I'm painting a model with latex paint -- first try. The latex isn't fuel
"proof" for glow fuel, so I need to cover it with a clear coat. I was
thinking of using Polycrylic (thinking that was a water-based polyurethane
since its cans are right next to the oil-based polys at the store), but
I've found out that Poly c isn't even really fuel resistant. So, I was
wondering if anybody knew of any brand names for any easily available
water based polyurethane that can handle 10% nitro. I've tried looking at
Home Depot, a paint store, and a local hardware store for Verathane, but
wasn't able to find it.
Ted shuffled out of his cave and grunted these great (and sometimes not
so great) words of knowledge:
MinWax Polycrylic (waterbase polyurethane ) is fuel RESISTANT WITH THE
1. Do not expose the poly to fuel residue for a MINIMUM of 7 days.
2. Do not let the residue remain on the plane longer than 4 hours. (I
suggest cleaning the plane off after about 2 - 3 hours.) After 4 hours
the residue will begin to soften the poly.
Waterbase poly WILL NOT yellow with age, so it is safe with whites and
other light colors.
If you want a fuel PROOF clear coat, use Ultracote Clear and let dry for
a minimum of 72 hours. Lustercrap will also work if you want to fight
with the spitting it usually has.
You can also try an ACRYLIC clear ENAMEL (Krylon, Dupli-Color, etc. )
HOWEVER, I strongly suggest doing a test panel 1st. Let the clear dry
for 24 - 48 hours, then put it in the exhaust stream of a running engine
for about 5 - 6 minutes. Let the residue remain on the test panel
overnight, then clean it off. You will know immediately if it is fuel
proof or not. I have had excellent results with Dupli-Color "Truck &
Van" paint in colors.
If you decide to try the Dupli-Color, read the label carefully. They
have acrylic enamel AND acrylic lacquer. You can put enamel over
lacquer, but not the other way (the underlying paint will "craze".)
Check RC Universe
Discussions area/Tips & Techniques. Do a search on Campy. I have done
some experimenting with various clear coats and my results are posted
there, HOWEVER, I DO RECOMMEND DOING A TEST PANEL FIRST before commiting
to the plane.
Hope this helps.
Contrary to popular belief, Minwax Polycrylic is NOT polyurethane! Read the
can - the only places the label mentions polyurethane is where it says for
floors and other tough applications you should use Minwax fast-drying
polyurethane (oil-based) INSTEAD OF Polycrylic.
I've used both Minwax Polycrylic and Flecto's Varathane (both are
water-based) on cabinets and shelving for over ten years. I like the color
Polycrylic gives to red oak, but glow fuel dissolves it immediately even
after years of curing, while Varathane, even on my engine test stand, holds
If you can't find Varathane, read the labels on cans of other water-based
coatings and check that it really is "polyurethane", and not simply saying
that it's not as good as polyurethane.
I have used Minwax Polycrylic with good results up to 10% nitro.
Spray one coat and let it cure out for a week then put on a second coat. A
week later use some soft spread auto wax on it carefully and go fly.