Help please: cutting styrofoam sheets

[Bill Gill]

Well, I don't see where any one else has mentioned it, so do what I did. I used my Harbor Freight Multifunction Tool. That's the Fein MultiMaster knock off. You should be able to find a coupon to get it for $35. It does a great job and is available for a great many other jobs, since it really is a multifunction tool. It makes a little fine dust but there isn't any massive clean up required after you finish with the door.

By the way. You will probably need to cut each of the insert pieces in 2 so they will fit inside the channels around the side of the door panels. I suggest that you cut them on an approximate 45 degree angle. That way you can slip one half in, then the other and they will fit without having to be forced.

Bill

[willshak]

Zz Yzx wrote the following:

I have a steel exterior door that faces the sun for most of the day and it never gets much warmer than the air temperature. It is painted white. As for the insulation, how about attaching it to the interior of the panels? Cover the whole panel rather than just the recesses. I have two 8' wooden paneled garage doors under a 4' overhang that never get any sun on them. I glued 1/2" styrofoam pieces into the recessed panels on the back of the door, but that was for a little more winter insulation.

[Bennett Price]

[Joe]

Table saw works fine with any decently sharp blade. Did two 16' square rooms a while back with 1 1/2" 4 x 8 foam board (green) sliced to 16" wide to go between furring strips. Table saw has the standard Delta dust collector, no mess in the shop. Cut edges were perfectly flat and clean. The cut went about as fast as could be fed through the blade, maybe took 10 seconds. For round access holes, the hole saw did well enough. Based on that seems any sharp toothed cutting tool ought to work fine.

Joe

[Bob F]

Use a very sharp thin long knife blade with a smooth low angle slicing motion. You have to slice it smoothly in several passes. Flexing the foam to open the cut slightly on later passes will help ease the knife passage.

[Roanin]

I was told that an electric carving knife would work well on the blue foam board. I bought one at a good will and it does cut it cleanly but it is pretty slow. Will probably just use it for trimming and build a hot knife.

LJ

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[Jim Yanik]

willshak wrote in news:i8GdnZRGrqIqAa3RnZ2dnUVZ [e-mail]:

you seem to have not READ the guy's post; he was asking HOW TO CUT the foamboard.

construction adhesive will suffice to attach it,...once it's cut to size.

Aside from that,how well did your insulation job work?

BTW,ISTR that there are KITS available for insulating your garage doors.

[Jim Yanik]

"Roanin" wrote in news:i0r1ev$1foe$ [e-mail]:

maybe he could RENT a hot wire cutting tool?

[willshak]

Jim Yanik wrote the following:

As the OP had done, I had read the whole thread on suggestions to cut the styrofoam board up until I posted my response. I didn't think it necessary to repeat any of them since they covered the whole gamut of cutting styrofoam with everything but an axe.

The styrofoam inserts are not as cold to the touch as the wood framing of the door, so I suppose they are working as well as can be expected..

I had the styrofoam left over from another job, so it was available and free.

[Worn Out Retread]

You say that this is for your shop. Is this a commercial shop that will likely have fire inspections? Foam insulation is a fire hazard if not covered by a nonflammable covering like dry wall.

You may be better off in the long term to just replace the door with one that has insulated panels. They are more expensive by far than putting up foam insulation but the result is much better.

If foam is the way you want to go, why not have the back of the door sprayed with foam insulation?

[Ed Pawlowski]

"Worn Out Retread" wrote

Code required it to be covered, but personally, I don't think it is a fire hazard at all. The stuff is made with bromides and if you take a flame away from it, the foam goes out and will not support a fire.

[Hustlin' Hank]

Craft stores such as Hobby Lobby, Micheals and such sell a tool (looks kinda like a coping saw) with a wire and a couple D batteries that heats up the wire and cuts styrofoam cleanly with out a mess. They are less than $10. If you cant afford that, then forget about it.

Hank

[Niner]

You can buy a knife blade that fits in a jigsaw (the smaller size of reciprocating saw, that is). I've found that it goes through solid foam like butter - it probably moves fast enough to create heat without melting very much. Unlike cutting with a razor, I don't get the little tear-offs either. The only way I've seen the blade at big box stores is as part of a "variety pack" of blades.

Henry

[Bob F]

I tried one once, and quickly went back to the sharp thin bladed knife.

[Bob F]

And when it burns, it gives off what poisenous gasses?

[Ed Pawlowski]

Nothing more than any other fire. Carbon, soot, water. While you don't want to breath soot, it is no more poisonous than anything else that would be burning in the house. Take the flame away and the foam goes out.

Factory Mutual did some testing a few years back. The put a small home or office sized trash can in the corner of a room such as you may find in your house. The set it on fire with various wall coverings. One of the methods was just foam on the wall, no covering at all. The trash can burned, the wall burned up a few feet where it was supported by the trash can papers, then it went out. The fake paneling on the wall, however, ignited and spread to the entire room in short time. Same with some drapes.

[Steve Barker]

i worked at a hot tub factory for a while and was using 1" foam to insulate the cabinets. I just cut it on the table saw.

[Malcolm Hoar]

I would worry about the fire risks. I don't think it would pass muster with a code inspector unless covered by a fire rated material like drywall (not very practical on a garage door).

How about considering some fiberglass insulation with a foil/mylar type coating to prevent it shedding and collecting dust? It shouldn't be hard to find some suitable material at your local big box. Much safer, and probably more effective too.

[Ed Pawlowski]

"Malcolm Hoar" wrote

Why worry? Have you ever checked the flammability and flame spread rating? It is a garage door, not a living space.

[Malcolm Hoar]

I assumed (quite possibly wrongly) this was an attached/ integral garage. In that case, I think it's reasonable to treat the garage *like* living space from a fire perspective. And I'm quite sure unprotected styrofoam would not be code compliant in a living area. Also, a significant number of home fires do start in attached garages.

However, if this garage is a separate structure, then there probably isn't much of a fire safety issue. On the other hand, I'm not sure insulating the door is going to help much if the walls/roof are uninsulated.