The Stovebolt Site Forums The Shop Area Paint and Body Shop Spray in insulation

What is thought of the idea of using that spray in insulation you can buy at the hardware store to insulate the top of the cab? Seems like a good idea to me. Spray it in and it expands to fill the empty space. Shouldn't deform the metal as it doesn't break out sheet rock walls. It would be a good idea to run wires first but I bet one could run wires using a coat hanger if they needed to. Any comments? Dave.

will it bulge the headliner down?
does the foam have a constant expand rate? 20 - 50 - 200 % ?
will it fill where you want it too, even though you can't see where it went because the headliner is installed.?????

My only concernes on the spray foam would be condensation between the foam and the steel of your roof causing condensation and inevitable rust?
Just a thought.
Tim

carolines truck, the headliner is sheet metal, I don't know about the rate being constant or not. I think it expands to fill a void and stops at resistance. Where ever it goes it can be cut away if visable.

SW Radial, The idea is the same as your house. Surely the stuff doesn't rot the walls of our houses from trapped water?

Thanks for the replies.

Dave,
My thinking is that our houses are made of wood and steel is a different animal when it comes to condensation.
I just think back to when i first built my shop and had just the steel sided walls the first winter and when the sun would come up how much WATER would run down the walls inside.
and to look inside my toolbox to see all my hand tools covered in condensation.
Now my Dads shop is all wood with no insulation and never had this problem.
I may be way off base here ...was just tossin out an opinion.
Tim

WAIT...... DON'T use the expanding foam insulation used for home construction. It WILL absorb moisture and WILL rot your sheet metal. Go to an automotive supply store and you can get expandable spray foam used to fill unibody sides for sound deadening. There are many kinds of automotive foam, make sure you get the right kind for what you want. oh yeh, it is kind of pricey too, more than the Home Depot kind.

Rust is a real problem. I don't know about the new foams available, but Volkswagen beetles used some kind of foam insulation in the late 60's to fill a cavity between engine and interior. It worked great to stop noise and fumes, but many of them rusted out in a few years. Look for rust just behind the rear side window on those old bugs if you see one that has not been restored.

Mar-Ktech

I don't think I would use construction foams on a car/truck.

Window manufacturers no longer recommend using that stuff for installing windows in homes because the expansion would actually warp the window frames and make them hard to open and close. It was used between studs and the frames and would normally be covered by trim later. If it can bend a window frame it can certainly cause a problems for a headliner.

Transplant is right. My company sells residential windows and have come across this problem in most instances. It works great to fill voids, but expands way beyond what could be useful for what you want. I also agree that it would act like a sponge and being in constant contact with your roof would go against all that you are trying to do. I recommend finding a product designed more for what you are hoping to accomplish. Hope this helps

There is a product called "Great Stuff" It works very well for this application. You can obtain it at Home Depot. This foam does not absorb water, It will fill a void and stop unless it finds a hole and it will protrude through the hole. This product is semi rigid, or hardens to a firm but not hard state. Buy a can and try it, I think you will like it.

Frank

The only way I would attempt to use that foam would be if I had my cab on a rotisserie and could foam it from an upside down position. I would be concerned about rust under it and do some research on the subject. There are a lot of insulation that would work for you, and as well as the foam stuff. I am using Second Skin.
http://www.secondskinaudio.com/

Wow, I appreciate all the replies and have learned a few things too. I probably won't put anything up there. Maybe a more powerful A/C.

SW_radial, My garage (the one attached to the house) gets sopping wet just like you describe for your metal shop. My metal shop (6" fiberglass insulation inside the metal walls & metal studs) never has condensation. ? go figure.

Again, thanks guys. Dave.