I do silk & dope all the time.

Just like you, expect I use butyrate dope.  It seems kind of sagged until I get up to 6 or 7 coats, then ti tightens OK.

Your procedure seems OK.  Remember, the silk doesn't shrink, just the dope.  So if it was wrinkle-free to begin with, is should go back to wrinkle-free when the dope shrinks.

I've never been a fan of nitrate.  I need all the "fuel proof" I can get.  Maybe "fuel-resistant" would be more honest.

So do I wait for the dope to cure some more, or put more on?  The weave looks completely filled to me already.

Mike,
I have had similar problems with nitrate over silk (I only use Sig Supercoat clear buty now which is taunting). If you used the non-taunting type, it will take time to finally pull tight. I would let it gas off for a week and if still wrinkled, then go with a coat or two of taunting buty. You will have to eventully go to buty anyway, so might as well do it now.  I tried the thinner and heat technique with little success. Only thing that really worked was the taunting dope. As said eariler, it's only the dope that really shrinks not the silk.
Jim 

 Just a suggestion, I use silk over mylar, the very thin type used by the freeflight competition guys. You heat shrink the mylar and then put the silk on top. No sagging and no need for lots of dope coats (the covering is airtight). The big advantage is that the resultant covering is lighter than the conventional silk covering.
  The drawback is that a lot of folk find it difficult to do the mylar covering, I don't know why! I don't aspire to the elite finishings though.

Regards,

Andrew.  

Andrew,

Do you use dope to apply the silk to the mylar, or is another adhesive required for adhesion?

Thanks.

I'm using Randolph 210 which is labeled as taughtening.

I also use Dharma silk and haven't had any problems, I use the lighter (cheaper) stuff. Randilph makes Butyrate in both tautening and non. Their colors are all non tautening, called Randolp directly about the colors. I apply the silk dry, applying dope only around the edges to get it to adhere. After I get all the wrinkles out, I spray the silk with water and after it drys, start putting thinned nitrate over it until filled and before applying the color, two coats of butyrate clear.

Hi Kim,
    Very late in the day, I noticed your question. I use the dope to stick the silk to the mylar. I use thinned down contact adhesive to stick the mylar to the structure. Paint it on and allow to dry. Ironing on the mylar activates the adhesive.
  Sorry for the huge delay in responding.

Regards,

Andrew.

Just curious, after we drape the wet covering (silk pr silkspan) over the structure, we ARE pulling it tight while doping it down, yes??  You can never get it too tight as long as both sides dry at the same rate and time.

Big Bear

I put silk on sopping wet.  So the structure has to be well doped.  It should be anyway, or the dope will go through the silk, and the open bays will be shiny while the silk grain still shows over wood.  With the silk really wet, it sticks to the wood and will stay in place once you get it pulled tight.  Then dope around the edges.  Cover both sides of the wing, keeping all silk wet the whole time.  Then hang the wing vertically to dry, so that the top does not dry faster than the bottom and cause a warp.

I have been migrating to silk for the past 4 airplanes.  I currently am using 5mm but will order at least 8mm the next time.  The biggest reason for that change is that it now takes me 8 to 10 coats to fill and get the silk tight.  I hope to improve that with thicker silk. 

I put the silk on wet and pull it tight.  While drying, I use a hair dryer to dry and shrink it.  That produces a reasonably tight, nice looking cover.  As soon as I put dope on however, it sags and gets wrinkles.  It takes 8 to 10 coats to get back to where I was.  But I love the look and strength of the silk.

I use Randolph tautening dope until the color for the last few coats.  I have had the dope "warp" the wing but some wet and microwaved towels draped over a straightened and secured "in place" wing, fixes the warp and I have had no trouble with it warping back to the "undesirable."

I read all these posts with a great deal of interest and have a few questions, firstly how much heavier is silk than either silkspan, polyspan or plastic film such as monocote which I don't like using due to the amount of heat needed to do a good tight finish that doesn't get loose in the sun mine always seems to especially the ARF Nobler I have, or the film Tower sells which is cheaper than monokote anyway not yet tried it but I have some I will use on a Peacemaker I am building, secondly where do you get good quality silk, I have used nylon bought from hobby stores by the sq yard years ago and it seems it is no longer available, thirdly when I used nylon I only had to put on 5 coats of 50/50 dope and a sixth coat of 75% thinner 25% dope even less coats if I was going to coat with colored dope.
 My main interest is where do you get the silk, I have been to Bangkok a couple of times but because I didn't know what to get I didn't buy any it seems there is alot of very different grades, weaves and weight to silk if I know what I am looking for when I next go back with a sample of silk it is so cheap there, the first time I went there I bought a complete bolt of patterned white silk to use as window treatment for about what I paid for a nights stay in the hotel I was staying in.
 So could someone please tell me where to buy silk from and what weight and weave etc., to buy for .15cu.in. through .46cu.in. models, I have a Strega kit but am still debating whether to build it or not I have a feeling the pull of a S.T. V60 will be too much for my healing shoulder.

  Thanks Y'all

I've just found an advert for esaki 5mm habotia silk, and it states that it is not pre-shrunk! Maybe it does only shrink once?

Cheers

Like silkspan. Silk has a grain. warp and weave. You want grain to go across the wing from wingtip to wingtip.

Does the "grain" of the silk run across the bolt, or with the bolt? I've looked hard, and can't determine which way it runs.

Brian