# plywood box



## dixiebooks (Jun 21, 2010)

I use plywood for nucs using the Coates plan. Don't know that I would use it for regular 10-frame hives. If I did I would be careful not to get bit, particularly if they are rabid.  -james


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## n1rcv (Dec 8, 2010)

Check the glue one the cdx plywood. If it is "Exposure 1" it is not intended for long term outdoor use. Plywood with "Exterior" glue is intended for outdoor used.


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## Specialkayme (Sep 4, 2005)

I don't know much about plywood, but isn't the "X" in "CDX" supposed to mean "Exterior" glue is used?


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## Rader Sidetrack (Nov 30, 2011)

Specialkayme said:


> I don't know much about plywood, but isn't the "X" in "CDX" supposed to mean "Exterior" glue is used?


A variety of wood industry sources say that the "X" in CDX refers to "Exposure 1" rating.

The info below is from Rosboro, a plywood producer in central Oregon.



> *Q: What is the difference between Exterior and Exposure 1?*
> 
> A: Exterior plywood has a fully waterproof bond and is designed for applications subject to exposure to the weather or to moisture for its entire service life. Exposure 1 plywood has a fully waterproof bond and is designed for applications where construction delays may be expected prior to providing protection.
> 
> ...


Here is the link to their website if you want more info:
http://www.rosboro.com/index.php?action=about.faq

Essentially, the glue in CDX is the same glue in "exterior" rated plywood, but the two panels are NOT the same when it comes to outdoor exposure.


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## Specialkayme (Sep 4, 2005)

I stand corrected.

So would CC be the true 'exterior' rated plywood?


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## Rader Sidetrack (Nov 30, 2011)

Plywood should have a grade stamp on each sheet, similar to those below. (You may need to click the image to enlarge it.) Note the word "Exterior" on the one on the right. The others only say "Exposure 1".








Here is the source of the image above:
http://www.aecinfo.com/1/resourcefile/00/22/61/apa04.htm

If you want Exterior rated plywood, look for the grade stamp to be sure. "C-C" may be the most economical exterior rated grade, but it may also be that not _all_ "C-C" is exterior rated.


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## Velbert (Mar 19, 2006)

If you are having to buy plywood to build hives with i would rather us 1x12 dressed lumber, now if you have some that was give to you i might build a few out of Necessity if i was short of money. I like to build them but i stoped building my own because the boughten ones with the dove tail are more stronger well worth the little extra


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## BoilerJim (Apr 15, 2011)

I would be concerned about the chemicals used in Exterior plywood that makes it weather resistant. That is a reason we don't paint the inside of our hives due to the chemicals that leach into the honey and the bees themselves.


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## windfall (Dec 8, 2010)

Actually the adhesive used for exterior glue (phenol formaldehyde) outgass far less formaldehyde than the cheaper resins (urea formaldehyde) used on many interior applications. This of course assumes the manufacturer has properly mixed and cured the adhesive... not always the case.


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## Daniel Y (Sep 12, 2011)

Exterior ply is not treated with chemicals. Also notice that the attachment above states that Exterior ply has a bond intended to withstand exposure only for delays in construction. it is still expected to be covered and protected. Marine Ply will hold up to exposure for the long term. The others will separate fairly quickly. If you paint it to protect it paint the edges also.


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## windfall (Dec 8, 2010)

Marine ply also uses phenol-formaldehyde. It is waterproof and will stand up to the navy "boil test", same as "exterior" ply.
The main difference in marine ply is that it is supposed to be guaranteed "no voids". Depending on the grade stamp marine ply will also have limited number of patches, differing species used in the core lamination, different grade veneers in core, ect.


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## SunnyBee (Oct 21, 2011)

I was only talking about 3/4" ext. ply wood. I do not think the plywood will efect the bees or honey. We use glue on the frames and boxes with no problum. Price is my only reason to think about using plywood. At $20.00 for cdx , yes that is ext. plywood, and $32.00 for BC, a more finished serfice ext. plywood, and getting 5 deeps and 1 med box, would makes it $4.00-$6.00 per box. To buy mann lake budget grade deep would be $11.00 ea. It would cost more than that to make your own from 1x12 . My question was more along the line of how do they hold up if primed and 2 coats of paint. I do have another thought, it will be heaver with plywood. 
For those that have or do use 3/4" plywood for there boxes, how does it hold up?


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## windfall (Dec 8, 2010)

I don't know if plywood bothers/hurts the bees.

Glue used on frames and corner joints is usually aliphatic resin (wood glue) which is a very different product than those used to laminate plys. 

New (recently laminated ply) outgass at a much higher rate than 1 year old. But testing has revealed the big variable to be in quality control by manufacturer. some panels dump a lot, some very little.

I do know that formaldehyde is a known carcinogen as well as having a number of other toxic effects in humans. But people live a lot longer than bees, and our houses are often poorly vented (in winter at least) allowing levels to get quite high depending what you let come inside your home.


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## SunnyBee (Oct 21, 2011)

For those that have or do use 3/4" plywood for there boxes, how does it hold up?


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## fish_stix (May 17, 2009)

We use 1/2" CDX for all our lids. Lasts a long time if painted! We also have a bunch of nucs we built with 3/4" CDX. They have lasted a long time too and I see no deterioration in them. You can expect any type of plywood to warp more than lumber but it will be usable for a very long time. Sometimes we get a bow in the nuc sides (plywood) but that just makes the lid tighter.


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## RiodeLobo (Oct 11, 2010)

fish_stix said:


> We use 1/2" CDX for all our lids. Lasts a long time if painted!


 Do you have issues with bowing and subsequent robbing? I have some plywood lids and had a terrible time with yellow jackets through the bowed spaces.


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## rwurster (Oct 30, 2010)

I use plywood solid bottom boards and plywood top boards with no issues. Both sides and the edges are painted. There can be some warping in the summer when I shim the top cover to make large top entrances but then again there's 4 bricks holding it down. A few shims in the center of the top cover keep warping to a minimum. Then its swapped out as a bottom board when I remove the sbb. I've only had 1 robbing incident and it was due to me fixing some cross combing in one hive, but I was there when it started and all I had to do was add more shims to reduce their entrance. It confused the foragers but they figured it out by the next day.


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## peacekeeperapiaries (Jun 23, 2009)

RiodeLobo said:


> Do you have issues with bowing and subsequent robbing? I have some plywood lids and had a terrible time with yellow jackets through the bowed spaces.


Answering for FISH (My Dad) we run telescoping lids...so the 1x2's solve the bowing prob. We also bring lids back into the shop each year or two in rotation to repaint them, makes them last longer in our harsh sunshine and copious amounts of rain and humidity, plus we write on our lids to keep "notes" on each hive so it covers our chicken scratch.


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## Joseph Clemens (Feb 12, 2005)

I make many 5-frame medium nucs using my personal mods to the plans posted by D. Coates. I use 15/32" plywood, I just buy the cheapest with the most ply layers. I haven't had any problems with any of those I've built, yet. I haven't even painted any of them, but if I were to notice any problems develop that might be related to their being exposed, I'd simply prime and paint them, that should be enough to protect them from the elements.


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## BMAC (Jun 23, 2009)

Joe how much rain and how often do you get rain in your area? 

I would think warping would become an issue depending on how long they stay wet and so on. I know the 3/4" plywood I buy for my pallets are generally warped when I get it from CHEAPO DEPOT. Last year I decided to use dry ply and it is simply flatter than the other JUNK they sell for plywood. The only plywood I ever seen really hold up outside for bee equipment is Marine Plywood. Boy that stuff has quite the sticker shock. I have some for lids and never worry about warping or anything else.


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## Joseph Clemens (Feb 12, 2005)

It doesn't rain here very often, but it does rain some and the outside surfaces of everything outdoors does get wet. I use thick polystyrene for both bottom boards and covers for almost all of my nucs. I use pieces of old towels covered with pieces of 3 mil black plastic for inner covers on my nucs (the plastic keeps the towels protected from being wetted by the rain). I also have painted the outsides of many of my hives and nucs, just not any of these 15/32" plywood nucs, yet. I've had more warping of the solid lumber in hives and nucs than I have seen from any of the plywood equipment, so far (it's been very stable). I have a few pieces of equipment made from 3/4" plywood, and it has warped much more than equipment made of 15/32" plywood.


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