# Cutting Foam Board



## LeonardS (Mar 13, 2012)

I purchased a 4' x 8' sheet of 2" thick Dow Corning Foam Board. What is the best way to cut this foam to get a nice edge? I am going to place this under the telescoping cover and above the inner cover on each of my hives.


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## jmgi (Jan 15, 2009)

Because of the thickness its hard to get a straight square cut doing it with a long sharp knife like I do, but I don't see why you couldn't cut it on a table saw to get a better cut, or maybe a hand held jigsaw or circular saw. John


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## twgreen3 (Aug 22, 2008)

I use a hot wire. An electric fence wire and battery charger work good. This may not be worth it if you just have a little to do. Table saw does work also just not as clean of an edge.


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## RiodeLobo (Oct 11, 2010)

Table saw works great, fast and easy.


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## mgolden (Oct 26, 2011)

Table saw with a carbide tipped finishing blade makes a very clean cut. 

Keep your hand on the piece next the fence, cause the blade can catch it and make a nasty gaouge in it.


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## BeeCurious (Aug 7, 2007)

LeonardS,

t:

How deep is the edge of your covers?


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## LeonardS (Mar 13, 2012)

The telescoping covers are the Mann Lake units. Probably about a 2" edge. I am going to place the insulation on the inner cover, then wrap the hive with 15 lb. felt/tar paper and fold it over the top of the foam. Then I will place the telescoping cover over that.


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## LeonardS (Mar 13, 2012)

We had a home builder in the office and he suggested a circular saw with the blade installed backwards.


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## crofter (May 5, 2011)

Caution advised! You really need to control both pieces and preferable use a splitter. I had a chunk suck onto the blade of a table saw and pieces shattered and flew all over. You would not think the blade could get hold of it so!


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## libhart (Apr 22, 2010)

My POS jigsaw won't cut a square edge on wood worth a darn but it goes through EPS board like butter.

If you're cutting a lot of it though, want a nice edge, don't have a saw already, then here's the way to go that doesn't require storage space. This is the cheap version mind you 
http://www.harborfreight.com/130-watt-heavy-duty-hot-knife-66182.html


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## billybwf (Aug 17, 2012)

LeonardS said:


> We had a home builder in the office and he suggested a circular saw with the blade installed backwards.


The blade backwards on a saw is how we cut vinyl and other softer material so it does not break.


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## westernbeekeeper (May 2, 2012)

I used my table saw for the exact same application and it worked fabulously.


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## ByGonzah (Feb 4, 2012)

What are you using as a moisture board?


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## Capricorn (Apr 20, 2009)

Last year I used a hand held jigsaw. Worked nice, clean cut. Somewhat messy, but better then the other method I tried, which was a utility knife. I haven't tried a table saw.


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## Adrian Quiney WI (Sep 14, 2007)

I cut some a week or two ago with a cheap handsaw from Home Depot. It was a lot easier than what I tried last year with a big knife. Also I noticed that the foam was scored at 16 and 32 inches in the long direction which made things even easier.
http://s1110.photobucket.com/albums/h456/AdrianQuineyWI/?action=view&current=2012-09-02141818.jpg


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## LeonardS (Mar 13, 2012)

ByGonzah said:


> What are you using as a moisture board?


No moisture board, but I will have an upper entrance in the candy board to let out humidity.


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## blueribboncookies (Jun 5, 2011)

We cut A LOT of this type of insulation when we built our house. 
1. Use a long metal straight edge and a carpet knife with a SHARP/NEW blade. 
2. Score the insulation as deeply as you can. 
3. Place your sheet of insulation so your weight is on the main part of the sheet.
4. Let the part you want to remove hang over the edge of something - a saw horse, a table edge, etc.
5. Use a 2x4 to put pressure on the edge you want to remove until it breaks along the score.
Ta dah!

PS - We didn't have luck with a table saw or a circular saw - too dangerous, too.


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## Acebird (Mar 17, 2011)

Utility knife or a carpet knife will work as described but it is a broken edge. This edge could be squared off by using a sanding block with coarse sandpaper. This is a bit messy.
As mentioned before a hot wire does make the best cut because it seals the edge. Getting the current in the wire and the wire feet rate takes a little practice to get the best cut.

When I was building cardboard airplanes I cut a lot of this foam for the ribs of the wings and actually built a pentagraph for the application. I was lucky enough to get my hands on some nitenel wire for the cutting blade which is an exotic metal that worked perfect.


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## crofter (May 5, 2011)

Most online RC hobby supply places will have it. Inconel is commonly used but you probably could get away with stainless steel as you would not need a long length exposed. I have cut wing cores for RC planes as Acebird mentions and was cutting 30 inches deep so the inconel can be stretched tighter in that case. The wire needs to be somewhat shy of visibly red so you have to play with resistances and power supply depending on your wire size.

I have cut lots of foam on the table saw and sure got a surprise when I got violent results. Thanks Blueribboncookies. I will still cut it on the table saw but not without a long splitter to be certain neither the sheet or the off cut can move sideways against the side of the blade.


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## Keth Comollo (Nov 4, 2011)

Table saw works perfectly.


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## Matt F (Oct 7, 2014)

you guys are making this too complicated. Get one of those disposable box cutters - the ones where you break off sections of the blade and slide the blade out farther. Slide 3" of blade out and score the foam as deep as you can, then snap it off.


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## Acebird (Mar 17, 2011)

Matt F said:


> you guys are making this too complicated. Get one of those disposable box cutters - the ones where you break off sections of the blade and slide the blade out farther. Slide 3" of blade out and score the foam as deep as you can, then snap it off.


You can always cut the board about 1/8 big and then clamp a straight edge on both sides of the foam so you can slice it to perfect size with a sharp carving knife. Foam slices very easy when the waste piece is thin. It doesn't grab a thick knife.


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## llgoddj (Apr 11, 2012)

There have been many options, but have not heard what I use. Depends on how much cutting you need to do, but I take a hacksaw blade, without the handle, just the blade. First I draw the lines using a Sharpie pen, black so it shows easily. then just take the hacksaw blade in your hand and cut halfway down through the board on your first cut. On your second pass cut all the way through the board. It gets as close to a perfect cut as possible without a big mess.

I have used this method many times to perfection.

good luck!!!


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## PAHunter62 (Jan 26, 2011)

+1 table saw


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## MTN-Bees (Jan 27, 2014)

I used a DeWalt 18 volt circular saw and it worked fine. In the future I may try a finishing blade. I used the circular saw so I could do the cutting outside.


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## Michael Bush (Aug 2, 2002)

A utility knife works fine but if you want a more perfect edge, a table saw with a plywood blade in backwards could work. Here's some styrofoam cutters:
http://www.amazon.com/Woodland-Scenics-Wire-Foam-Cutter/dp/B0006KSMEU
http://www.dickblick.com/itemgroups-s/styrofoamcutters/


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## Michael B (Feb 6, 2010)

I find myself using my Kreg Jig for my circular saw more and more for cutting paneled products.

https://www.kregtool.com/store/c48/saw-attachments/p79/rip-cuttrade/


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## Tim KS (May 9, 2014)

Acebird said:


> When I was building cardboard airplanes I cut a lot of this foam for the ribs of the wings and actually built a pentagraph for the application. I was lucky enough to get my hands on some nitenel wire for the cutting blade which is an exotic metal that worked perfect.


Geeez, and I thought I was the only one who was so cheap to build giant sized R/C planes out of cardboard with foam ribs. :thumbsup:


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## cg3 (Jan 16, 2011)

We use a table saw with it's regular blade, but what a mess. Fine, clingy, foamboard dust everywhere.


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## My-smokepole (Apr 14, 2008)

I used a heavy break away blade knife blade all the way out. Two or three passes with a straight edge.


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## Acebird (Mar 17, 2011)

Tim KS said:


> Geeez, and I thought I was the only one who was so cheap to build giant sized R/C planes out of cardboard with foam ribs. :thumbsup:


I would like to see some pics.

here is some of mine.
http://i697.photobucket.com/albums/vv333/acebird1/pic002_zpscd18f0aa.jpg
http://i697.photobucket.com/albums/vv333/acebird1/Owner_and_Plane_zpse7870276.jpg
http://i697.photobucket.com/albums/vv333/acebird1/StartCheapo01_zpsb34782a1.jpg


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## jredburn (Feb 25, 2012)

Band saw if you have one.


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## whiskers (Aug 28, 2011)

Some of the kick-backs described above may have happened because the material melted and then stuck to the side of the blade. Splitter suggestion is good, I would avoid finishing blades that cut narrow kerfs compared to the thickness of the blade. Keep feed speed up to avoid the same material sitting by the blade (and heating up) for a long time. Use push sticks so your hands are never alongside the blade.

Be safe-
Bill


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## Tim KS (May 9, 2014)

Acebird said:


> I would like to see some pics.


A few of mine....

http://photos.imageevent.com/tstolz/timsmodelplanes/websize/MVC-186F.JPG
http://photos.imageevent.com/tstolz/timsmodelplanes/websize/MVC-190F.JPG
http://photos.imageevent.com/tstolz/timsmodelplanes/websize/MVC-188F.JPG


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## Acebird (Mar 17, 2011)

nicely done.


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## whiskers (Aug 28, 2011)

With a camera and some sort of downlink you two guys could bring a new dimension to bee lining.

Nice work, build one a little bigger and take me for a ride.

Bill


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## Acebird (Mar 17, 2011)

whiskers said:


> With a camera and some sort of downlink you two guys could bring a new dimension to bee lining.
> 
> Nice work, build one a little bigger and take me for a ride.
> 
> Bill


Best done with a heli type device and electrically powered. Like the new drones at Griffiss. Very much done today in the aerial photography hobby. It is a way to spend thousands on a hobby.


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## Phoebee (Jan 29, 2014)

I've used several of these methods.

I used to have an old Hirsch saw table, designed to mount Skil saws and saber saws. I rigged it with a hot wire on an arm so that it worked like a jigsaw. Worked a treat on the pink foam sheets, but tended to stink. I powered the hot wire with a step down transformer on a Variac transformer, being as I'm the kind of guy who has this stuff.

I use a table saw to cut it on occasion. With a sharp blade and slow feed it gives a reasonable cut.

Most often I use a sharp knife, not serrated. A little water on the blade may help it cut without dragging. If I want to clean up the cut I may put it on my bench belt sander.


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## lakebilly (Aug 3, 2009)

Tablesaw for sure. WEAR A MASK!!


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## Acebird (Mar 17, 2011)

Phoebee said:


> If I want to clean up the cut I may put it on my bench belt sander.


Yes, sanding is another method I forgot but it is a pain getting the dust off because of the static. This is one of those things where it is helpful to dedicate a belt sander and mount it vertical to a bench with a table and then rig up a shop vac for the dust. You can also do the same using a motor and a disc. Use very coarse sand paper and it won't melt the foam. You can also rip off 1/8 in no time flat.

http://i697.photobucket.com/albums/vv333/acebird1/DSCF7260_zps0c965613.jpg


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## lakebilly (Aug 3, 2009)

sanding Dowboard? is this a piano? ;-)


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## Khild (Mar 1, 2014)

If you have a hack saw take the blade out and use it. 32 teeth per inch works best. Blade wont get dull and in makes a clean cut.


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## Acebird (Mar 17, 2011)

lakebilly said:


> sanding Dowboard? is this a piano? ;-)


If you were going to make bee boxes you would need square cuts to exact size for gluing. In most cases perfect cuts are not necessary but some of us are OCD.


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