Hi Rob (and other builders working with ruby red hardener):
I phoned the company yesterday and they stated that the reddish
color of the hardener is a normal aging process caused by
oxidation.
They also stated that there is no particular expiration date on both
hardener or resin but one has to watch if a mixed batch gels within
specified time and temperature and breaks and scratches properly
after cure.
They also said they receive a lot of calls regarding the red hardener
color but always stae that there is nothing to worry about and that
the epoxy can be used.
That's the words from the source.
Christoph Both #223
Wolfville, Nova Scotia, Canada
HOUSMAN@worldnet.att.net>
Subject: Re: color of Aeropoxy Hardener
When "new" the hardener and resin do, indeed, mix to an amber color but I
have found that as it ages the hardener (and the mix) is a reddish color,
something like a red wine color but far less intense. I suspect it changes
color when it picks up moisture from the atmosphere but it could be from
chemical changes in the hardener over time (something suggested by the
reddish color of an unopened can of hardener).
I don't recall the actual recommended "life" of the unopened hardener but I
think it is on the order of two years. It would be prudent to check with
PTM&W Industries, Inc. (the manufacturer) before using "old" hardener for
structural components.
On a hot day, using PH 3660, I have had 80 to 100 grams of the mix gel in
less than 30 minutes; the PH 3665 has a "pot life" of 2 hours vs. 1 hr for
the PH 3660 that comes with the kit. Check
http://home.fea.net/~canc1/aeropoxy_main.html for details.
Best regards,
Rob Housman
A070
----- Original Message -----
From: <EuropaChris@netscape.net>
Subject: Re: color of Aeropoxy Hardener
> Yup, that would be correct. Once it's mixed with the resin, it is a nice
amber color.
>
> We really like the Aeropoxy. It has a generally pleasant, sweet aroma
rather than the more pungent aromas of some other epoxies I've used in the
past. It also seems to be pretty tolerant of cool layup temps. Our
basement averages about 60 to 65 deg. F in the winter. After we complete a
layup, I put heatlamps on to raise the local temp of the layup, but the
remaining epoxy in the cup sits on the bench, un-warmed. To date, I've
never had a cup that didn't pass the scratch test after 24 hours. The resin
and hardner is always kept at 90 deg. F in a heated cabinet before mixing.
>
> Now, once we start on the cockpit/fuselage this summer that is in our
garage, we'll see what 80 deg. +++ temps do to the cure time! (ALong with
the Wisconsin mosquitoes).
>
> Chris Beck
> A159
> "Dr. Christoph Both" <christoph.both@acadiau.ca> wrote:
> >
> > dear Europa builders:
> >
> > I just opened my first batch of Aeropoxy glue after having used SP
> > all along. I just wondered about the color of the hardener: it is a
> > dark RED. Is this normal? The epoxy is about 2 years old now,
> > never opened.
> >
> > Christoph Both #223, Wolfville, Nova Scotia, Canada
> >
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