REFLECTOR: Hardening Hardener

[Tony Babb]

I recently bought new epoxy and hardener, I had plenty of stuff left over
but wasn't sure it could be used as it was over 3 years old. I contacted the
manufacturer of EZ84 and also AS&S support and got the same answer - it's
good for a couple of years after the date of purchase or one year after you
open it. Anything you do after that and you're on your own. I agree with
previous comments that for non-structural lay-ups etc you have little to
lose by trying it if that's all you're doing - for me I still have the
strakes to do...sigh.
 
I'm still not clear if it's just the hardener that you have to replace or is
it the epoxy too? I've had epoxy crystallize and brought it back to life by
heating it for a few minutes in hot water in one of my wife's saucepans -
she was out at the time.
 
Tony Babb
SEFG  62% done, 78% to go
www.alejandra.net/velocity 

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Andrew Ellzey
Sent: Sunday, July 26, 2009 12:05 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Hardening Hardener


My hardener stays in a hot box also, and I have bought fresh hardener from
Velocity factory twice since I received my kit late 2005. Since All of my
major structural layups are complete I decided to try to thin a small batch
of  hardener with acetone to see if would still get hard on some cooling
duct layups that I was building for my updraft cooling. My first try I added
a little two much and it took at least a day and a half to set up. I finally
used a 500 watt light to add a little heat to make it truly get hard. I have
since done a few more layups using less acetone with better results with no
heat needed. I am not a chemical engineer and don't know if this affected
the strength of the final product, but since I knew that these pieces
weren't structural to my build, I felt that I had nothing to loose but a
little fiberglass bid. Try this at your own risk, even though I had good
results I still wouldn't condone this on any structural layups on your
aircraft without checking with the factory or a chemical engineer.
 
Your results may vary.
 
Andy Ellzey
XLRG Getting close.



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From: "KMis178813 at aol.com" <KMis178813 at aol.com>
To: reflector at tvbf.org
Sent: Saturday, July 25, 2009 7:57:20 PM
Subject: Re: REFLECTOR: Hardening Hardener


Brooke
   I have not worked on my own project for quite a while now but I have been
using the hardener from time to time for other projects. I found that the
stuff in the Hot Box gets gooey and is not very useful. The stuff at room
temp will recover with heat but still remains thick. I recently did some
projects at the factory only to notice how nice it is to work with fresh
stuff. New stuff is much thinner and makes the cloth absorb quicker with
less effort and also lighter. The cost of new hardener compared to
everything else we do is cheap. Order in small quantities as you need it and
it will always be fresh?? I'm not saying the old stuff is not useable, just
the fact that I will not use the old stuff on my plane because of it's
properties. FWIW
       Ken
 
In a message dated 7/25/2009 5:39:04 P.M. Eastern Daylight Time,
bwolf1 at tds.net writes:

I know this has been addressed before on this forum, but I am  having  
a problem with hardening hardener.

All of my hardener is less than 2 years old.  It is from the Velocity  
Factory.  I keep some hardener in a 85 deg box.  I have been away from  
my project for 3-4 months.  Now, I noticed that it is getting a little  
thick, somewhat like a gooey tar.  I  tried heating it by putting the  
gallon jug (with less than a quart of hardener in it) in water at 150  
deg.  I let the hardener get to about 130 deg for about 15 minutes.   
The heating certainly made it more viscous, but as it cooled it got a  
little thick again.....but not as thick as before.  I don't have much  
confidence in the heating trick.  What did I do wrong?

Just for grins, I checked on two jugs of hardener which have been  
sitting in my basement for 2 years.  The temp down there stays a  
pretty constant 70 deg.  Much to my chagrin, both jugs seem to have  
solidified into a crystalline mush.  Any ideas?!!

Brooke




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