Spray in foam insulation
 

Why have I never seen anyone spray expandable foam in to the cavities in the roof , back of cab, and in the door jambs ??? At first glance it would seem to quiet the cab of the truck down and insulate it from the heat and cold in the winter ??? Am I missing something here ? About the only thing I can think of would be condensation ? Is that the reason they do not do it ? Kieth :gmc2:

Re: Spray in foam insulation
 

two words....rust magnet

Re: Spray in foam insulation
 

I put it in my roof.;) It's closed cell. You put it in houses. I don't see how it would gather water.http://www.sprayfoam.com/npps/story.cfm?nppage=256 Hope I never have to weld on my roof.:lol:

Re: Spray in foam insulation
 

Not if you use the correct stuff in the correct areas.

As long as you use closed cell foam and as long as you make sure the surfaces you apply it to have been painted there should be no rust issues.

If you spray it on a bare steel surface, and moisture does get in between it and the metal, of course it will then be a "rust magnet".

Like everything else, do the research, do the prep. work and you will get good results.

Re: Spray in foam insulation
 

true enough. The stuff my buddy used on his car ended in disastrous results though. Some of his panels ended up distorting when the stuff expanded and hardened. Best guess is he put to much in there.

Re: Spray in foam insulation
 

Excellent Point! :agree:

Re: Spray in foam insulation
 

Before making a decision I’d suggest reading the Wiki article on spray foam, and then do some research to find out which type you will or should be buying. Some are water “resistant”, others don’t mention one way or the other, and there’s also the risk of over expansion damaging the panels. The other problem might be, like inside a door for example – the foam may truly never absorb water, but it may trap it in areas that might have otherwise drained or had a chance to evaporate. Also consider how much work it’s going to be removing the foam if this becomes necessary for a repair, or to run a wire, etc.

http://en.wikipedia.org/wiki/Buildin...tion_materials

Re: Spray in foam insulation
 

It's hard to believe water would get in between the foam and the metal. The stuff expands and makes a pretty good seal. Kinda messy though. You don't want to get it on anything. Like your seats.:waah: When I did my cab it came out everywhere. Even a week later it was leaking out around the windshield rubber. I think it helps keep the water out. Keeps the air out. Air has moisture. I did more because I was doing body work on the roof and it kept bending in when I sanded on it. Don't bend any more.:lol: I don't think I would use it in the doors. I also put it in the area above the gas tank.

Re: Spray in foam insulation
 

Re: Spray in foam insulation
 

The reason it is a rust magnet is that condensation builds on metal in cold and heat not to mention the car wash and rain. The moisture builds then traps in the cavities of the spray foam, it does not leave because it is trapped within a cavity that does not easily get air. I would be willing to bet money that if you use the stuff, and le your truck get into weather or even a car wash, eventually (sooner than not) your spray foam will be your biggest demise. I have seen a bunch of people use it on vehicles and none of them happy with their wasted efforts. The only real way I could see using it would be to rubberize the surfaces you would be coating. Then it would not affect the metal because it would not come into direct contact. Just my famous opinion.

Re: Spray in foam insulation
 

If the foam is sprayed on the metal I don't understand where the moisture is coming from? It can't come through the metal? Can it? There's no air movement through the foam. They spray it on metal buildings all the time to insulate them. I don't realy know.:waah:

Copied from the above link.

Poorly insulated and sealed metal buildings experience significant sweating, especially if they are climate-controlled using HVAC systems. The moisture condensation can cause water damage to the building interior and premature metal corrosion. Corrosion to a metal roof decking system can be a major safety hazard for anyone with roof access for service or repairs.

Condensation can easily form inside a poorly insulated metal building with interior humidity as low as 20 percent. With ccSPF sprayed to the existing roof deck, a continuous layer covers fasteners, metal panels, and roof penetrations (e.g. pipes and supports), and completely separate metal beams, joists, purlins, and the metal roof deck panels from contact with the outside temperature and humidity. This thermal break eliminates the potential for condensation.

I'm not to worried I live in a desert. My truck will be inside a heated garage when its wet out. I'll let you know in ten years. I might be looking for a new old rusty looking cab. Maybe, maybe not.

Re: Spray in foam insulation
 

are we talking about pro spray on expanding foam here or are we talking about the stuff they sell at home depot/lowes/ect? There's a big difference between the two, namely in the application and coverage

Re: Spray in foam insulation
 

Somebody put some in the two back bottom corners of the cab of my 66 I have now.
Never really gave it much thought, and haven't noticed any obvious issues - yet.

Re: Spray in foam insulation
 

Hey thanks for all the input, I have some experience with spray on insulation in Reefer trailers. As these trailers age they do become impregnated with water (this also adds weight) I am going to call the professionals who install this stuff and see what their experienced opinion is, will then let the board know. Thanks Kieth :gmc2:


I think the heat and cool cycle along with high humidity make certain types of this material a bad deal, but there may be other types of foam available that will work well (when they installed a new sliding door at my house they used a type of foam that did not expand and it really locked the door into the frame without a lot of additional support maybe something like this would work. will let you know what the pros say.........

Re: Spray in foam insulation
 

I got a pair of doors that I thought were good, but when I started poking at the corners I went through, when I cut the corner for the patch I discovered the foam someone had sprayed in there; all the metal that the foam was touching was too far gone to save,I ended up throwing the door away...
oh, and the foam still had water in it, you could squeeze it and it would come out..

Re: Spray in foam insulation
 

keeps us informed, I want to used foam on my truck too. I am not using it as water sealant but noisy and temp. reduction.

Re: Spray in foam insulation
 

:eek:
Maybe I had better take a closer look at the foam someone sprayed it the back corners of my cab.
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Re: Spray in foam insulation
 

3M and other professional body repair companies make spray on (even in rattle cans) products for coating/deadening the inside of doors/panels. Talk to your local paint n body supply house.

You might also look at LizzardSkin- they make an acoustic version and a thermal version (IIRC it goes on primed metal- not bare)
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Re: Spray in foam insulation
 

All foam is not created equal. The last place I worked we were involved in using SOFI (spray on foam insulation) on a hydrogen fuel tank for an unmanned aircraft. This tank had SOFI on it's exterior. NASA uses SOFI on the exterior of the space shuttle main fuel tank. We consulted with them because they are the world leading experts on SOFI. There is a huge variety of what can be used and the costs can be anywhere from reasonable to ridiculous.

Here is a more "down to earth" article that talks about open cell vs. closed cell SOFI and what their advantages / disadvantages are. http://www.sprayfoam.com/spps/ahpg.cfm?spgid=6

As I stated previously: "Like everything else, do the research, do the prep. work and you will get good results."

Here is a product specifically recommended for boats and automotive applications: http://www.wholesalemarine.com/p/F-E-654/

Re: Spray in foam insulation
 

There is auto body spray foam (3M?) made to replace OE foam for body shops, but IIRC it was $$$$, and required a special gun.

Re: Spray in foam insulation
 

Thanks for all the input, I will do a lot more research before continuing with this line of improvements. Kieth

Re: Spray in foam insulation
 

X's 2 for Lizzard Skin. Spray on application, durable, non porus, professional looking finish. Leave the spray foams for your house or boats.

We have removed multiple panels that have been rusted out form the inside due to spray foam.

Re: Spray in foam insulation
 

The lazy PO put expanding foam in the cab corners of my 66 instead of replacing them. cab rusted even worse and now Im sourcing for a new cab :(

Re: Spray in foam insulation
 

Get that stuff out of there! :m6:

The holes were made by me, scraping thru the paint to see just how much rusting had occurred. Crap!

So what if the foam is water proof - big deal! if you don't clean and seal the metal good, the foam is just going to hold the moisture there. :mad:

.
http://i54.tinypic.com/ib9nxy.jpg

Re: Spray in foam insulation
 

Oh, btw...

The foam I tore out was nice and dry.
The metal under the foam was wet. :(