I had a long conversation a little while ago with one of the technical staff
at SP Systems (who make Ampreg) about post curing, and I have no reason to
believe the basic principles of postcuring laminates are any different for
Aeropoxy. Perhaps if I relate some it will help with understanding?
Rule 1: if you heat an initially cured laminate to x degrees and then let it
cool, in future it will remain hard until heated to approximately x+5
degrees, at which point it will go soft.
Rule 2: a laminate heated to x degrees takes a finite time at that
temperature to acquire the property in Rule 1
The idea of post curing is to raise the temperature of a laminate to a given
point y degrees, hold it there for a bit, then cool it down again. After
this process you can be sure that it will not go soft unless the temperature
now reaches y+5 degrees. Of course, y is selected to be higher than any
temperature the laminate will reach in service.
Rule 2 says that you need to raise the temperature slowly. If you raise it
too fast you will get ahead of the postcuring process, the laminate will go
soft, and it may distort. Supporting the laminate with aluminium angle etc.
helps maintain shape of flanges and trailing edges, too.
Rule 3, of course, is always check these things with the factory. I've done
a slow-build tailkit so I have to postcure. If I had a quick build tailkit,
I'd check with Neville, particularly if I lived in CA, NM, AZ, TX, LA or FL!
I hope this helps.
Regards,
Jeremy
Jeremy Davey
Europa XS Monowheel 537M G-EZZA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
TELEDYNMCS@aol.com
In a message dated 4/16/2003 11:57:46 AM Eastern Daylight Time,
rparigor@suffolk.lib.ny.us writes:
> What components are not necessary to post cure?
>
Ron,
Because of concern about this issue by an A&P friend with lots of composite
experience helping me with my kit I specifically asked this question of John
Hurst and he told me that no components require post cure if you have the
pre-skinned version. Further, he said that all components that do require
post curing have already been done in the pre-skinned kits. Don't know if
you're skinning your own TP, ailerons and flaps, though. Might want to check
with the factory.....
Regards,
John Lawton
Dunlap, TN
A-245 - 425 hours building and still going strong~
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