[TheForge] OT - vinegar vs. epoxy

[Jason Nass]

Filed away with all the other semi-useless scraps of knowledge that I may
very well have use for some day...

Seriously though, I can see occasional application of that quirk of epoxy,
as I do a fair bit of molding and casting in various epoxy resins.

Jason Nass - me at wargoth.com

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce Freeman
Sent: Sunday, August 22, 2010 9:37 PM
To: Blacksmithing List Sponsored by ABANA
Subject: [TheForge] OT - vinegar vs. epoxy

Way OT.

The following quotation is from an article on using seat belt strapping as
the hinge for a small boat rudder.

The interesting part is on the chemistry of epoxy -- i.e., that you can
prevent epoxy from setting using vinegar.  I haven't tried this myself and
am not sure where it would prove useful.  I suspect any acid would work
here, since acids protonate amines and change their chemistry, but I'm not
sure that that's the chemistry involved.


"...you must not allow the epoxy to harden on the strap where it has to
flex. But the ends of the strap have to be well saturated to hold the slide
and the rudderstock halves together. The most successful way I've used to
avoid glue where I don't want it is to get the parts all glued up and
assembled with clamps, keeping the glue off the flex line as much as
possible. Then use a syringe or squirt bottle to saturate the flex line with
vinegar, working it through the fibers, before the glue starts to set. The
acetic acid neutralizes the amines in the epoxy hardener, so it won't
polymerize. The clamped parts won't allow the vinegar to reach the glue on
the strapping between them, so it goes off where you want it to." "

--
Bruce
NJ
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