shawn0890ss

has anybody used foam to fill the frame to prevent water and rust?
as everybody knows the old toyotas are notorrious for rusting, i have allready boxed the frame and sprayed it with undercoating but now i was wondering if anybody has filled the inside of the frame with foam to prevent rust?

opinions, pro's, con's?

Intrepid

My frame was filled with foam when I got it, it appears to be the window sealing type of expanding foam, which doesn't absorb water. Unfortunately, since the frame is full of it, I have no idea if there is any rust forming inside or if any water is getting in and/or being held in. One thing I know, welding onto the frame with the foam inside doesn't cause a flash fire, hahaha.

shawn0890ss

well all the welding i'm doing on the frame is done except when i get rock sliders. i just used that expanding foam spray can stuff for the gap between the floor and another plate i put in and wanted to know if that would work for the frame.

Intrepid

In theory, yes, however, like I said, unless you cut open the frame to check, you have no real idea of whether it will actually keep the water out.

4x4Lamm

It's a sound idea.

Lamm

firemedic

I would not do it, it is just as likely to trap water as not.

Napoleon047

i would not mess with it either. unless your frame is perfectly clean and free of rust on the inside, the foam will not bond to the metal and let water between it and the metal.

a better solution is to drill drain holes on the bottom of the frame to let water out.

Intrepid

Of course, that can also let salt in.

shawn0890ss

hum... i guess it seems no matter what i do its not much help while i'm living in the rust belt

Avsfreak1234

would zinc plating it work? I know that is how most new chassis come from the factory nowadays... just a thought

stevrock

Don't use it, you'll rot your frame from the inside out.

Ask me how I know :cry:

My parts Surpa and Cressida both had this done to them.
Main reason for why they are used for parts, unibody/frames are shot.

Napoleon047

yes, but if you do proper maintenance, those holes will let you flush out that salt very easily

4x4commuter

what about rustoleum before the foam? Im thinking I could pull off the Inside panels of my truck bed (86' ugly) and prep them/rustoleum/reattach and fill that up with the foam? likewise with other body panels?
any thoughts?

Sporin

I use bar & chain oil as an undercoating (GREAT stuff) and I've often wondered if I could figure out a way to spray it into the frame, all the way, down deep, full coverage, really coat the inside with the stuff.

Any ideas that won't make a GIGANTIC mess?

Intrepid

Sometime, probably nearing the end of the summer (in hopes of having my front end done so I can do all the painting at once) I plan to get a couple wire cups for my grinder and a whole bunch of primer and paint in spray cans. Then go to town on the frame, axles, crossmembers, etc. Really clean them up as best as possible. I don't think there is a way to STOP the rust once it has started, but you can certainly slow it's advance.

maxpower_hd

I knew someone that used diesel fuel on a 1979 Ford they bought brand new. They sprayed the entire undercarriage with it every couple or three years. The body rotted out but they still use the truck as a yard truck up in Maine for plowing and so forth. The frame and fender wells still look real good.

Intrepid

It is funny, you never realize how many people are actually on here from up this way...until a rust thread comes around!

The problem with that is that your whole truck smells like deisel, not to mention that it probably smells as it burns off the exhaust and other hot parts. Plus, where do you do that that it doesn't make a nasty mess?

firemedic

I wouldn't, you will still be trapping water, and for what benefit?

Intrepid

Well, in theory, if you used the window foam type stuff, which is in mine, then it is water resistant, so assuming there was no water in there to begin with, it wouldn't allow any in. IN THEORY.
Also, in regards to the flammability, I had to remove a chunk of it when I put on my new rear bumper, since it was out I made my best effort to light it on fire. It would light for a second, but then it would just fizzle out, it wouldn't continue to burn the material.

firemedic

I don't doubt that the foam itself will be waterproof, the problem is that I don't think you will get a perfect waterproof seal, from the foam, to the metal of the frame. It might look like it seals OK, but just a little bit of water seeps in there and it will take forever to evaporate/dry, thereby actually increasing the chance for rust IMHO.