----- Original Message -----
From: "Fred Fillinger" <fillinger@ameritech.net>
Subject: Re: Europa-List: Post-curing time?
<fillinger@ameritech.net>
>
> > Cheers,
> > I have read the thread regarding the utility of post-curing.
A composite guru in our chapter took a sample of my Aeropoxy lot and sent it
to Stuttgart where they test these things, without post-curing (ie, room
temp). It came back with a Tg of 78.3deg C.> > Ferg> > A064
>
> Not sure which way to take that, but an optimist might say success within
10% of spec by us amateurs, and well sufficient for the purpose, is a good
thing?
Fred,
How many ways can you take a Tg of 78.3degC? I don't get the 10%
thing, but if it's a range of 20% ("within 10%) the lowest TG would be over
70degC. and the highest over 85.
>
> How much time elapsed between lay-up and test, and at what storage temp?
There was no layup. It was a batch of epoxy.
> Supposed to make a difference. Otherwise a pessimist would wonder if them
spec sheets are premised upon fresh product, minimum humidity, and mix
accuracy by weight not to exceed the guano of a flea.
Beats me, lieutenant. I didn't look at the spec sheets. Our
expert just mailed(?) the sample to the test centre and got the answer back.
I don't suspect either he nor the centre (if they mixed it) would have check
for flea droppings. Since it is the DIN test centre for the topic, I trust
both to be more accurate than I, and my greatest ratio mix error has not
exceeded 0.5% yet.
>
> Since Aeropoxy apparently performs better at only room temp than others,
even at your tested 78C, their silence on postcure is curious. The stuff is
marketed for airplane homebuilding, and a second-year law student would be
able to lecture these people about relevant disclosure.
The point is.....?
> Maybe it's because postcure temp of more than marginal benefit for this
product is a bit hot, introducing the risk of botching the job in ways not
conducive to inspection.
I am no expert and have to take some statements at face value so
have done so in this case, as am aware the Deutsch school of Accuracy beats
my alma mater. A hot marginal benefit is over my head. I guess the makers
have a "Can't-touch-me" clause for guys who build outside the stated limits.
As for inspection...................
Best regards,
ferg
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