REFLECTOR: Scratch Test

[Al Gietzen]

The scratch test.  Let it cure in the pot for 24 hours.  Take a nail or

screw and attempt to scratch the surface.  If it scratches, then it cured

properly.  This will show you if it is still rubbery.  A bad mix may never

cure to hard.

 

This, of course depends on which hardener, and what at what temperature.
For EZ-84 at 70 degrees, give it more than 24 hrs.  It's cure time is more
like 72 hours, which is nice when doing overlays since you can still get
chemical bonding the next day. 

 

The biggest problem with the hardener is the styrene evaporating.  When it

gets to a low level, the hardener's characteristics will change.  It will

get thicker.  The epoxy will cure much faster (complete cure in less than

eight hours).  

 

Wow; that's fast.  Are you talking EZ-82?

 

I DO NOT keep the hardener in there as I feel the heat promotes styrene

evaporation.  The warm epoxy flows very well.

 

I definitely agree with this.  Keep the hardener sealed in as small a
container as possible, at room temp (in a kitchen cabinet is a good place,
hide it so your spouse won't notice).  If you use an epoxy pump, it is good
to heat the hardener before adding to the reservoir as it then mixes better
with what is already in there, and dissolves crystals formed in and around
the valves.  I've had very good results with this approach - long shelf
life, and never had to disassemble and clean the pump in 8 years of use.

 

Al

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