I need to slightly thin some 30 minute epoxy to make glassing a wing center
section easier. I know that the high water content of isopropyl tends to
weaken the epoxy, so which would be best? Denatured ( ethyl with methanol
added ) or straight methanol?
Mark D. Fain
On Tue, 28 Jun 2005 10:16:49 -0400, "Mark D. Fain" wrote in
If you're just fuelproofing or otherwise "painting" the epoxy on,
I'll bet you couldn't tell the difference between these two.
I'd use whatever you have most of on your shelf.
If you're trying to get epoxy to flow a bit and want to
retain much of its strength, you can heat it. It
doesn't take much. It will flow like water, then
set up very, very quickly. Check for drips and
clean them up quickly--you've only got a small
window of opportunity to do so.
I don't use alcohol at all,
spread the stuff on,
use a heat gun to GENTLY warm the epoxy up a LITTLE, and it will flow and soak
through the fiberglass into the wood VERY well
use one of those fake credit cards you keep getting in the mail as a squeegee to
force the epoxy through the cloth and to get any air bubbles out,
once you can clearly see the wood grain through the fiberglass, the glass is
fully saturated, and the epoxy is down to the wood.
then use a roll of TP or paper towels to mop off the excess epoxy
you may want to go back later and fill the mesh with something later, but
leaving gobs of excess epoxy on the surface adds a LOT of weight and contributes
very little if anything to the strength.
this method works for me,
Bob & group -
Please excuse a newbie question, but I have seen this before and not
understood it very well. Do you mean using the whole roll of TP/towels
like a paint roller? Is there some way to use the absorbent without it
sticking to the epoxy & mixing with it? Is this done in addition to the
credit card squeegee?
Tnx - LeeH
Don't add alcohol to epoxy. It screws it up. I mean, you use epoxy because
it is supposed to be strong. If you don't care how strong it is, use water
based polyurethane paint. It works well as a fiberglass binder too.
But, as Marty suggested, to thin epoxy, the best thing to do is to use a
slow curing epoxy and then heat up both tubes in warm tap water. That will
thin it to good brushing consistency and will not significantly weaken its
strength. It does speed up the curing time, so keep an eye on it.
That is exactly what I do, use it like a paint roller.
move pretty fast, and keep stripping off the outside layer.
It doesn't take NEARLY as much paper as you would think, particularly if you
use a "credit card" or old playing card or something to squeegee off most the
excess before you mop up the drips.
the epoxy will tend to act almost like heavy oil or thin grease, and the TP or
paper towel will pretty much skate over the top without sticking
that you work fairly quickly, and don't let the epoxy get tacky before you start
Another good thing to do is to heat the parts to be glued with the old
heat gun, rather than the epoxy itself- this does not shorten the pot
life of the mixed epoxy, and really makes it flow into every crack and
soak into the wood as soon as you apply it.
- I'm here to help - Paul
Go to the drug store and get some 99% alcohol. Last I bought was about
$3 per pint. I have been using this for years with no problems. I also
thin Epoxy finishing resin with it for glassing / reinforcing Quickie
500 pylon racer wings .Powered with Nelson engines they go over 150
mph. Holds okay on these.
On Fri, 01 Jul 2005 20:54:45 GMT, "Jim Slaughter" wrote in
I presume that if you're intent on thinning epoxy, it's going to turn out
to be used for a paint-like purpose.
I doubt that any of the commercial expoxy solvents would be any
worse than the home brews we've been recommending. :o)