yo yo yo,
ive been off all these boards for a few years now, but have kept building my car.
the focus is street/auto x.
Right now, i want to look into ways of stiffening the chassis, roll bar is obvious and will be done later.
ive heard some people talking about using "great stuff" home sealant sh*t to stiffen the body. Ive heard INIFINITY uses some similar method and it works well for them.

ive studied the EG's body structure pretty extensively, (junk yard cutaway views #1!) and most of my interior is removed, i have an idea of where i'd use this stuff (filling in behind where sheet metal is sandwiched and spot welded?), but i want to see what you all know first.

1. does it work well (if properly done)?
2. where exactly would this stuff be injected?
3. what prep work is necessary?

any help is greatly appreciated THANKS!
-steve
"jtcc is the killah"

 

If you are gonna get a cage eventually, the foam is a waste. Since you wont need the foam once the cage is in.

 

You need to check the legallity of that sort of modification as well. It doesn't sound to me like something that the SCCA would allow - especially since that **** is more flammable than gas.

 

I wouldn't specifically use "Great Stuff", there are products made for this application available on the market.

I read a bunch about it on one of the miata lists a few years back, and I think they decdided it wasn't worth the trouble. Maybe ask at miata.net and one of them will remember.

 

seam welding and then a nice weld in cage = stiff

Will

 

There was an article about this in sport crappact car a while back. I think it was on a 300ZX, what they did was take all the panels from the interior out, and tape up the chassis parts that have holes in them with masking tape, and inject the foam (it was first mixed) into the gaps in the body. Gaps in the pillars, gaps in the sandwiches, etc, etc... They said it was messy as ****. Did it work? Who knows, maybe. Is it legal? Probably not. Besides, a good welded cage will render any of this stuff useless. Some cars (like a saturn with a steel spaceframe) would proabably gain some benefit from this goo.....

Materials Science Lesson:

The foam that they used was a structural foam, probably a S-RIM process. S-RIM is structural-reaction injection molding. Basically, its a polyurethane thats mixed with another component that adds stiffness, the two mold together and form a composite of goo and harden. Most of the RIM processes produce foam and are used in interior applications.

Ryan - who is almost done with his thesis on Alternative Materials in Automobiles

 

When PU foams first became viable, a rail car company in Seattle had a big to-do and invited a bunch of big-wig guests to see the first reefer (as in fridge, Spicoli) get its insulating spaces foamed...

It went just fine until this freaking, great train car started coming unzipped at its welded seams from the pressure of the expanding foam. Dooh!

Kirk

 

haha! rock on... i should hope a car's seam welds dont come undone...

 

Filling your fenders with foam would not be SCCA legal in Stock or Street Prepared classes. Probably OK in Mod class.
Sorry.
Steve

 

i doubt i'll go for this mod thn, since a roll cage is in the not too distant future anyway.
steve