REFLECTOR: pasty hardener

[Jack Prock]

After we talked about this a few weeks ago, it has been bugging me that I didn't have
some documentation for using and storing the EZ-84 hardener. My paranoia got the best
of me, and I was bored today so I did some research. The attached site is the manufacturers 
technical data for the EZ-84 hardener. On the second page, it shows storage and handling
instructions. The hardener seems to tolerate a fairly wide temperature range for storage.

http://www.fiberglasswarehouse.com/tds/EZ83_EZ84_EZ87_tech_data.pdf

Jack


  ----- Original Message ----- 
  From: Jack Prock 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Friday, January 25, 2008 9:31 PM
  Subject: Re: REFLECTOR: pasty hardener


  How much useful life do you need? Are we talking 5 years to 3 years? or 5 years to 1year. 
  Is that something you've heard? or is there some documentation that I missed?
  In 2 years, everything is still working well. 

  I also only mix up what I need, so it is usually used in 30 minutes or less, then I
  mix more if I need more. The only time I've had a problem with reaction time being
  short was when it was 110 outside and close to that in the garage. Otherwise, the
  working time seems fine.

  Seems to work great so far... guess it's just a preference.

  Jack
    ----- Original Message ----- 
    From: Al Gietzen 
    To: 'Velocity Aircraft Owners and Builders list' 
    Sent: Friday, January 25, 2008 8:02 PM
    Subject: Re: REFLECTOR: pasty hardener


    Andy wrote:

    I have found that keeping the hardener in the warming cabinet shortens the

    useful life



    That was my experience also.  It darkened more rapidly, I guess due to oxidation of the amines, or whatever.  The other factor is that the reaction rate when mixed goes up exponentially with temperature, so it kicks off much more rapidly at 95 F than at 75F which significantly reduces pot life.  At 95 F, if you don't use what you mixed in about ½ hour it begins to thicken and doesn't wet out as well; whereas at 75F you might have 3 times as long. Yes, at 75 you will get some crystallization after some months if you are not using it; but a short term warmup to 110 or so and stirring gets it back in shape.  Each time I added resin or hardener to the pump, I heated it prior to pouring it in.  Kept things working well - never had to empty and clean the pump.



    I did on occasion put mixed epoxy in the freezer, and could warm it up and use it a day or two later.  Also works for epoxy primers and acrylic paints.



    FWIW,



    Al





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