https://www.jaguarforums.com/forum/w...me-car-144001/

 

Have never heard of using foam for stiffening.

For sound dampening yes, but the polyurethane foams, open or closed cell, don't have enough rigidity that I can imagine they would do much.

Think of a memory foam mattress or pillow... how is that stuff going to make a chassis more rigid.

 

Well ... So now, thanks to me, you are aware of this!

Henkel - Virtual Car 2011 - Applications

1991 Nissan Sentra SE-R - Transformation Of A Classic - Turbo & High-Tech Performance

 

Polyurethene foam is used a lot in boatbuilding both for stiffening, and as a "former" for GRP. I have a GRP rudder full of the stuff. I think it's inside most surfboards. It's the same stuff you can get in aerosols for sealing and insulation in building construction. Once set, it can be moulded, cut and shaped. If I lived in a climate where it never EVER rained, I might consider injecting it into hollow chassis members and other cavities in a steel car for sound insulation and maybe a bit of extra rigidity but I would not contemplate doing that where moisture could be present. Capilliary action would suck the moisture into any gaps between the foam and the steel, and a few weeks later, you would have rust from the inside out.

 

This is absolutely true. Early Learjets had sprayed-in polyurethane foam insulation. Even with excellent metal prep and primer it led to very expensive corrosion repairs and time consuming foam removal. I would put foam only in a non-metallic structure.

Mike

 

as regards the injection of the foam, I think you use a high density foam (which does not absorb liquids) and before injecting into the cavities of the frame, the wax is sprayed in (that normally use refinishers to protect the joints) that does not allow to possible infiltration of turning into rust.

 

There's a TSB somewhere about resolving noise from the a-pillar area on the XK100. The solution? Fill the a-pillar cavity with expanding foam from an aerosol.

I don't recall hearing anything about a-pillar corrosion so maybe it's not quite as bad an idea as it sounds, or maybe moisture doesn't get trapped in that area anyway.

 

As Jaguar discovered with the early XJ6 Series 1 front suspension cross member. Filled with foam to reduce transmitted noise, these regularly rotted out in the wet UK.

Graham

 

read what "TDI PLC" wrote about chassis of our XK8/R

Jaguar XKR Chassis and Suspension Upgrade

Perhaps the problems of the frame with this treatment ... could be solved?

more experience on this topic on Nissan Z32

Z32 Chassis Stiffening 101 - TexasNissans.com

 

Have used expanding foam a lot in various cars in A/B/D?E pillars to stop noise transmission to roof. Blocks of foam that expand fully as a car passes throgh the paint oven are used on a lot of new vehicles to reduce noise, add stiffness and improve crash performance. I do agree that the stuff should not be used in sills and chassis sections that get wet and need to drain.

 

to know EXACTLY where spray foam in boxed structural of car would need chassis diagram of our cars. Anyone can help me in this?