Bowtie_Bob
Active member
Hello everyone, I have some 4x8 sheets of 3 inch paper backed foam board insulation and I am trying to find a good way to cut them neat and easy to install in my garage walls. Thanks your any ideas you can give
foamboard insulation
- Thread starter Bowtie_Bob
- Start date
wnstwolf
Well-known member
I used something similar to clad my ceiling with. Best thing I found to easily make clean cuts was a long utility blade. I have some Sears cutters that use 4" replacement blades. The shers are no good for this but take the blade only and it was perfect. Replacment blades ar around 6 bucks for 3 pack.
Dan in Pasadena
Well-known member
Doesn't a table saw cut it cleanly? I'm sure it'll throw around insulation dust and you'll need a mask (or respirator)plus shop vac.
JCfreak
Well-known member
Table saw. Circular saw and straight edge. Hand saw and straight edge.
kelpaso1
MEMBER EMERITUS
Electric turkey carving knife.
over40pirate
Well-known member
- Joined
- Aug 31, 2012
- Messages
- 160
That's my vote also.
Steelhorse27
Well-known member
Would a hot wire "knife" work?
7echo
Well-known member
We cut a lot of blue and pink foam with hot wire cutters. Works great for curvy organic shapes.
Table saw works great, though you may have to flip it to cut all the way through, same with a circular saw and fence, as previous posters mentioned.
One thing to consider is spray foaming the inside corners of the wall cavity to seal the studs to the exterior sheeting and glue the foam board to the wall.
JCfreak
Well-known member
Hot knife is clean but slow.
plott hound
Well-known member
- Joined
- Apr 19, 2014
- Messages
- 114
i used my cordless Makita circular saw to cut my board.did a nice clean job.
Autorotica
Well-known member
Using a table saw to cut mine...
Chris
Chris
fury9
Well-known member
Yup, cordless skilsaw works nice.
OP
Bowtie_Bob
Active member
Thanks everyone for the ideas, I may try the circular saw that seems like it might work.
rburke65
Well-known member
I had 2 1/4"..... 2 1/2" thick 4'x8 sheets of styro foam that I used to stuff my stud cavities and truss cavities and I made a hot wire cutter to cut the panels. Didn't have all the 'white balls' all over. Worked great!
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I used a regular hand saw to cut 3" pink foam board in the Home Depot parking lot. 4x8 sheets did not fit in my vehicle and I planned ahead to what size I needed to cut it to. It cuts very easily. Somewhere I have a photo of then 12 year old son cutting some.
I have an old serrated steak knife that I use.
EXACTLY. The point is it's so easy to cut you need not bother with the power tools. Electric carving knives are great for cutting the type of foam used in upholstery. They are overkill for foam board.
depends on what you're cutting (length of cut). all foams are different but typically your rigid foams do well with a hot knife or razor knife. a nice clean cut can be had by either, not sure about a table saw or circular saw. got a feeling the teeth are too aggressive and a wide kerf once you take into consideration the tear out.
worked for a place that did prefab foam insulated steel panels, that's all i did was mess with foam all day long. not the paper backed panels, just huge sheets of generic styrofoam type foam. cut bevels for windows, door frames, squared edges, sanded the panels flat prepping for stucco sealer.
the cheapy dollar type utility knives with the snap off blades work good because you can extend the blade out to get through 3-4" thick material. using a straight edge and applying very slight force to bow the blade you can get it to hug the straight edge.
never used a small diy hot knife so those may not work all that great. used one around 12ft long, was a two person job and like anything else there's a knack to it. can't go too fast, go too slow and it burns and wallows out the edges. done right it leaves a hair line through the foam and the heat melts and seals the edges just like a factory edge (vs the crumbly edge typically achieved by scoring/snapping).
if it was softer foam i'd opt for a turkey carving knife (like poly foam). hot knives won't work so well with foam cushion. good luck.
worked for a place that did prefab foam insulated steel panels, that's all i did was mess with foam all day long. not the paper backed panels, just huge sheets of generic styrofoam type foam. cut bevels for windows, door frames, squared edges, sanded the panels flat prepping for stucco sealer.
the cheapy dollar type utility knives with the snap off blades work good because you can extend the blade out to get through 3-4" thick material. using a straight edge and applying very slight force to bow the blade you can get it to hug the straight edge.
never used a small diy hot knife so those may not work all that great. used one around 12ft long, was a two person job and like anything else there's a knack to it. can't go too fast, go too slow and it burns and wallows out the edges. done right it leaves a hair line through the foam and the heat melts and seals the edges just like a factory edge (vs the crumbly edge typically achieved by scoring/snapping).
if it was softer foam i'd opt for a turkey carving knife (like poly foam). hot knives won't work so well with foam cushion. good luck.