Fiberglass adhesion to aluminum?

I did some testing on this a while back.

West systems epoxy /1 inch wide fiberglass tape on bare aluminum sheet
1 square inch of adhesion area
peel strength tested

No surface preparation --- less than 1 pound of force peeled it right off.
sanding --- not much better - maybe 2 pounds of pull
Sanding and etching --- At least 20# - broke the fiberglass tape, and
it never did come off.

If the surface is prepared properly, with etchant, it will work. Otherwise
forget it.


Ron Webb



wrote in message ...
I've got some slight cracking in my aluminum nosebowl and have stop
drilled them twice.
I'm considering backing the cracks with fiberglass in hopes to keep the
vibration down.
How well does fiberglass adhere to aluminum?
What system is better.
I have easy access to the West system chemicals.

Any hints? Alodine first?

Thanks

Dave

One thing to keep in mind is that long-term it is difficult to keep a bond.
This is largely due to aluminum expanding and contracting with temperature
more than Fiberglass does. If the part is kept temperature stable it will
last longer than, say, a part that is close to the engine or exposed to
daily solar cycles. Mechanically bonding the two with some sort of rivit or
screw might help.

D


"Ron Webb" wrote in message
...
I did some testing on this a while back.

West systems epoxy /1 inch wide fiberglass tape on bare aluminum sheet
1 square inch of adhesion area
peel strength tested

No surface preparation --- less than 1 pound of force peeled it right off.
sanding --- not much better - maybe 2 pounds of
pull
Sanding and etching --- At least 20# - broke the fiberglass tape, and
it never did come off.

If the surface is prepared properly, with etchant, it will work. Otherwise
forget it.


Ron Webb



wrote in message ...
I've got some slight cracking in my aluminum nosebowl and have stop
drilled them twice.
I'm considering backing the cracks with fiberglass in hopes to keep the
vibration down.
How well does fiberglass adhere to aluminum?
What system is better.
I have easy access to the West system chemicals.

Any hints? Alodine first?

Thanks

Dave