Re: Recommended Epoxy System?

Larry Severson

If you go to vacuum infusion using the PTM&W (2712) epoxy, the Tg can be raised to 212 degrees F. But that requires slow post curing cycles. That means raising the temp 10-20 degrees in at least 2 hour cycle periods. Every time you take the plane out of the hanger, if the temp is above the initial curing temp, the Tg will be raised, as long as the new temp is higher than the previous time. Unfortunately, if the plane is exposed to above Tg temp at any time, the plane is subjected to epoxy delinking and plane sag.


Each epoxy has a different ultimate Tg.


Larry Severson

18242 Peters Ct

Fountain Valley, CA  92708

(714) 968-9852


From: Q-LIST@... [mailto:Q-LIST@...]
Sent: Friday, August 28, 2015 10:44 AM
To: Q-LIST@...
Subject: Re: [Q-LIST] Re: Recommended Epoxy System?



I'm not Charlie, but I've done quite a few
postcuring tests and DMA/DMTA Tg tests on epoxy
systems in various projects. I always saw a
definite upper limit for an epoxy system, no
matter what postcure cycle. Quite often they were
amazingly low, like 80 degrees Centrigrade for
low-viscosity vacuum-injection systems.


At 19:11 28 08 2015, you wrote:
>Thanks Charlie,
>Can you tell me, does Tg rise each time the
>epoxy gets heated to a higher temp than the prior heating?

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