Sky65

I may have missed it by what is the reasoning behind putting foam inside the frame? If it is galvanized it should not rust? However if you water does get trapped inside, like behind foam, I'm guessing that is not a good thing.

Tom

Amorget

The structural foam will add a bunch of stiffness to the frame.

brando1118

Hi Sky65,
As Amorget stated, the foam will add a lot of rigidity to the frame. My goal is to prevent the frame from flexing between the front and rear boxes. I plan to put a 4 point cage in the rear to tie the rear box together. I will add a spreader bar up front to tie the front box together. But without a full cage (6 pnt or better) I don't have any way to tie the front and rear boxes together. I don't want to run a full roll cage on the street. I plan to drive my car a lot and it's just not practical. So I thought that if I ran structural foam and linked the front and rear box together, it might reduce the full frame flexing that is incurred during hard cornering. Further more, I'm hoping to reduce road noise and rattles by tightening up the frame. The stiffer the frame, the softer you can run your suspension and still maintain great handling. A softer suspension will reduce road and cabin noise. At least this is my theory. We'll see if it works in practice.

As far as moisture getting into the frame between the frame and the foam....yes it's possible. But with the expanding foam and a clean surface, I'm hoping to get a very thorough bond between the foam and the inside of the frame. The galvanizing is the ace to make sure that if moisture exists, there will be no rusting on the inside of the frame. The water would have to be there for years before the zinc on the surface would break down.

cardo0

Wow! That really looks cool and thx for sharing. I'm glad u had all the welding done prior to galvanizing as u would need to grind off the galvanizing areas before welding there. Myself, with all the Power Manual frame mods completed, i would let the foam idea go as if it self expands it could distort the frame now from the inside or bust a weld (seam) open - then what would the fix be? The auto mfrs have all kinds of equipment and testing to control and refine their foam process. I think what u have done here is exceptional by itself and needs nothing else. My 2 cents is put it together and have some fun driving it.

I didnt know there are shops with large enough acid tanks and dip tanks for this. Environmental laws have closed alot of them down. If i even get my car torn down to that step it would be very hard to resist dipping like yours.

And that swiss owned sliver vette crash is a good reminder how fast and vunerable these cars can be. Such a sad ending to a near lifetime of effort rebuilding that car. Myself i have seen the results of a vette crash off road into the woods and burn to the ground - the speedometer was still pegged high. Dont want to get in that situation myself - too many corvette car shows to go to in one life.

Amorget

The expanding foam doesn't expand with much force. Reading threads on other sites about it, people use duct tape to keep it in. If it can't bust through duct tape, it's not warping your frame.

brando1118

Amorget,
Luckily there are plenty of places on the frame for relief. Plus I'll be doing the foam in stages so it won't get too out of control.

brando1118

Hi Cardo0,

Yep!! Life is too short to die in a crash like that. Sometimes we don't have a choice, but that guy, unfortunately created his misfortune.

I'll be applying the foam in stages so as not to let the situation get out of control. Additionally, the expansion ratio for the higher density foam is not very dramatic. There are plenty of relief holes to relieve pressure. It's simply impossible really to pour enough of the mixed solution at one time for it to get crazy. It's just too viscous. It will be a short tube ride into the frame when pouring.

Richard454

Back in the day a lot of 'big stereo" guys used spray foam in their cars- to either help w/ sound deadening - or seal body cavities. The problem is that in the cold weather the foam would shrink and then start squeaking- just saying-

Richard

brando1118

Hi Richard,
Yeah, this is an unknown and may or may not work as intended. I would think that the large car manufacturers wouldn't install foam in the body cavities or frame that would squeak. I would also think that the higher density, modern, polyurethane closed cell foam will not be subject to chronic squeaking. We will soon see!

vette427-sbc

Hey Brando- Bumping this to see if you made any progress on the frame??

SHARKBIT77

CVO2FIXUP

I wonder how much weight that galvanizing added?

brick1234

It looks cool and Im interested as well

brando1118

Hey there 427,
Unfortunately, nothing has changed since this thread was started. Life got in the way. I'm basically working to sell all the extra parts I've accumulated through purchasing the good frame. The one that is galvanized now. I'd like to sell a few more items to gain some room in my garage to do the foam in the frame the right way. Do not worry. I will post all of my procedures and experiences with this foam journey. It should be an interesting ride. I'm in Napa CA on a vacay for most of the month. So no work on anything this month.

vette427-sbc

Ahh I was hoping you would be the guinea pig for this procedure!
Picking up a body dolly this week so I can start down the same path...

sunnym

What ever happened to this project?

derekderek

when you find something old that interests you, click on the user name of the guy and check his profile. you would have seen he was last on here in 2018.

jackson

FYI
there's a boat trailer manufacturer in South Carolina (West Columbia) with a Long history of making galvanized trailers.
Perhaps WESCO can galvanize old car frames, dunno?
https://www.wescotrailers.org/wesco-trailers.html

sunnym

Thanks for the info, I've found a place that could do this locally as well, I'll keep this handy in case they can't come through!

Mark G

Just curious if you've done any calcs or consulted with an engineer or other information to determine if adding the foam is likely to net 'substantial' structural improvement? Or is this a 'shoot from the hip' sort of thing? It seems it would need to be a lot harder than foam. Like a lightweight (pumice) concrete or something. Guys add that to tooling for additional rigidity and strength.

Going back to that demolished vette, I'm struck how well the 'cage' around the driver stayed in tact given the intensity of the crash. Had the driver had an airbag, might have lived (if he wasn't ejected). Doing an airbag mod would probably be a worthwhile consideration for a guy with deep pockets. I've considered doing one myself (my pockets aren't deep, but I've worked on a number of airbag jobs). Don't think it would be that hard to do. It's too bad SEMA couldn't lobby a govt exemption (free from lawsuits) so manufacturers could produce a 'packaged' aftermarket frontal airbag retrofit system for Classic Cars ....like a Vintage Air retrofit. I get the other engineering oversights (vs modern cars with crush-zones, etc) ...but just a dream.


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