stunthanger.com
Building Tips and technical articles. => Paint and finishing => Topic started by: Serge_Krauss on May 18, 2016, 10:34:28 PM
-
I finally flew my profile stunter with my P-Force wing. While trying to replace the overflow vent cap after fueling with very old 5-11-11 Powermaster fuel, some fuel ran down the bottom fuselage side. Although I wiped it off immediately, this was the result. This was clear butyrate, over clear with "fade-proof" red ink pigment, over gold, over West Systems epoxy/fiberglass. The Brodak butyrate finish had been gassing off for about two to three months. I will re-direct the overflow exit. - SK
-
How much time before this happened? I usually don't fuel or fly a plane for several weeks after doing a clear coat. H^^
-
Add a piece of hose on the bottom, long enough to get overflow clear of the fuselage. Leave it in place, and use one of the DuBro plastic plugs to seal it off after fueling. Hold the plastic plug between your teeth while filling, so if you get to the handle and find it still there, you'll know you didn't plug the overflow. This also prevents conversations while you're fueling, which is good! ;D Steve
-
Doc, it's been months since I doped the fuselage. The damage happened immediately.
I didn't have eight final clear coats though. I had a couple coats of clear over the fiberglass, and then three coats of gold (for coverage), three coats of clear with "fade-proof" ink pigments, and two or three of clear without pigment. These were all Brodak butyrate. The immediate dissolution down to the glass makes me more than hesitant to characterize this clear as even fuel "resistant." This has never happened to any of my planes before. The original P-Force with Brodak "candy" red and a similar coating sequence (no fiberglass though) showed some slight discoloration in a splatter/flow pattern near the outboard tip after flying and being distracted before cleaning, but there was never any damage near or on the fuselage, the pieces of which I still have.
I will certainly extend and/or divert the overflow tube. I'll have a bit greater test next time, when I fly without the muffler to see whether it flies well enough to exchange the boat anchor for a tongue muffler (lost mine!).
SK
-
I'm beginning to think that one of the urethanes, even a single part type, just around the nose and tank area might be the answer. I've been looking into the one DuPont product that is a two part clear, but comes in small quantities, and can be mixed up in small amounts, for just this purpose. If you have a crash, you will be sanding the whol thing off anyway so repairs should be too much of an issue. Nason is the name I believe and is supposed to be thinned and ready to shoot after adding catalyst.
Type at you later,
Dan McEntee
-
Thanks, Dan. Believe it or not, I hadn't thought of doing that for the engine area. 'sounds quite doable!
SK
-
You can mix two part polyurethane in as small a quantity you want. I have mixed as little as 10 grams at a time for repair work. Inexpensive automotive types such as Omni works well for this. I use an eye dropper and a gram scale mixed directly into an airbrush 1 oz. bottle. Cheap lacquer thinner such as type sold at Lowes works fine for clean up. Omni is a PPG product and is sold at most automotive paint shops.
Here's one available from TCP Global that would be fine also.
http://www.tcpglobal.com/RSP-KIT-RC4200-QT.html?gclid=CIf555vT58wCFU1gfgodSBUB1w#.Vz58Qf32Zpg
If you don't try it you'll never know for sure. Use the correct protective mask.
-
Thanks, Mike!
-
I finally flew my profile stunter with my P-Force wing. While trying to replace the overflow vent cap after fueling with very old 5-11-11 Powermaster fuel, some fuel ran down the bottom fuselage side. Although I wiped it off immediately, this was the result. This was clear butyrate, over clear with "fade-proof" red ink pigment, over gold, over West Systems epoxy/fiberglass. The Brodak butyrate finish had been gassing off for about two to three months. I will re-direct the overflow exit. - SK
Hi Surge,
Man it hate it when that happens! Lightly sand it down and repaint the area, then spray the nose area with a high grade PPG omni spot clear. This works really well and should help keep it from happening again. When I first started using this paint, it seemed to stay clear and not yellow. Maybe GlassKote will do the same but I've never tried it.
Later,
Mikey
-
Thanks, Mikey and the reat. I've flown it again with a little further damage, despite precautions that prevented any direct spillage. I will try the fuselage refinishing technique.
SK