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Building Tips and technical articles. => Paint and finishing => Topic started by: Chris_Burgess on June 28, 2011, 10:55:14 AM
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I am currently about to start an el Diablo and I want to do it with silk... Now I know I'm probably asking for trouble, but the prospect of doing such a marvelous airplane in Silk is too exciting to pass up. This will be my first Silk cover job, I have done silk-span in the past but I'm hoping there are some out there wiser than I that have some suggestions for a first time Silker!
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I'm sure others will chime in with their experience....JMHO....put on at least 3 coats of clear dope (for me, not nitrate) and sand lightly with 600 paper..wash your silk in bath tub to remove any impurities and rinse several times
in cold water..squeeze out excess water...lay silk on wing (making sure grain runs spanwise) and gently pull silk taught in all directions....I prefer to use 50/50 dope and thinner rather than all thinner as the "glue" to adhere it - others will say to use only thinner...spray the silk with a water bottle until just saturated and apply dope to all the
edges only being very careful not to put any on the ribs and start streching the silk until it is very taught and apply more dope rubbing it down with your fingers to seal the edges ...I wrap the silk around the trailing & leading edges and after it dries, very carefully trim the excess away witha razor blade and use some 200/400 grit paper to smooth
the edges and the apply more dope to seal that silk edge. After all surfaces are applied and dried, brush/spray on dope and silk will shrink more and be very taught and then apply dope coats until grain is filled...being very careful not to sand on ribs very much until you have alot of dope on silk so as not to sand through to ribs. Hope you end up with a "20" point finish !
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I use Esaki silk. it is very thin and can be had in a number of colors. It is available from free flight suppliers such as FAI Supplies, Aerodyne, MicroX, Peck Polymers, etc. It is somewhat expensive compared to Thai silks, which I have no experience with.
First make sure that all surfaces which will touch the silk are well doped and shiny. On the El Diablo, I would cover the top and bottom of the wings with separate pieces. Make sure you have the grain of the silk running spanwise. Cut out a piece giving you an inch or so all around. Lay it down on the wing and spray it soaking wet with water. Carefully arrange it, keeping the grain lines straight and no wrinkles. It is not hard to do, but requires attention and patience. Go over the places you want it to stick with thinner (I actually like very thin dope.) Trim the edges with a razor blade. Now do the same with the top of the wing. Keep all the silk wet until finished. When finished, hang the wing vertically so that both sides will dry evenly.
On the fuselage, I would do very much the same. Silk goes round curves very well. I would cover the stab, elevator, and rudder with either silk or similar color tissue.
Once the silk is dry, brush it with a mixture of tautening butyrate; 30%dope, 70% thinner. I brush about three bays and turn it over and brush three bays on the other side. There will be run through, but it won't show with dope this thin. After about four coats, the silk should be mostly sealed.
Now cut out your numbers out of tissue. I recommend Spectra black. Stick the numbers down with thinner. Then switch to non tautening butyrate and go with a thicker mix until it is shiny to suit you.
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I do love a good natural color silk job, and I am looking for something similar to that with the el Diablo. Thank you also for the tip with the Japanese Tissue, that thought never occurred to me, I have a really cool design that I've come up with in my head and just need to get it onto paper and instead of paint I'll be using the Tissue. I will be sure to post pictures when the airplane is finished! As I said the plane is still being planned... but I've got a nicely blackened Fox .35 to bolt to the nose, the wood is here the plans are in the basement in duplicate and the board is finally almost clear of the several other projects that are being finished.
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Does anyone else have fading problems with jap tissue? I have a 30" vintage rubber model on the shelf in my office, it hasn't seen a lot of sunshine, and doesn't get the sun on it on the shelf. It was red blue and yellow (genuine jap tissue), the blue is now a pale grey, the red is almost white! The main colour, yellow has faded too! I may well re-cover it in lightweight Modelspan (rag tissue) I don't recall it fading that bad ???
Cheers
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I get all my silk from Dharma Trading Company and have been using it for a couple of years. I have been using nitrate to seal the framework before covering and also to get the silk applied. I put the silk on slightly moistened with a spray bottle, helps to keep the silk in place. I then start putting the nitrate to get the silk onto the wing.
I cover both bottom panels and then cover the top. After all panels are covered, I spray a fairly heavy coat of water on all surfaces and the put aside until completely dry.
I like using the nitrate as it seems to glue the silk down better, but that's just me. After the wing has dried from the water, I start spraying thinned coats of butyrate dope to seal and shrink. Doing all panels at one time, seems to help keep out warps.
Sig silk at the LHS is now 25 bucks a sq yard and I get the silk from Dharma for about 4 bucks. Personally I can't tell the difference. It seals and shrinks the same as the Sig. I've never had to wash any sizing out either.
That's how I do it.
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Get a copy of Dave Platt's covering DVD back to basics, B 2 B. It covers doing a perfect silk job. ;)
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Get a copy of Dave Pratts covering DVD back to basics, B 2 B. It covers doing a perfect silk job. ;)
Source ??
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Go to Dave's website, www.daveplattmodels.com. The video is B2B-1 Back to Basics. Hope this helps. Mike
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I know I'm rehashing a pretty old post, but I finally got around to doing some silk on the el Diablo and thought you'd like to see the preliminary results. Obviously I have a LOT more work to do, but right now it is a start, and as amazing as it may seem, the wing is still dead straight. Thank you for your suggestions. I also purchased a 1950s Fox 35 to go with it, so I'm really excited!
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Chris,
Great looking model.
Are you making a tank hatch?
I'll be silking soon.
charles
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Looking great Chris #^
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Yes, there is a tank hatch... I know there isn't one on the plans, but if there's one thing I've learned from talking to modelers over the years, it's that if you make a tank inaccessable it WILL leak.
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So true. The covering job is looking great. Now remember when you brush the dope on, do not back stroke. That is when the dope goes thru the weave. Of couse I don't worry about that as I dope one rib bay, turn wing over and dope a rib bay or two on this side. After several coats the weave will still have some spots, but with enough clear you can't see any runs under the fabric. H^^
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I had heard somewhere to use a foam brush. y1
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Either type, just don't back stroke. H^^
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I know I'm rehashing a pretty old post, but I finally got around to doing some silk on the el Diablo and thought you'd like to see the preliminary results. Obviously I have a LOT more work to do, but right now it is a start, and as amazing as it may seem, the wing is still dead straight. Thank you for your suggestions. I also purchased a 1950s Fox 35 to go with it, so I'm really excited!
An El Diablo with silk covering and a '50s Fox .35! A great, nostalgic combination. ;D
BIG Bear
RNMM/AMM
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I just wraped myself up in saran wrap and jumped in the pool.
Charles