I have run into an alarming situation. I find epoxy BID applied to the firewall
material does not have great bonding characteristics. I have not seen this
brought up before. I discovered this, as to attach the instrument panel, I
epoxied
a 4 ply BID flange onto the lower firewall inside face. After cure, I was
shaping the flange and found that it peeled away without much difficulty.
This brings into question the bond of all the many places that fiberglass BID
is used to reinforce the reduxed joints on the firewall. I have attached a
picture
showing the scuff sanding preparation I did to the firewall surface. Hopefully
the photo remains attached. I am using new epoxy and no unusual temperatures
were prevalent. The epoxy cured as expected so the epoxy mixing proportions
shouldn't be in question. It seems that the phenolic firewall material
just does not allow a good epoxy bond? Is this something that is known and
expected
or is this not as it should be?
Thanks,
Bill McClellan
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