Well guys,

I have been thinking about doping my next plane. Silkspan first, of course. What do I need to d it? Do most of you that use this method use an airbrush set-up? Back in the good ol' days, (60's), I would go to the LHS an buy a couple bottles of butyrate dope and go home and brush it on. I'm sure it's done a different way now.

So what kind is a good type to start with and what tools do I need to apply it with? Everything for the last many years that I have done has been Ultrakote. I would like to try for a really good finish on my next project, I am going to try a full fuse plane.

There are probably several different types of material available now for coating the wings, and I just want to start with the basics for now, no fancy mixes, just something I can do a pretty decent job with if I take my time. The covering won't be a problem, I have even covered a wing with wet newspaper, let it dry, dope it and flew it once when I was not able to get something else real quick.

Tell me what you all are using mostly for your finishes.

Hey, RW,
How goes it? Ryan and I are going to run to Des Moines for part of a contest Sunday. Expecting a windy afternoon.

Gee, dope..Man that is a subject of great debate. But here are some things that I think will always work pretty well.

Brodak dope is the way to go unless you can get Randolph aircraft dope (same stuff, only can be bought cheaper).

Some really good camel hair brushes. Lots of fine sandpaper. Yellow-back 3M auto body sandpaper is the class of the act.

Silkspan is still really popular and easy to get . Another good option is Polyspan, a synthetic dress lining that Tom Morris sells. The only cautions are that it doesn't go around curves easily and it fuzzes up a lot if you sand into it. But incredibly strong stuff. Maybe 10x stronger thatn silkspan? Just put plenty of coats of dope on it before you try to sand it. A few guys still use silk, but it tends to be expensive. There is a place in California called Thai Silks that sells nice material and a lot cheaper than SIG, though.

Basically you sand the airframe smooth and apply 3-4 coats of dope around the edges. Lay the silkspan on a towel and wet it good with a sprayer. Lay it in place (grain span-wise), pull it snug, and use thinner or 90-10 thinner-dope brushed through the 'span to stick it down. Might need to rub it down a little to make it stick. Use fine sandpaper to trim the edges after it's dry.

Brush on a dry first coat or two to seal the tissue. Then spray or brush until happy with it. Wet sand if you want it really slick.

A lot of guys are spraying dope or auto paint with the low-price HVLP sprayers from Harbor Freight. I have one, but haven't had the weather to get it out and try it yet. But a decent quick job is to apply a dope base and finish with spray can Rustoleum from the hardware store. A pretty nice finish for not a lot of work.

But go over to Stuka Stunt and search around. There is a ton of good material over there on finishing., including dope, auto paint Rustoleum, epoxy, PolyCrylic and silkspan, Japanese tissue, etc. I just barely scratched the surface. Sure is fun when a paint finish turns out nice.

See you later,
Kelvin

Raining cats and dogs here. Another dreary weekend in the making.

I always covered my wings with what came in the kit. Did it just like you said, wet it down, dope the bare bones and lay it on, pulling it tight all around. My wings always came out good. My paint jobs were never "slick" like some of the pics I've seen, But at that time I was just trying to seal the sllkspan, and that was it.

What is Brodak dope? Butyrate, nitrate, or something else? About how much should I get, I want to have enough for a couple of jobs. Pint, quart, gallon, or barrel? Will it store okay for a while? And I will need some thinner too, right?

I don't think any of the LHS's in Lexington carry it, or maybe I never really looked.

A roll of Ultrakote is 12 bucks and will do a wing with some left over. I'll check it out at Brodak's website.

Brodak is butyrate, except they sell nitrate clear for base coats. A lot of guys use nitrate for the sealer coats on the bare wood. I've done it with nitrate and butyrate. Only difference is that the nitrate is a little stickier maybe.

I use their thinner, but Dupont 3608S thinner works good, too. I just haven't tracked down a source of the Dupont thinner yet. When I find it I'll change over. Just be sure to use the same thinner all the way through. Changing thinner in midstream may be the cause of some compatablility problems.

You can order Brodak from Brodak direct or from Len Neumann. Dope lasts almost forever as long as it is stored cool, with the cans upside down so the air can't get in. REally, turn the cans on their heads. It works.

The slick finishes are a result of lots and lots of wet sanding and buffing. I've done just enough to appreciate how much work a really fine finish is. For instance, Windy Urtnowski sprays a full quart of clear as the top coats on his planes. He says that he spends about 100 hours sanding a finish. If you want to see how the real hot shoes do a finish, get some of Windy's tapes on painting. Zowee.

I'm going to try it at least once to see what kind of job I can do. The U-Kote does really look good and my RC planes even have the fuse covered in it and they came out really good.

I have done some automotive painting (UPS Buster Brown) on the UPS road tractors for several years using DuPont IMRON and then clear-coating them. That was BEFORE OSHA stepped in with the required respirators and all. Probably why I forgot half of what I learned back then. Now I can blame it on Alzheimer's.

I'll probably give Len a call and get some stuff. My next kit will probably be a simple full fuse ship from Brodak. I'm not really ready for the top dollar stuff right yet, just need to build up my fleet with something I can put a lot of miles on. Or laps. The way we're working it will take me 6 months to build something, and I don't think my wife will let me tie up the dining room and table for that long. She didn't say much about the Twister build, but I got thru it pretty quick and enjoyed it. If I can get all the yard equipment out of the garage from winter storage, then I can work in there.

Thanks for the info. Paint brushes, huh? I have a good 2 1/2 gallon pump-up weed sprayer. Hmmmmm.....

Or blame it on years of not wearing a respirator

Sorry, couldn't resist

Phil

RW,

Brodak dope is made to specific Brodak formulae by Randolph's. They have extra solids in the dope, and the thinner is a fairly quick drying formula. If it is humid, you may need to also use some retarder to prevent blushing. Blushing is moist air bubbles trapped within the paint because it dried too fast to let them escape.
To get the finish you describe, you will need to use several coats of dope and sealer to completely prepare the surface before covering. That is important. Covering mistakes is a hard, sometimes impossible task. Lots of filler, lots of sanding, BEFORE applying the covering. Knock the sharp edges off the ribs and edges around the open spaces so it won't sand through easily. When it is just the way you want it, apply a final coat of clear, then cover.
As mentioned previously, apply silkspan wet, and use thinner to hold it down. Wetting the silkspan causes it to expand so that it pulls out all extra wrinkles and blemishes when it dries. It will shrink more if rewet.
Keep the brush wet with dope as you paint or the bristles will come out and you will have a camel hair covering. Apply extra coats of dope around the wing ribs and edges next to open spaces as these will sand through easier. When you have sanded until it is glass smooth, sand it a bit more. When you are really finished, give it another sealing coat of very thin clear, with no sanding after. Now you are ready for color. We can talk about that more later.
I would stick with Brodak all the way. One exception is that I use regular lacquer thinner to clean brushes before using Brodak thinner to clean them (yes, twice) because the lacquer thinner will get most out and it's cheaper. Mixing products can get you into compatibility problems. Even things like different drying rates can cause a layer to lift off.
Let the dope dry thoroughly between coats. The same goes if you use some other product such as SIG. Whatever you start with, use only that product. You can mix and match later.
If you decide to go for a "decent" finish instead of a "super duper" finish, the instructions are on the Brodak can.

George

Geprge and kd,

Thanks for the info. I am going to just try for a decent finish on the first one to get comfortable with applying the dope and covering. What is a good ratio for dope/thinner, about 50/50 ? Or does it differ for the wood and then the silkspan?

Is it best to also cover the fuselage and use the same method of painting as the wings? This should give a good smooth blended effect to the entire plane. I've heard that trying to keep the grain from showing takes a lot of coats and still may not do it.

Thanks for the advice.

RW,

First question is hard to answer. Small jars are usually ready to apply. Larger quantities are usually thicker. For brushing, 50-50 is usually good. For spraying, you need more thinner. How much depends on your equipment. I prefer brushing for a "decent" finish. Spraying is a lot faster though.

First you must sand the plane VERY well. Put on three coats, sanding between coats. You will get raised grain so you must sand well. Assuming all is well (smooth and level) apply one more coat without sanding.

Now you apply silkspan. I apply mine wet. Make sure you run the grain spanwise on the wings. Many people apply silkspan over all balsa surfaces. This gives a smoother finish with less effort.

I use thinner to apply the silkspan so it will adhere from the bottom by softening the last coat of dope you applied. When it is dry you can apply enough coats of dope to seal the silkspan. Sand between coats after the second coat. Be sure to sand only to the silkspan, don't sand through it, especially at wing ribs. If you do sand through, a thin coat of Brodak Rejuvenator can sometimes rescue the rip.

Next apply several coats of sanding sealer to fill the silkspan, sanding well between coats. Apply one more coat of clear, then a blocking coat of gray. The blocking coat prevents your seeing brush marks through the wing panels when the sun shines through it. It also allows you to use fewer coats of color.
When you apply color, start with the lightest colors, then do darker ones. Some people apply the lighter color over the entire plane, then apply the next color, etc. A lighter way is to mask off all that is not going to have the lighter color, then mask for the next color, etc. (Mask whatever you're not painting).

Make sure the dope is thoroughly dry before applying the next coat. This is especially important when applying color.

When brushing, make sure the brush stays "wet" otherwise the dope drags off the brush into the dope. Keep the brush moving fast and don't brush over the same area too long, otherwise ... hairs.

Of course this is only one way of doing it, there are infinite other ways.

I'm sure others will supply alternatives that work for them. Choose whatever fits your needs.

Good luck,
George

I use Brodak dope to attach Sig Koverall, then I will be painting with latex house paint. To keep latex house paint fuel proof you have to put a clear coat. I personally don't like silkspan since it's not as durable as I would like. I have dropped screw drivers on the koverall without any holes. The Sig koverall is on the heavy side...

Model airplane news has a good on line article on how to paint with latex house paint, a nice way to go. Much less expensive and you can get any custom color mixed at your local home depot or Lowes.

Good luck!

That is interesting, latex house paint. I think I had read some other threads somewhere about it, but I'm not sure.

I finished a TWISTER a couple months ago and used RUSTOLEUM on it. On the balsa I first used R-OLEUM wood primer and sanded each coat almost back to the wood to fill the grain. It still left some of the grain showing when I painted the wood parts, the wing I covered in ULTRAKOTE, since I had several rolls laying around. The R-OLEUM bright yellow and the U-KOTE bright yellow are almost a perfect match, and since this was just for "training" purposes, I wasn't too worried about the final outcome. But I think it looks okay for it's purpose, it won't win any beauty contests.

My next project I am going to try doping, as I plan on a full fuse plane and a little more attention to detail. And a better paint or covering job. Here is my TWISTER results, haven't flown it yet.

As things stand, the weather is supposed to be great for Sunday, and I am going to fly. We haven't had a break around here for months, weather-wize, so if nothing happens, I'll get to fly this weekend.

Hey, RW, that looks fine! Next time, cover the fuselage with silkspan before assembling the wing and fuse. You can also cover the wing and get it filled before assembly if you paint it. Then the grain issue mostly goes away. Not entirely, but mostly. I think you can get away with less paint, especially filler, too, saving weight.

I really like SIG Koverall, too. But it is pretty heavy for a stunt or sport CL. Scale builders maybe can tolerate higher weight than stunt.

The latex idea is so attractive, but a fuel proof clear is not a fool proof thing. For clscale-what works well as a top coat? Urethane, dope, auto clear?

We have several things coming together to fly this weekend, too. The weather is promising....

Oh yeah,

Forgot to mention that the flaps are U-KOTE covered but all else is painted.

What I want to try for on my next plane is a good smooth transition from the wing into the fuselage. It's called a fillet, but how is it done? When I epoxied my wing into my fuselage on my TWISTER I used a large syringe and filled it with epoxy and sorta used it like a caulking gun. Maybe this isn't the way it's supposed to be done, but my wing is solid as a rock in the fuse. I did coat the balsa sheeting all around before I slid the wing in the last inch so the epoxy is on the mating surfaces inside the profile fuse to the wing.

I have seen pictures of other planes and some of them are really blended in well where fuse meets wing. How do they do it? Is it like wood filler that is used and then a finger tip or something run along it to give it a concave shape and sanded?

One thread somewhere mentioned making the fillets and gluing them on. So I am curious as to how to get a good transition from wing to fuse. What is the procedure most guys use?

In list form:
Epoxo-lite from SIG. Used by many flyers for years. Two part, dark brown. Kind of gloppy and heavy by my lights. I find it hard to sand. Dope lifts off it kind of easily, bubbling the finish.
Aero-poxy Lite, out of the homebuilt airplane business. Two part. Pretty easy to use. Sands well. Available from Windy Urtnowski or Brodak or Aircraft Spruce. My favorite.
Balsa triangle stock. Soaked and wrapped. Glue and sand. Lightest. Not hard to do with a little practice.
Leather. Bill Sawyer sells this material in a variety of sizes. From the pattern making industry. Cheap, light, easy to sand. Glue it down with Ambroid glue.
Home brew epoxy-mix 30 minute epoxy and microballoons to a think paste. Smooth on with a round tool. A little harder to sand and probably a little heavy.

Just a note-in general it's better to fill the wing-fuse gap with as much balsa as possible. Glue is heavy. Little chips and shims as needed. Not all kit parts fit all that well. And if the wing construction is off a little. There are some good links to info about these subjects. I'll see what I can find for you.

Aha, here's a good one:
http://www.clstunt.com/htdocs/dcforu...ID1/13537.html

BTW, I had not seen the Brodak how-to brochure on painting with dope. Get one.

And here's the source for the leather filltes:
http://www.clstunt.com/htdocs/dcforu...mID2/9347.html

Wing/fuselage gaps: I have a balsa stripper that will make strips as small as 1/32 x1/16. These strips can be used to shim gaps in joints anywhere on the model and produce a stronger, lighter, and less messy result than fillers. If you use soft balsa stock, it will easily sand flush without marring the adjoining wing and fuselage surfaces. Also, for very small gaps, you can use Elmer's Wood filler, quickly wiping off the excess with a water-saturated cloth. When it dries, lightly sand it with 400 grit paper and carefully seal it with a bead of thin CA.

All the bases seem to have been covered here, but for what its worth, heres how I've been doing it since the mid 50's.. Mix a thin paste of flour and water, cut the tissue to approx. size, smear the paste onto the edges of the surface to be tissued, apply the tissue working from the centre out to the ends to get it as tight as you can and allow the paste to dry. When the structure is covered and the paste dried, trim the edges and stick 'em down, then mist spray the tissue with water, this will shrink the tissue. When dried, take it outdoors and apply 2 coats of thinned dope to seal the tissue. Maybe a VERY light sand before painting. My Dad taught me how to tissue cover model planes, he was born in 1914 and an aeromodeller all his life.........John