The next step is to cut a piece of silk to cover the wing. I cut it about an inch or so larger so I'll have something to pull on when it comes time to stretch the silk. I cover the wing with the grain/threads of the silk going span wise.

After I have the silk in place, I take a spray bottle of water and spray on the silk. This helps to keep the silk in place while I apply the nitrate dope to attach it to the wing. I then stretch the silk to make it tight and then apply nitrate dope to the perimeter of the wing.

After applying the dope, I keep stretching the silk as the dope is drying. I still use t-pins to hold the silk in place around the tips.

To avoid warps, I silk the top and bottom of a panel and then do the other panel the same way. The excess silk is easy to sand off after the dope has dried.

What Larry says is good stuff.  My experience is with Esaki silk, some packages which I bought for $1.95 many years ago.  If I am doing a diesel powered airplane, I go nitrate all the way. If a glow airplane I go butyrate all the way. I put enough non tautening dope on all surfaces which will touch the silk to make the surface shiny.  If you don't do this, the open bays will get shiny and the wood will still show the silk grain because the dope will wick through. I put the silk in place, then wet it.  I get it really wet, which is another reason to do a good dope job on the wood. The silk can be stretched tight and the water will hold it in place. 

As Larry says,  keep the weave straight.  Silk is very easy, but you must be patient and demand perfection.  Once it is in place, I go around the edges with dope thinned at least 70% thinner.  This will adhere to the underlying dope, and blush.  If it is a constant chord wing I will demonstrate my expertise  by starting at the bottom trailing edge, going around the leading edge, not sticking to the leading edge, and back to the top trailing edge. I stick it down there and on the ends.  Keep everything wet, and hang the wing vertically so the silk dries evenly and does not pull in a warp.

Once dry, I brush on several coats of tautening dope, thinned 70% thinner.  This will go through the silk to start, but will not make the puddling effect.  I do a couple of panels, then turn over and do a couple of panels.  Once most of the pinholes are filled, I go to progressively thicker non tautening dope until it shines to suit me. 

If I am going to use tissue numbers and letters, I put them on before going to the thicker coats, just sticking them down with thinner. This presumes you are doing a clear or tinted finish.

  Larry B, how much do you thin your dope that you apply to the silk?
 My wing is ready for some clear, and I would like some thoughts/suggestions on this.

  Oh, I would like thought's/ suggestions from thr other men on this also..
 Thanks.

 One more P S the dope that I am gonna use is Tautening Randolph clear for the silk..

For applying the silk, and the first few coats with a brush, I thin butyrate about 65 to 70%. That will be thin enough to keep it from running through, and if it does there won't be enough solids to make a blob. The 5mm Dharma silk will be filled after about 3 coats of this mix. Since I do the complete finish with a brush, I just continue brushing clear dope at slightly thicker until I get a nice sheen. At that point I wet sand everything with 400 grit. I then apply a few more coates of clear dope thinned at least 60%. If it looks good at this point, I go ahead and do the color coats with the color thinned at least 60% also. I then go with a couple of coats of clear again thinned at least 60%. If you keep your dope thin it will keep brush marks to a minimum and I usually don't even sand the plane except for that one time. When it is all done and for a super finish, wet sand with 600 grit wet, and then rub it out with Dupont white rubbing compound.

When I do the trim colors, I mask off for the color, and use a small brush to paint clear along the edge of the tape to keep the colors from bleeding under the tape. After applying the color, and before removing the tape, I give the trim colors a coat of clear. That keeps the colors from smearing when applying the overall clear coats later on. Some colors won't smear, but others will without the clear on them first.

I use a good quality camel hair brush for all doping, and don't ever brush the dope more than three strokes per brush load of dope.

There are many tricks to getting a good finish with a brush that I think you just have to learn by doing. I have been brushing all my planes for the last 16 years, and just do a lot of things without really thinking about it.

I use Randolph dope with the exception of Brodak's crystal clear. I get mine from Tex-Air in Fort Worth. Any aircraft maintenance supllier should be able to get it. All Randolph colors are non-tautening, I called and asked.

If you want areally light finish. First cover with mylar, just like the competition Free Flight guys do (I use a thinned down impact adhesive on the ribs etc and after it is dry, I put on the very very thin mylar, you need an iron or heat to make it stick. Then cover with silk as described above. One coat of shrinking dope (suitably thinned) and you are there!
  You don't need lots of layers to seal the silk, the mylar doe that. Finish to your taste and you have a very strong lightweight finish that is far stronger than silk alone.

Regards,

Andrew.

If you're talking about my method, silkspan works the same.

I would say that the difference between silk and silkspan is really pretty close. I have finished many planes with both, and I would say that the new silk like from Dharma, is a little lighter finish because it fills so fast with dope. I don't use any filler in my finishes, just clear dope all the way out to the color. The silk seems to take less coats to get to where I can go to color.

My experience has been that silk takes a couple more coats of clear to seal than silkspan. 

I'm gonna have to try that stuff some day, (polyspan). 

Clint

I hear people say not to use it on wing tips.  What say you ? 


Dan

Thanks much !

Clint

I hear people say not to use it on wing tips.  What say you ? 


Dan

The first time I used it, I fell in love with it.  If you put the dope on heavy on the tips, an iron with ample pulling and holding till it cools works pretty good.  If you sand it too much, it fuzzes real bad.  Make sure you put numerous coats on before sanding.

John

The first time I used Polyspan I didn't attempt to cover the tips but instead used strips of silk span. (and the second time to) Then someone (Wish I could remember who) said he got it to go around the corners with a little finesse........

On my Ringmaster I tries it and it is just like covering with monocoat.

Heat stretch, heat stretch, etc. and voila! It has gone around the corner.

I have a couple pictures but I don't see how to add them. Someone want to help me?

Thanks in advance, Jerry

Hi Bill,

Thanks for the reply. I figured it out on the OT page.

Cheers, Jerry

PS: This RM has been sitting around for over a year waiting for paint..........and it is fairly light, just under 14 oz. with a few coats of clear, fillets, etc.. Add tank, engine, prop, wheels and paint for the final weight.

That looks great Charles.

I tried the Larry Renger method of putting SLC over poly span on my modified Skyray. Man, that's a job. Didn't turn out as well as I expected it to. I guess I have to learn how to pull the 'L out of it on the corners. Otherwise it looks fine.

Cheers, Jerry

For places to get all your dope and thinner call either Aircraft Spruce and specialty or Wicks Aircraft Supply . They will have all you need ,but they only have quarts. If you want smaller quantities Brodack paints are  all Randolph,I am not sure about SIG dope. Good Luck Chuck Stanley.

When you put that first coat of dope on silk over an open frame do you spray it? brush it? What is your technique?