PPG Concept curing question

[Gray E Fowler]

Bob

Dry and cure are different terms. Paints "dry" which means that the paint 
resin is a solid at RT and it is cut in a solvent. When the solvent 
evaporates, a dry film of resin, pigment and filler is left behind.  The 
Concept resin is exactly the same...BUT the finished product adds a 
isocyanate curing agent which actually crosslinks the resin polymer. PPG 
Concept drys first to the touch then continues to crosslink react or 
"cure". The stuff that is dry in the can just had the solvent evaporate.

Try this experiment.....mix the Concept per the instructions, spray your 
enitre plane. After it is "dry" (1/2 hour) wipe your plane with acetone-it 
will wipe off. Spray your entire plane a second time but let the Concept 
dry AND cure then wipe it with acetone.....and it will remain. You can do 
this with a test coupon instead of using your plane, but the results are 
not as rewarding.



Gray Fowler
Principal Chemical Engineer
Composites Engineering



Bob Kane <getterflash at yahoo.com> 
Sent by: discussion-request at nsrca.org
10/20/2005 02:51 PM

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PPG Concept curing question






I am using PPG Concept (DCC) paints for the first
time. I had innocently assumed since this was a
two-part paint, it cured much like epoxy. But after
working the stuff for a couple of weeks I noticed the
unmixed paint in the empty cans was "dry".  So, my
assumption is the paint will "dry" on it's own, but
would not have the durability of properly mixed paint?
The hardener gets all the molcules link arms and form
a tougher material? Thanks in advance.

Bob Kane
getterflash at yahoo.com


 
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