nuisance.

Thank you.


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## Rader Sidetrack

Artur_M said:


> The original question was about temperature and till now I didn't receive that number either in C or F. There is only one reference from Rader to CDC web site which does not have info about vaporization temperature.


Well, the temperature at which oxalic acid vaporizes is 157° C (314.6°F), as I posted and linked earlier in post #4 of this thread. 

In terms of oxalic acid, sublimation is used by some to describe vaporization. 


> Sublimation has also been used as a generic term to describe a solid-to-gas transition (sublimation) followed by a gas-to-solid transition (deposition).[3]
> 
> https://en.wikipedia.org/wiki/Sublimation_(phase_transition)


It doesn't matter whether you call it _sublimation_ or _vaporization_, the temperature at which the phase change in oxalic acid occurs is 157° C (314.6°F).


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## Artur_M

PHYSICAL 
PROPERTIES 

*Sublimation point: 157°C 
Melting point (decomposes): 189.5°C* 
Relative density (water = 1): 1.9 

Sounds a little strange - somehow the vaporization point is lower than melting point?


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## Rader Sidetrack

The decompostition point is where the oxalic acid (if it gets heated that high) breaks down into formic acid (plus other components). That is _not desirable_ for purpose of vaporizing varroa.


However, one of the _benefits_:thumbsup::thumbsup: of a 40 watt vaporizer design is that there will be _no worries_ about it getting hot enough to decompose the oxalic acid and produce formic acid! :lpf:


.


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## snl

Rader Sidetrack said:


> The decomposition point is where the oxalic acid (if it gets heated that high) breaks down into formic acid (plus other components). That is _not desirable_ for purpose of vaporizing varroa.


True, but fortunately the decomposition into other elements that occurs to if OA is heated too hot, too fast from a gram or two is not enough to harm the bees. The resulting plum of vapor from from decomposition looks just like a good OA vaporization but there is no OA in that plum to kill VM. The only way (other than an expensive lab test) to know whether the vaporizer you're using (if other than a "store" bought unit that's been tested) works, is to try it then follow up by looking for the mite kill on a sticky board.


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## crofter

Would decomposition occur when the gas form is heated beyond the 380F. (?) temperature. The gas is hard to heat (in an open tray) beyond the sublimation temperature as it is quite easy for it to move off into surrounding air. Different story though when the gas is being conveyed in a much higher temperature air stream. The quite contained vessels with only a small exit provide for a large radiant surface which the oxalic gas is exposed to. They are structurally quite different than the open tray designs in regard to surface area.

I think snl is correct in saying that the amount of any products of (possible?) decomposition are not a direct danger to the bees but notable only for the amount they would reduce the volume of the desired OA gas and subsequent OA microcrystals deposited in the hive.

It is reported that effectiveness is not greatly reduced with a smaller dose or increased by a larger dose. Mortality margins are not extremely affected either by upping the recommended dose but that is not a direction I think we should be complacent with.


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## Arnie

snl said:


> True, but fortunately the decomposition into other elements that occurs to if OA is heated too hot, too fast from a gram or two is not enough to harm the bees. The resulting plum of vapor from from decomposition looks just like a good OA vaporization but there is no OA in that plum to kill VM. The only way (other than an expensive lab test) to know whether the vaporizer you're using (if other than a "store" bought unit that's been tested) works, is to try it then follow up by looking for the mite kill on a sticky board.


Question:
You are familiar with the Sublimox style vaporizers. They operate above the commonly accepted temperature limit for decomposition of OA into formic acid. 
Has anyone tested those to determine if they do indeed produce formic acid?

I'm beginning to have my doubts about the temperature data I read re the breakdown of OA.


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## snl

Arnie said:


> Question:
> You are familiar with the Sublimox style vaporizers. They operate above the commonly accepted temperature limit for decomposition of OA into formic acid.
> Has anyone tested those to determine if they do indeed produce formic acid?


Yes, I sell a Sublimox Style Vaporizer. The only testing I've done is to look at the results of my and others vaporizations (on sticky boards).... the mite drops are comparable to the that of the Varrox. I have my doubts on temperature also but the results are indisputable. The commercial VM vaporizer works on high temps as well with great results as reported by those who use them. There is more at play here than meets the eye.


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## Richard Cryberg

Artur_M said:


> PHYSICAL
> PROPERTIES
> 
> *Sublimation point: 157°C
> Melting point (decomposes): 189.5°C*
> Relative density (water = 1): 1.9
> 
> Sounds a little strange - somehow the vaporization point is lower than melting point?


What is strange? Does not sound a bit strange to me. In fact sounds perfectly normal to me. Sublimation happens all the time with all solids that have a finite vapor pressure which includes most chemicals. Ever see dry ice melt? You probably better stick to rubbing two sticks together so you do not hurt yourself. You stand little chance of making or using an OA vaporizer without a resulting trip the emergency ward. OA vapor is dangerous stuff if not handled properly and you sure do not have the skills to handle it properly based on your lack of general knowledge.


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## crofter

Arnie said:


> Question:
> You are familiar with the Sublimox style vaporizers. They operate above the commonly accepted temperature limit for decomposition of OA into formic acid.
> Has anyone tested those to determine if they do indeed produce formic acid?
> 
> I'm beginning to have my doubts about the temperature data I read re the breakdown of OA.


Temperatures at the boundary between heating surface and product are pretty tricky. Theycan vary greatly in a very short distance an in extremely short time duration. I think we are all familiar with hearing a pot "sing". This cavitation occurring under liquid that is not boiling is actually flash steam formation and collapsing. Momentary and minute areas and volumes here can exceed boiling temperatures. Over a period of time, solutions can char! This is not something I pulled out of my hat. With really large heat inputs surface temperature differentials, boundary layers of product can reach quite a high temperature.

One thing I am in the dark about is whether the products of oxalic gas decomposition can recombine on cooling or is it a one way process. This question does have some implications in the question of how important the possible decomposition issue might be.


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## Richard Cryberg

crofter said:


> One thing I am in the dark about is whether the products of oxalic gas decomposition can recombine on cooling or is it a one way process. This question does have some implications in the question of how important the possible decomposition issue might be.


OA thermal decomposition is irreversible.


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## snl

crofter said:


> One thing I am in the dark about is whether the products of oxalic gas decomposition can recombine on cooling or is it a one way process. This question does have some implications in the question of how important the possible decomposition issue might be.


We can go on and on about all this and some will..... But as far as beekeeping and mites are concerned, what you see on your sticky board after vaporizing is all you really need to know.......


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## johno

snl is quite correct that it is the result that matters, something to be considered in obtaining these results would be the time needed to complete the treatments if you have to do many hives and the coverage of the OA crystals within the hive. I would h guess that some treatments that do not show good results would be due to poor coverage inside of the hive space and would consider a little positive pressure with the OA vapor might help this. Just a random thought.
Johno


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## crofter

snl said:


> We can go on and on about all this and some will..... But as far as beekeeping and mites are concerned, what you see on your sticky board after vaporizing is all you really need to know.......


Sounds a bit dismissive...... 

Personally, I like to know the why of what is happening (or not happening). I certainly have no misgivings about the safety or effectiveness of the tray type evaporators. My consideration is length of time involved. I felt there is a bit of shortage on knowledge on the implications of new devices that speed up the dosing time from 3 or 4 minutes to less than a minute. Maybe the newer devices are no compromise at all; I think that is by far the most likely scenario.


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## snl

crofter said:


> I felt there is a bit of shortage on knowledge on the implications of new devices that speed up the dosing time from 3 or 4 minutes to less than a minute. Maybe the newer devices are no compromise at all; I think that is by far the most likely scenario.


Really? The great feedback on the very quick (seconds) VM vaporizer should possibly alleviate your concern (s)....


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## johno

That last quote from snl requires some consideration, There have been problems with dosage per hive and efficacy due to the systems being too hot or too cold with both the VM and Lega vaporizers mostly due to the operators learning curve, so those vaporizers require more operator skill than some of the simpler types. The wand has been great to get OA treatments going but has had the drawback of time and of labor to remove entrance reducers and such. There was also the possibility of a fried queen here or there so the quest for a better mouse trap will always persist. I would like to get to the stage where I get my 2 grams of OA vaporized into a hive quickly and efficiently then walk away knowing that the job is done and I do not have to worry about whether the OA has covered the inside of the hive completely.
Johno


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## Artur_M

Again, we are off the track.

So, Rader and everybody are you suggesting that for vaporizing OA *the goal is* to heat it up to Sublimation point: *157°C ?*??
This is the core question.

How much mass do you need to heat up - the bigger the more power you should apply.
Equipment wise: everybody can support one or the other brand. Leaving all the other arguments - the same producer has limits of quality about 5%, so 2 identical things of the same producer are not the same.
Besides that, the test should take place at different weather condition, different air quality and more and more.

I like sedan car, but there are times that I wish I had a track o even a box-track, but it is not what I like to drive every day.
Some people like pick-up track, if not say more, they have to have a track - so, there is no ONE best for everyone, but there is one goal for everyone = easy interesting life 

Good luck to all


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## clyderoad

Artur_M said:


> Again, we are off the track.


so it's been 9 days of one-up-man-ship here , have you made one yet?
let's see it!
if not, why not? plenty of info over the years from those who have made their own.


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## Artur_M

clyderoad said:


> so it's been 9 days of one-up-man-ship here , have you made one yet?
> let's see it!
> if not, why not? plenty of info over the years from those who have made their own.


clyder, even if I built one today, I don't need to tell you that it won't be effective, cause it is 20F outside and I won't be able to test it.
Be reasonable.

FYI - I am looking for appropriate parts.


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## clyderoad

you might have to make some of those appropriate parts.
what's the plan? still a wood burning tool? or... something else now that you have additional information about
what's necessary and why?

you'll get some warm days to test, that's for sure. don't let that stop you.


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## beemandan

It is time to dig. People have told you what they thought....and, evidently it isn't enough. Why do you require someone to deliver the information?


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## Artur_M

clyderoad said:


> you might have to make some of those appropriate parts.
> what's the plan? still a wood burning tool? or... something else now that you have additional information about
> what's necessary and why?
> 
> you'll get some warm days to test, that's for sure. don't let that stop you.


Let me put it this way - it is NOT my first priority.

I am not telling you what to do, so be nice and don't tell me what to do.
Christmass is coming - be nice and kind, otherwise Santa will not bring present for you :lpf:


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## clyderoad

Artur_M said:


> Let me put it this way - it is NOT my first priority.
> 
> I am not telling you what to do, so be nice and don't tell me what to do.
> Christmass is coming - be nice and kind, otherwise Santa will not bring present for you :lpf:



the best thing for you, and many of us, would be for Santa to bring you a ready made vaporizer.
sounds like you may hurt yourself trying to reinvent this wheel.


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## Arnie

Oy Vey!!


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## svarog

oxalic acid
258 F or 126 C in liquid form
323 F or 162 C maximum temperature
354 F or 179 C carbon dioxide + formic acid dangerous
363 F or 184 C carbon monoxide + formic acid is very dangerous
When heating oxalic acid you need to know for this temperature.
Mandatory protection dur- ing fan operation with oxalic acid.
Oxalic acid evaporation should not be done when the bees in the winter in ball.
Use only when the great invasion of varroa.
Once in a year when there are no larvae.
Believe me that I paid the school.


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## sjj

Rader Sidetrack said:


> The wood burner you linked is 16.5 watts. Use whatever old/new technology you like - 17 watts is not going to be enough to vaporize a meaningful amount of oxalic acid to treat a colony.


There is someone, who did the OAV with a STW60NE10 transistor as the heating element.


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## Rader Sidetrack

sjj said:


> There is someone, who did the OAV with a STW60NE10 transistor as the heating element.


Well, the STW60NE10 is rated at 100 Volt 60 Amps according to this spec sheet available at Mouser Electronics:
http://www.mouser.com/ProductDetail/STMicroelectronics/STW60NE10/?qs=Zmg/77r1i5regFWZ12xayQ==

That means the STW60NE10 is capable of a _*lot*_ more BTU output than a 16.5 watt wood burner.


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## Artur_M

Hello and Merry Christmas (even to those who didn't support me)!!!

Today is 64F here and I decided to get to my project. I built it :wiener: and tested it - it works 

I put 1.3gr oxalic acid in the cup and turned the burner on - didn't keep time, but it took about 2 min.

Had a little problem with spilling and residue appearing on top edges, but at the end it burned all.

Here is the picture of it:







I will try to attach a cup with bigger bottom and more shallow (3/4" cup) This one is 1/2" cup and 1.3-1.5gr oxalic acid barely fit in it.


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## Arnie

Cool.
I hope it works well for you.


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## Artur_M

:update:

Todays day was warm enough (54F outside) to do another experiment with 3/4" cup and it was successful as well :banana:

Here are pictures: 






,






,








The vaporization went well, got some residues on sides inside, but the residues melt again and got vaporized at the end.
It took me about 2 minutes to get the 1g oxalic acid melt + 2-3 minutes to have the cup dry to finish whole process. I believe for hobbyist it's an ok time, not mentioning that it cost me under $10  

Cost:
1. Wood burner from Michaels - $7.50
Original price $15, with 50% coupon = $7.50
2. 3/4" cup from Home Depot $1.20
3. 1/2" screw $0.99 (I didn't have correct screw, so I had to buy puck of 10 for $0.99)


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