expanda foam in the sills/chassi...?

**IN 05 NT** · 15-10-2007, 07:48 AM

bit of a random q's

alot of the older guys in my club FILL there track car SILL's and chassi rails with expanda foam, the stuff you get from bunnings....

my old 3t ke20 had also had it done...

the rumour is that it will stiffen the body,

would it be worth it?

have you tried it?

blake

**ian** · 15-10-2007, 08:03 AM

hi blake
it does make a bit of difference
although if you have any oil like substance like fish oil or rust preventative in the sills the foam does not adhere properly
also it makes it hard to do any welding around the sills eg roll bar mounts etc cos once it starts burning it is a real pain to try and stop
it smoulders for hours
cheers
ian

**jezza323** · 15-10-2007, 08:09 AM

it can also promote rusting if there is moisture trapped, however as it is a race car, and as such will have a limited life anyway....

**ian** · 15-10-2007, 08:16 AM

i dont think that there is a real need for it
cos the roll bars will stiffen up everything anyway
ian

**clubagreenie** · 15-10-2007, 08:34 AM

Used to be done, when alloy cages were legal. Holds moisture as said and won't adhere (which is where stiffening comes from) if other treatments are there first.

Messy, cheaper to buy as a two part mix from fiberglass shops, a lot more fun to play with left over mixes and up the catalyst ratio.

**thepeter** · 15-10-2007, 01:01 PM

Agreed on the fibreglass resin option. You get ALOT more for less money, as less than 2 litres can do the entire rail/sill capacity of an ae86...

The bunnings stuff (Bostik i think) is approx. $20 per can, which goes very fast...

**IN 05 NT** · 15-10-2007, 05:09 PM

haha awsome,.

i know the sill will be dry of moisture (its been siting in the workshop for 9months so far)

not sure if they have aplied fish oil or other shit,....

guess i'll add it to the list of stuff to do

cheers, blake

**MWP** · 15-10-2007, 07:29 PM

The 2 pack epoxy based stuff should be closed-cell too, which wont absorb/hold moisture.
Will help with rust prevention compared to the spray can stuff.

**clubagreenie** · 15-10-2007, 09:32 PM

No it's still the same yellow stuff. You can get Styrofoam as well (closed cell) but won't have the same adhesion properties and compresses more. Though the open cell stuff will also compress, without rebounding.

Also means that any dings you can get out easily (if at all).