Foam?

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PostPosted: Tue Nov 05, 2019 10:28 am
Why do they put Foam in A pillar or Pillar posts?

I recently repaired the Firebirds A pillars (Wind sheild side posts)
During the repairs a large chunk of hard foam was removed from inside the A Pillars before I welded it back together repairing Rust.
It appears the foam was injected through a small hole on back side of pillar, Just wondering why the factory did this what its purpose was????
My only conclusion is its to keep wind and rain out.

The foam was a small blob inside the post just at the base and not all the way up through the whole post. I have seen the same thing on other cars I have parted out.
Just wanting to know the purpose and why its there and if I should replace it or not?

Also I am needing suggestions on a Good Paintable Seam sealer that wont dry out and crack prefer an affordable one one I can mix and apply by hand with a brush.

I been thinking about using an aircraft fuel tank sealer on a lot of the stuff on the bottom of the car either 1422 B1 or B2 or Proseal both are fantastic sealers.
Proseal is cheaper of the two and both are great at sticking to most anything that is Oil free They both stay flexible and do not crack for many decades but paint doesn't like to stay stuck to it forever if it flexes a lot and sees wind speeds over 500 mph lol I know this first hand.
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Tue Nov 05, 2019 11:11 am
I can get a quart of the Pro seal 890 with a working time of 2 hr cure time of 24-36 hrs for $200 from aircraft spruce supply.
I think a quart should be enough to do the whole car ??????? Thoughts?
I am doing inside trunk and bottom of trunk firewall/Cowl panel and rear wheel wells and the Trunk drop offs.

https://www.aircraftspruce.com/catalog/ ... /ps890.php

The stuff is mixed by weight and faster set up stuff can be purchased, say you only wanted a 15 work time just order 890 B1/4 15 min or B1/2 half hour, B1 one hour, B2 two hours.

I am not to concerned with how well Paint adheres to this stuff because of where I am putting it, and I think the Paint adhesion issues I have seen with this stuff over the years has to do with the flexing of the aircraft and the wind speeds of jet aircraft both of wich you don't see with a typical street car.

But still if some one has a better one or cheaper????
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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PostPosted: Tue Nov 05, 2019 11:31 am
I have been using the Lord Fusor seam sealer.
https://www.lord.com/products-and-solut ... ion-sealer

Fits a regular caulk gun, adheres great, is fairly easy to work with.
I like to epoxy primer first and then apply.

As for the foam, maybe some Great Stuff?
1968 Coronet R/T


ACTS 16:31

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PostPosted: Tue Nov 05, 2019 1:08 pm
Dennis, this is something I read on the foam thing awhile back... it's a short read.....
https://www.bodyshopbusiness.com/auto-f ... nderstood/
When I was a kid I had always heard the old car body guys talking about it and they thought it was mostly to stop the pillars from being a sound "resonator." And of course, the I could see the weather seal thing as well.....
Metal, wood, fiberglass, we work it all... www.furniturephysicians.com We can restore the irreplaceable!



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PostPosted: Tue Nov 05, 2019 4:14 pm
Thanks Guys!
Darrel that was a very informative now I just have to figure out which type to use to replace what I removed. Think I am gonna have to give in and buy the assembly manual for that car.
That should have the original GM part number that I should be able to cross reference I think???? or maybe contact a GM parts counter and find out???
Dennis Barnett
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

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