Hi,
Graham Clarke wrote:-
>>Anyone at the tail stage should carefully note the instruction to scuff
and groove the bushes within. <<
Graham Singleton wrote:-
>>My advice is to thoroughly dimple the stainless steel bushes with a 3/16
>>drill.
Be careful not to distort the inside surface or the bush will jam. I don't think
scuffing with 60 grit is enough. Epoxy won't chemically bond to stainless,
ordinary or any plain metal.<<
I know of one early builder that had the inboard bushes come adrift. I didn't
enquire
at the time if the outboard ones had
also given trouble.
It's problems like this that can only subtract from the longevity of the
finished
aeroplane. I would like to think that the
Europa could be tomorrow's work horse to take over from the Jodel -why not? I
don't
like the idea of relying on an epoxied
bush keeping me in the air, I'm used to metal aeroplanes where you can nail
things
together!
I agree with Graham, metal can only be mechanically bonded with epoxy and relies
on getting a good key on the surface.
Stainless is the worse of all to get a good key on. Groove it, scuff it, dimple
it, but make sure that it is clean and free
---From grease, MEK or Trike is best(if you can get it!), but remember that MEK
doesn't
like the blue squashy stuff - it eats
it for breakfast.
A better solution, with the necessary approvals of course, would be a mechanical
one Weld two butterfly wings, one on
either side of the bushes, and sandwich these in flox between the BID and the
plywood
pieces. That way both the lateral and
rotational movement would be inhibited should the bushes become debonded, which
is very likely.
Is there is different type of sticky stuff that could be used that is more
suitable
for bonding metal?
Dave & Margaret Watson
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