Just for clarification because my original post was quoted in the above message, the Legal Eagle had a secondary acrylic color added
to the original Polyfiber silver coat. Acrylic primer was applied prior to the topcoat and there was excellent adhesion as proved by tests conducted a couple of years after the topcoat was added. The acrylic primer appears to adhere tenaciously to whatever surface it is applied to and I don't anticipate any future issues with the acrylic paint over the PolyFiber silver.
By the way, there are no "Stitts" coatings anymore, the system is under the PolyFiber label and STC.
The Fokker D.VII has a total acrylic finish, primer followed by topcoat, no PolyFiber or Stewart finish products were used. The admonitions about not mixing systems is primarily for certificated aircraft because their finish must meet TSO specifications. Within the experimental/ultralight community we are free to apply/experiment with whatever finishes common sense permits.
On two earlier projects I used "experimental" finishes with good results. One had latex (as it was called back then...) base followed with automotive enamel. The other had latex base topcoated with Rustoleum enamel sprayed with a gun. There are several ways to achieve satisfactory results on light, slow aircraft without spending a ton of $$$$$s. Both of those aircraft had PolyFiber fabric adhesive.
Last edited by Sam Buchanan; 11-28-2015 at 11:10 AM.
Sam, Excellent clarification on your finish work. Thanks for your input.
Some clarification about my previous post that mentioned swirl-cracks from rattle-can paint. This was on standard modern fabric on an UL built in the late 80's. The builder applied the full list of PolyFiber coatings. The trim paint I applied in 2002 was RustOleum acrylic; so oil-based paint over oil-based PolyFiber, sanded a bit. Swirl cracks only appeared on the wings, nowhere on vertical surfaces. I didn't know the reason at first, so painted it again awhile later-- same thing. In asking around, several lads confirmed the cause to be expansion/contraction of the fabric. On tail surfaces there isn't enough square area to make it stretch enough. I'm sure wood, fiberglass or metal surfaces don't have this problem.
Last edited by flyrgreen; 11-28-2015 at 07:31 PM.
I used this process on my Little Wing gyroplane with very satisfactory results. The paint has been on the plane for a couple of years now, and I'm satisfied. As you say, not a $3000 paint job, but it serves the purpose. Had to replace a small piece of fabric after the initial application, and the repair can't be distinguished from the original part.