Mailing List lml@lancaironline.net Message #8054
From: Marvin Kaye <marvkaye@olsusa.com>
Subject: Re: Dark Hardener
Date: Wed, 03 Jan 2001 20:50:58 -0500
To: <smcgowan@bellsouth.net>, <lancair.list@olsusa.com>
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The word from the chief chemical engineer at Jefco is that the
discoloration of the 3102 hardener has no bearing on the strength
characteristics of the resulting matrix.  At least that's what I and other
builders have been told routinely ever since the problem was first
reported.  I went ahead and used quite a bit of it on my airplane but am
feeling less confident about it as time goes by.  I haven't noticed any
deterioration of any sort, I'm just not feeling 100% at ease with the
stuff.  In discussions with another builder for whom I have great respect
the hypothesis was posed that what if there is some long term deleterious
effects caused by the chemical reaction that changes the hardener's color
that haven't been identified yet, as the problem is simply too recent to be
able to address long term issues.  Personally I don't have an answer to
this conundrum, although I think it is something worth considering.

I understand that Michael Engineering (maker of the sticky stuff dispenser)
is under new management and the subject has been broached with them.  They
are apparently looking to redesign the check valve system to incorporate a
material that won't react with the hardener.  As of this point in time I am
not aware of a solution having been found.  In the meantime I'm planning on
dispensing from individual containers using inexpensive disposable pumps
that do not react, and apportioning my materials by weight.  I, personally,
am going to forego the convenience of the dispenser until a solution has
been found.

Please contact Jefco directly and ask for Ed, he's the engineer who
suggested that everything was ok with the discolored hardener.  With his
first hand information you should be able to reach your own decision
regarding what, if anything, there is to do about this situation.  You
might also talk to the management at Michael Engineering to see if they are
any closer to the "fix".

   <Marv>

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Please send your photos and drawings to marvkaye@olsusa.com.
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