With the technology coming along really well I wonder how spray foam would do to seal the frame up completely. I know the stuff is air tight and keep water out really well and it wouldn't take much to seal everything quick any thoughts.

Are you joking?

No actually I was reading up on the subject with a few other site that indicated it worked well for rust prevention inside the frame rails.

Can you post a link? I’d like to read what they say. In all my experience spray foam absorbs and holds water. During the winter that would be some combo of dirty salty water. So no I don’t think that is a good idea at all tbh. I’ve seen body chop shops use spray foam to fill or hide a hole in a frame then paint to match and sell it as a clean frame car. I’ve also seen them do it to fill behind rust spots/holes before using bondo. The rust always gets worse and the foam does nothing to prevent it.

Closed vs. open cell foam.

That said, I still wouldn't use it in a place where it is regularly exposed to the elements. High-density closed-cell foam has been used in unibody vehicles for strength and vibration control for many years now though...

-Charlie

Can you even find closed cell foam in a spray can? When I hear using spray foam on a car I think of the cheap insulating foam in a can you get at Home Depot. Not an industrial grade insulating foam sprayed out using a gun.

really interested to see how this goes

Closed cell stuff is all two part. And structural stuff is very specialized (like, rock hard, 4x to 8x heavier per volume than you are thinking).

Search google for "structural foam chassis reinforcement" and you'll see that even OEMs use it. But again, only on unibody vehicles that I have seen...

Open cell is sometimes used for noise reduction, but only inside a vehicle.

-Charlie

Yes in the context I was reading about it was being used in sports car frames for stiffing up the frame and rust prevention and also noise reduction. u are correct on the foam type structural foam chassis reinforcement it is a two part mix

I see this kind of took off...

@phattyduck @MN4runnerman @T4R_Fanatic

so... I have also been exposed to the building trades and yes close cell poly can be considered part of the structure because it does have substantial strength. it's also a moisture barrier. my house is done in open cell because of the cost and it works really well.

I have a 1950's house when they pretty much never considered energy efficiently whatsoever. my heat bill in January to keep the house @ 70 deg was about $600-$700. after gutting and spray foaming the house the largest heat bill is now about $250 on cold months.

I also wondered about doing closed cell inside the frame, I will admit. My land rover has open cell all over on the inside.

I don't know I think it might work but... you would probably have to find the correctly formulation. it's not UV resistant but inside the frame that would not matter. don't know if it's gas/oil resilient but I would guess it is because its polyurethane based. it does burn and by code has to be covered by a 15 min burn barrier. aka 1/2 sheet rx.

Think I will just stick with internal rust prevention and then DTM epoxy on the outside.

got 2x coats of rust seal down, nasty stuff. organic vapor filter cartridge is a must with this stuff.

it's gooey, it's runny and it's 100% sucks to do this kind of thing but hopefully this will provide good protection. my fingers are x'ed.

unreal work

I'm beginning to notice a disconnect between these images and the title of this thread.

I have plenty of room here for some sketch... it's coming trust me.