<br><font size=2 face="sans-serif">Bob</font>
<br>
<br><font size=2 face="sans-serif">Actually even most epoxy paints are
the same, that is they have a resin which is a solid at room temp. If you
are referring to the old KB epoxy, that too was a solid, but a blend of
different evaporating solvents made it appear differently. You will find
Concept about the easiest paint to spray.</font>
<br>
<br><font size=2 face="sans-serif">The isocyanate hardener can be a health
concern, but that is for people who spray this for a living. The average
Pattern Dude inhaling one planes worth is not going to die (immediately).
Try not to breath it.....position yourself as best you can away from the
overspray....little dust masks do no good, contrary to popular belief.</font>
<br>
<br><font size=2 face="sans-serif">Good spraying is temp sensitive, so
be wary of that.</font>
<br><font size=2 face="sans-serif"><br>
<br>
<br>
Gray Fowler<br>
Principal Chemical Engineer<br>
Composites Engineering</font>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>Bob Kane <getterflash@yahoo.com></b>
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<p><font size=1 face="sans-serif">10/20/2005 05:48 PM</font>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">Gray E Fowler <gfowler@raytheon.com></font>
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<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td><font size=1 face="sans-serif">discussion@nsrca.org, discussion-request@nsrca.org</font>
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<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">Re: PPG Concept curing question</font></table>
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<br>
<br><font size=2><tt>I guess what I did not expect was the paint gassing<br>
off and turing solid without the hardener. Again,<br>
using epoxy as the standard, the resin and hardener do<br>
not "dry" by themselves (at least not in a few hours).<br>
<br>
Thanks for the explanation.<br>
<br>
--- Gray E Fowler <gfowler@raytheon.com> wrote:<br>
<br>
> Bob<br>
> <br>
> Dry and cure are different terms. Paints "dry" which<br>
> means that the paint <br>
> resin is a solid at RT and it is cut in a solvent.<br>
> When the solvent <br>
> evaporates, a dry film of resin, pigment and filler<br>
> is left behind. The <br>
> Concept resin is exactly the same...BUT the finished<br>
> product adds a <br>
> isocyanate curing agent which actually crosslinks<br>
> the resin polymer. PPG <br>
> Concept drys first to the touch then continues to<br>
> crosslink react or <br>
> "cure". The stuff that is dry in the can just had<br>
> the solvent evaporate.<br>
> <br>
> Try this experiment.....mix the Concept per the<br>
> instructions, spray your <br>
> enitre plane. After it is "dry" (1/2 hour) wipe your<br>
> plane with acetone-it <br>
> will wipe off. Spray your entire plane a second time<br>
> but let the Concept <br>
> dry AND cure then wipe it with acetone.....and it<br>
> will remain. You can do <br>
> this with a test coupon instead of using your plane,<br>
> but the results are <br>
> not as rewarding.<br>
> <br>
> <br>
> <br>
> Gray Fowler<br>
> Principal Chemical Engineer<br>
> Composites Engineering<br>
> <br>
> <br>
> <br>
> Bob Kane <getterflash@yahoo.com> <br>
> Sent by: discussion-request@nsrca.org<br>
> 10/20/2005 02:51 PM<br>
> <br>
> To<br>
> discussion@nsrca.org<br>
> cc<br>
> <br>
> Subject<br>
> PPG Concept curing question<br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> I am using PPG Concept (DCC) paints for the first<br>
> time. I had innocently assumed since this was a<br>
> two-part paint, it cured much like epoxy. But after<br>
> working the stuff for a couple of weeks I noticed<br>
> the<br>
> unmixed paint in the empty cans was "dry". So, my<br>
> assumption is the paint will "dry" on it's own, but<br>
> would not have the durability of properly mixed<br>
> paint?<br>
> The hardener gets all the molcules link arms and<br>
> form<br>
> a tougher material? Thanks in advance.<br>
> <br>
> Bob Kane<br>
> getterflash@yahoo.com<br>
> <br>
> <br>
> <br>
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<br>
<br>
Bob Kane<br>
getterflash@yahoo.com<br>
<br>
<br>
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