stunthanger.com
Building Tips and technical articles. => Paint and finishing => Topic started by: John Rist on April 21, 2011, 08:50:35 AM
-
This will be my first Silkspan covered airplane since 1960. All of what I have done lately has been Monacoat. SO all comments welcome.
I plan to cover the whole airplane with silk span. I have on hand Brodak Butyrate Dope, Butyrate Sanding sealer, and Brodak Butyrate thinner. From what I read in this finishing section - I am guessing the following could be a way to go.
1. Dope intire wood structure with 50-50 thinner/dope.
2. Sand between coats - repeat three times for three coats.
3. Apply silk span wet. Dope in place with 60 - 40 thinner/dope
4. Several coats of Sanding Sealer 50 -50 thinner/dope.
5. Prime with ?
6. Paint with Rustoleam.
This is an electric powered airplane so hot fuel proof is not a requirement. Profile scale is viewed at 15' so I am looking for a respectiable 15' finish .
-
Sounds about right John. After the sealer coats have been sanded. Two thin coats of butyrate clear should be all you need for a primer while using the spray can stuff. Bring it to the meeting Monday, May 2. Shoud be gassed or dry by then. H^^
Hay I could bring the silkspan, dope, thinner, & paint brushes to the meeting and we could stink up the Huntsville Public Library. Could be the program - How to apply Silkspan. LL~
All kidding aside - I'm suspect that it is hard to work the wing tips, as well as some of the other sharp curves, smoothly with silkspan. Could I not seal these areas with thinned epoxy and feather the silkspan to match.
-
It is actually very easy to work sharp curves with silkspan. One nice thing about the product is small wrinkles (over wood, not open bay) disappear with a little dope and sandpaper. Also, you can overlap small pieces. After a few coats of filler and sanding, the seams will become unnoticeable.
Tip#1: If you are doing this don't make a sharp knife cut. Use sandpaper, a block and edge of your building table to cut. It feathers the edge making the seam easier to hide. Tip#2:Don't apply to sharply concave surface, or 90 degree surface (ie:wing/fuselage junction) with one piece. It will pull away and leave a blister. Use two pieces here...see tip #1. Primer...why not rustoleum primer?...or better yet, since you started with dope, finish with the same. A few coats of Brodak clear and you will have a light, shiney finish. 8)
-
An all-dope finish is far & away the easiest to repair, and lighter than Rustoleum. And since lighter flies better, it might not crash and need repairs. Since repairs almost always add weight...you see where I'm going, right? y1
-
Makea the sure the scalple blades are virgin .
Used tears the tissue .
Butrate lifts in concave corners so dont lap tissue and wing / fuse joints .
Nice aeroplane . Nice scheme . Can I havea go ? :X
-
Sounds like a good plan, basically what I do but if it was me I'd skip your #4, the sanding sealer step. I'll spare the lengthy details but I would definitely skip the Rustoleum too. I can almost guarantee the day would come when you would regret using it on this plane. I used to use a lot of various rattle can stuff in the past, including Rustoleum, but I finally "grew a pair" and switched to spraying Brodak dope a couple years ago. I wish I would have made the move many years earlier, it's waaaay better.
I'd stick with your first three steps but then after all your silkspan is on go right to more clear. After my silkspan is on the solid areas I just give things another 3 or 4 coats of 50/50 clear, sanding a bit with some worn 180 or 220 in between coats. If necessary, touch up a few little areas with that same routine if you need to until satisfied. Pay extra attention to where any loose edges on the silkspan might be a problem, bury them in clear and sand them smooth. Repeat as needed.
On the open bay areas I use Polyspan and usually end up with 7 or 8 coats of the 50/50 on it before I'm satisfied. I just spot sand any lint or dust specs and stuff like that out in between coats. Give everything a nice final sanding with 400 and your ready to start spraying your color.
The plane looks really nice so far, don't get in a hurry, this one deserves a nice dope job. y1
Did I say skip the Rustoleum?
-
but I finally "grew a pair" and switched to spraying Brodak dope a couple years ago. I wish I would have made the move many years earlier, it's waaaay better.
On the open bay areas I use Polyspan and usually end up with 7 or 8 coats of the 50/50 on it before I'm satisfied. I just spot sand any lint or dust specs and stuff like that out in between coats. Give everything a nice final sanding with 400 and your ready to start spraying your color.
Two questions - Will a detail spray gun from Harber freight work? Like the:
http://www.harborfreight.com/hvlp-detail-spray-gun-46719.html
#2 where do I get Polyspan. I take it that you can mix silkspan and polyspan on the same airframe.
-
This is the one I use John: http://www.harborfreight.com/touch-up-air-spray-gun-66871.html
I've got two of them, one for color work and one I use for clear only. They're cheap and work real well for the "Average Joe". I use mine with a 150psi Craftsman upright compressor with a pressure regulator and I added an inline water trap. I use a 25-28psi setting on the compressor and about a 50/50 dope/thinner mixture with this gun.
I also use a smaller Badger plastic model type airbrush for small areas and detail work. I have it set up to work with the same compressor and I use a 30psi setting with it.
I get my Polyspan directly from Tom Morris. There are some other places to get it from too, I don't know them all. It takes a little getting used to but I love it and won't use anything else now. It's a lot stronger than silkspan, not any heavier, and holds up much better over time. You can do a Polyspan search on the forum here and find a bunch of suggestions and tips on using it, many of them from myself.
-
Great Thanks. Control Line Central has Tom Morrris Polyspan in stock.
http://www.clcentral.com/proddetail.asp?prod=POLYT.
Is there any reason not to cover everything with POLYSPAN
#^ #^ #^ H^^
-
Good decision RE: polyspan. I still can't get it over wingtips very well so cover the main wing w/polyspan, tips with silkspan. If you have to do that, it's no big deal but polyspan will definitely outlast silkspan down the road. 8)
-
Good decision RE: polyspan. I still can't get it over wingtips very well so cover the main wing w/polyspan, tips with silkspan. If you have to do that, it's no big deal but polyspan will definitely outlast silkspan down the road. 8)
As the old saying goes the check , I mean my stuff is in the mail. Control Line Central shipped, today, a roll of polyspan and my lettering spray mask. I picked up a spray gun from Haber Freight. As suggested I will go with an all dope finish. Is their any reason I can't use Aero Gloss dope over Brodak clear. The local hobby shop still has a fair collection of Aero Gloss dope.
??? #^ H^^
-
I may be wrong in this but my understanding is that Aero Gloss is a very different product than Brodak or Sig dope and may not be compatable. With the work you have already put in I wouldn't chance it. Brodak ships PDQ and can be ordered over the phone or internet. Brodak white really sprays nice and covers well, more pigment than Sig. 8)
-
I may be wrong in this but my understanding is that Aero Gloss is a very different product than Brodak or Sig dope and may not be compatable. With the work you have already put in I wouldn't chance it. Brodak ships PDQ and can be ordered over the phone or internet. Brodak white really sprays nice and covers well, more pigment than Sig. 8)
Cool Brodak it is! 8) H^^
-
John,
Polyspan is really great stuff, but if you haven't used it before be very patient until you get the hang of it. I'm not trying to spook you, so don't be, but it is quite a bit different than using silkspan. This is mainly when the shrinking with heat step comes in. Also, make absolutely sure you have the correct side out when you go to put it on. It well be well worth your time and help you a lot to do some searching here on the forum and going over many of the suggestions for working with it. Personally I only use it over the open bay areas. No real reason other than I'm better at doing the solid areas with silkspan.
Here are a few posts to pick through where I have offered some tips for using Polyspan. I hope this helps you along...
http://stunthanger.com/smf/index.php?topic=19407.0
http://stunthanger.com/smf/index.php?topic=20217.0
http://stunthanger.com/smf/index.php?topic=19407.0
-
All good reading. Thanks for the list. I have put on a lot of heat shrink film so I think I will enjoy applying polyspan. I may well use silkspan over the solid wood areires. Will post pictures when I get going.
-
Yeah, skip the Aerogloss. It's basically non existent anymore anyway. Build your inventory and get used to using products that you can replace. y1
-
Hi John,
Their are two main reasons, IMHO, for not using polyspan on the fuselage: 1. if you are not careful while sanding, the polyspan will develop a critical, almost terminal, case of the "fuzzies". 2. It doesn't go around curves as easily as silkspan.
Polyspan on open bays, silkspan on the rest.
Big Bear