Hi All:
Would spraying a silkspan covered airplane with a coat of clear dope add anything to the strength of the old silkspan?
I patched some holes and painted the patches but I am wondering if I shoot a coat dope on the tissue, if that would help avoid holes from being punched through the tissue when while taking off or landing from a grass field.
I think that this Magician was built in the 60's or 70's.
One bright note was that I replaced the McCoy .35 with a 1972(?) Fox .40 Stunt and the the Fox started and ran on the first flip after hanging in my attic for over three decades!. Some times one gets lucky. I had only bench tested the Fox before I mounted it in the Magican circa1973.
Tia,
Frank
The silkspan itself contributes very little to the strength of the finished covering; it mainly provides a uniform surface to hold the dope which is the real strength of the finished covering. I think that the problem you will have with a 40 year old cover job is getting it clean enough to hold the new clear coats. Oil is probably the most problematic contaminant along with silicone, wax, etc.
For cleaning I would use Windex first per Phil Granderson's finishing article, then use an automotive paint cleaning solvent such as Sikkens M-600 or Poly-Fiber C-2210 (available from Aircraft Spruce & Specialty, among other aircraft suppliers.) When you get to the point of using the paint cleaning solvent do the old "Karate Kid wax-on, wax-off" routine, using a rag soaked with solvent in one hand and immediately wiping it dry with a clean rag in the other hand. Do not just let it dry by itself as the wet solvent will float the contaminant to the surface & then when it dries most of the contaminant will still be there.
Then don't handle the airplane with dirty or sweaty hands as you will undo the cleaning you just did. Sweat, as you no doubt are aware, has oils in it. Also, for rags I only use clean cotton tee-shirt material which you can buy by the box at Home Depot or Lowes, or from an industrial supplier of rags by the 50 lb. box as I do for my finishing projects (full-scale and models.) Additionaly, I don't re-use the rags or wash them...it just isn't worth it when you consider all the labor you have in a project whether it be a model or full-scale airplane.
It is probably worth a try if you just want to get something to fly, and it may work out well. If you get the old cover clean enough to hold the new clear then you could apply 4 or 5 coats of fresh non-tautening butyrate clear with some plasticizer added (I use Dave Brown's "Flexall" per the instructions on the bottle.) This will add some strength to the old cover.
Topic: Spraying a 40 year old with clear dope: good or bad idea? (Read 1331 times)