All,
Since I'm doing a frame off of my 70 coupe, I'm exploring all possibilities with the chassis when it is apart from the car. One of the more intriguing ideas is foam injection into the entire frame or just the corners to stiffen the chassis. I've found a very interesting thread here:http://forums.corvetteforum.com/c3-t...arge-pics.html

And with help from the thread above I've sourced two closed cell expanding foam products that seem up to the task.
1. Is Handi-Foam that can be purchased at Grainger. It is a 2lb density. This can be found most anywhere:http://sprayfoamsys.com/store/do-it-...it-p10650.html
2. The heavier and much stiffer 8lb density:http://www.uscomposites.com/foam.html

Now I realize that to do this the inside of the frame needs to be clean and rust free. Most likely an acid dip would do the trick and then prime the inside as well as the outside with Por 15. I also plan to weld the frame seams and weld gussets in all places that the Chevy Power Book recommends. Also I will be adding a 4 point roll cage to the chassis. All this before foaming because apparently the cured foam does not react well with heat. Has anybody done this? Is anybody considering this? I'd like to hear all thoughts on the subject.
Thanks for your time.

 

I thought about this too. A friend of mine that used to work in manufacturing for Kodak worked with all kinds of plastics and told me of a structural plastic that was stiffer than steel. He said it could be injected into the frame. I need to ask him about that again.

 

Please do V2. Any information you can get out of him pertaining to surface prep would be of great interest to me.
Thanks!

 

IIRC- was it Delorean? Used foam around the frame-

Problem is- it stores water and caused rust through issues.

I'm thinking the Chevy Power book is about is good as you're going to need for the street.

Richard

 

The only foam you need is Sea Foam! it fixes everything! (Maybe a little JB Weld for the big jobs.)

Scott

 

This is an intriguing idea. It should also provide a good bit of damping for the frame. I noticed a big difference after I put hushmat in the interior. Adding foam to the frame should have a similar effect.

 

You forgot the Duct-Tape

 

I've seen it done on other cars but not a Corvette yet.

 

This is the brand I see used a lot.

 

Yep ddawson,
That that is the 2lb density stuff.

Richard and Scotty,
I'm thinking that if the interior of the frame is covered well in Por 15 and the foam is applied uniformly in the frame then water retention will be minimal and so will the formation of rust.

 

I would still be concerned about rust formation, particularly in the damper areas of the country. It doesn't take but a tiny spot of rust that was missed in the frame processing to start a real problem area. Plus, with all that foam, you wouldn't know it until the frame weakened to the point of body misalignment or breakage. No way to inspect it.

Except for a trailer queen or a race car, I would be very skeptical and hesitant about the use of it.

 

I so want to do this - but... there are gussets on the inside of the frame, especially near the end cap, and at the crossmember there- that you would never get foam near. There WILL be open areas, and as a result, there will be water retained.

 

Been thinking about it too... I was going to have my frame galvanized inside and out for rust protection. I drive my car all the time and it does get wet so I wonder about long term rust issues too... maybe a couple strategic drain holes?

 

This foam idea is all well and good until you get into an accident...and the body/frame guy has to pull your frame back to "square" and needs to HEAT UP the frame with a TORCH to pull out buckles/kinks...IF ANY....because the frame is so stout...it will take a really hard hit.

I know "some people" will do what they feel is an improvement ( which is fine and their choice)...in some cases it is an improvement...but often times there is a downside also....often times more than one downside.

Something to think about:

Many new cars have sub-frame rails WELDED to the cab/floor pans in specific areas and the number of welds and their placement is also important...due to the car was crash tested. YEAH...I KNOW...the crash testing/impact bars on the C3 Corvettes was what is was and not as advanced as today's cars..if any depending on the year model....but hear me out. I have SEEN what happens when a bodyman ( NOT ME) actually GLUES in new frame rails in with crash adhesive...versus WELDING them in as designed. The glue is so STOUT...that the rail can not collapse and break away as the welds would give way as designed....thus absorbing the energy. Instead...the glued in rail caused for many more problems due to floor pans buckling where the driver/passenger were and the occupants actually getting hurt due to the car is like a tank and will not give way as designed.

DUB

 

I would just assume the frame (if not the rest of the car) would be trash if it were to ever get bent. No welding on the frame either...

 

All,
This discussion is awesome. I really appreciate all the input. I'm still on the fence about this mod, but my vision for the mod, if I carry it through, is to put the 8lb density foam in these locations only.

 

Not necessarily...I have repaired numerous frames that were damaged....but if it is filled with foam....I would not waste my time.

In a severe impact...yeah...I AGREE it will more than like be TOAST...unless it is some super rare optioned Corvette worth a lot of $$$...

I feel that the area you marked that is between the front cradle and the rear area is where I would NOT put it due to this is a collapse point that I repair often...but do as you want.

DUB

 

The front cradle does not have too much flex due to the spreader bar giving the frame a 3 dimensional design. Solid motor mounts also help in this area along with some kind of solid bellhousing mount to the frame. I would be filling the side rails from the rear kickup all the way to the motor mount area.

 

Where did you get that image? That would really come in handy to make a body cradle.

 

Hi Ctuinstra,
Yes and also for verifying a true frame. Here you go.....

http://www.digitalcorvettes.com/foru...ad.php?t=87024