jlandis

I am in the process of covering a GWS corsair with Silkspan/ minwax water based polyurethane. the project is going well on the smaller parts butI want to throw a couple of questions out there.

1. Wet vs dry- I have read some posts that recommend wetting the silkspan with water and then applyinging to the surface followed by applications of the palyurethane. I have tried both ways- applying the silkspan dry followed by the poly directly to the dry tissue. Even though the recomendation is to apply it soaked with water, it seems to adhere better when applied dry with the poly only. Any comments on this?

2. Large surfaces- what is the best way to apply to large and irregular surfaces like the fuselage? One big sheet and hope to get the wrinkles out, or take it in sections. And if one does sections, overlap at the edges or try to butt the edges up to one another?

3. Curved edges- What is the best way to get around curved edges? I have tried stretching it out to the edge and then cutting into the material, overlaping it on to the edge. Works ok but the edge is still heaped up a bit. And it does not sand very well. See picture below

This is an olde plane that I am rehabing. I have a new TM400 that is unfinished and I want to get this process perfected prior to stating on the TM400 so any comments would be appreciated.
J

mmattockx

Well, I've never used Silkspan with poly paint, but I have done a few with dope, so I will give it a shot.

1) The wet method is what I used with dope. It works great for that, but the dope is totally unaffected the water. Since your paint is water based, it may not work the same. I say if it is sticking better dry, stay with that. The thing that the wet application does is it lets the silkspan drape better over curves and such. You still can't do a serious compund curve, but gentle ones can be done. I used to use a cookie sheet with maybe 1/4" of water in it to wet the silkspan. You get your sheet cut to size, then dip it through the water just like old time wall paper technique, then lay it on the airframe and stick the edges down with dope/thinner or just thinner. One other thing that the wet method does is it shrinks the Silkspan as it dries, which is useful over open bay areas but not of much value on sheeted stuff.

2) I say sections, it is just too hard to get it all straight in big chunks. I liked using long strips to cover the fuse, running the long way. You overlap them a bit (1/8-1/4") and then you just sand the overlap bump smooth after a coat or two of paint. If you are careful with the filling/sanding routine the seams are impossible to find and it looks like one seamless piece of covering was used, especially after the color is on.

3) I am not sure what I am looking at in the pic. Is that a wing fillet? For complex surfaces, I always used smaller pieces and then sanded off the overlap after. It is a lot of time and effort, but the final results are outstanding.

How do you like the Minwax over Silkspan? I have been considering trying the water based paints on a future build with either Koverall or Silkspan, but hadn't heard much about it yet.

Question for the other poly users out there - can you spray poly paint over nitrate dope? I have a partly finished Kadet Sr. that has Koverall and dope on it but no color coat yet. If I can use Minwax over the nitrate dope that would let me paint without all the nasty fumes and stinking the house up.


Mark

vicman

My Feedback: (10)

My question is why would you do this to the GWS Corsair? If you buy the un-painted one you can have any scheme you want with very little added weight by using water based acrylic from wally world shot thru an airbrush.

jlandis

As I stated this is a rehab of a prepainted/ crashed multiple times Corsair. So it needed an overall finished surface to cover up the patches fillers epoxy joints. I have read the method gives a great finish. In addition, the wings are weak, the ailerons flimsy as are the tail feathers so this strengthens them quite a bit.

WacoNut

I have used Minwax PolyC over Sig Koverall with great results, I covered a Sig 1/4 scale Cub and a Jack Stafford Aircoupe in this manner. I have never used Silkspan so I cannot comment on that. The Sig Koverall provides alot of strength.
Anthony

vicman

My Feedback: (10)

Point taken.

Jimmbbo

Am likewise concerned about the dilution effect of using a water based paint, but I like doing silkspan damp because it forms easier over curved surfaces.... I think that the s'span will adhere with waterbased paint if it is only damp, not wet. I spray the silkspan with a spray bottle, lay the piece on a towel and press another towel gently over it to absorb almost all the water, leaving barely damp silkspan.

For fuselages, I use the largest piece I can to cover the most of the fuselage, then progressively smaller pieces to cover the remaining parts. If you really want to get detailed, you could dupliate the panel lines and overlaps, but that's a bit too much work for me

With compound curves, the only way to cover the piece is to use small pieces, fit as well as you can, then prime and sand when dry...

Please post pics if you get a chance.

Cheers!

Jim