> I have a question for the builders list. I bought an "orphaned" Europa
> Clasic
> kit and the former builder didn't get too far with it. I am currently
> building
> the wings and I am using fresh MGS epoxy because I was concerned that
> the Ampreg Epoxy that came with the original kit in the early to mid
> nineties
> was past its usable shelf life.
Many years ago I contacted SP about the useful life of Ampreg. The
technical adviser said that the shelf life they publish was underwritten by
periodic tests on batch samples kept at their factory and they had satisfied
themselves that it remained usable at 2 years. Unfortunately they kept no
samples older than 2 years (as their primary customers for Ampreg 20 were in
the boat building industry and typically used the resin soon after buying
it) so they couldn't comment on older batches. She did say that she
wouldn't be surprised if the material was still entirely usable for our
purposes beyond that time but that they could not vouch for it. She also
said that some properties such as the viscosity, affecting ease of use, and
'setting time' might drift out of spec. beyond 2 years, without
significantly affecting ultimate strength. Always assuming storage within
the spec. parameters, of course.
They would (then) be willing to test a sample older than 2 years supplied by
a customer to see if it was still viable, but the cost made it prohibitive
unless you had a number of packs from the same batch.
Like you I have found that well-out-of-date Ampreg cures perfectly well and
I have used t for a number of round-the-house jobs. I wouldn't use it for
the aircraft, though (and you must not do so in the UK).
John Cliff
#0259
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