I have a GP Super Sportster 60 under construction. Beginning to think ahead to covering. Considering using a fabric covering.
Seal the Koverall with 1 - 2 coats of Sig Nitrate Clear Dope and then apply the finish of your choice.
My questions are: Does the Dope seal and fuel proof the covering ? Will the Dope prevent the paint from soaking into the fabric ? Can the Dope be used to fuel proof the firewall and engine compartment ? Where the Dope, Fabric, and Balsa all make contact does the Dope permenantly attach the fabric to the Balsa, I guess what I mean is, is the Dope an adhesive ?
Nitrate dope will seal but not fuelproof. Butyrate dope will do both, but then you might have problems using any other finish over it.
Nitrate dope is used as a sealer because of its light weight. Whether or not it prevents other paints from soaking in depends on your choice of paint. Other lacquers may tend to combine with the dope. Enamels won't.
No, use thinned epoxy for that.
Yes it is. One technique is to coat the framework with unthinned nitrate dope, and then just use lacquer thinner or thinned dope to fasten the fabric.
On 1/20/2004 11:09 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
What DR1 Driver and James D. Jones said is quite correct about applying the Sig Coverall. I would like to know why you want to do it that way though (the "old fashioned" way) ?
SolarTex (considerably lighter and easier to work with than Coverite
21st Century fabric) is a pre colored, light weight fabric. The finish is fuel proof. It does not require any additional adhesive to attach to the airframe. The only suggestion I would make with this covering, is to seal the weave with clear polyurethane after all your trim is applied. This is to prevent dirt and grime from getting into the weave.
The MinWax PolyCrylic is a water based poly. Use some "FloTrol" in the poly and a foam brush. You will have a nice sealed finished with no brush marks.
Not sure about Koverall, but a similar fabric, Super Coverite, has a few suggestions. First off, nitrate dope is not fuel proof; butyrate dote is.
However, butyrate will NOT adhere well to the fabric -- something about the fabric manufacturing process. You can then apply the butyrate over the nitrate. This is the way to go for a true scale finish such as using Randolph's Aircraft Finishes.
On the other hand, after the nitrate, I would imagine you could use any other finish you choose. Most guys use thinned (with alcohol) 5-min epoxy to fuelproof the engine compartment,
On 1/21/2004 10:44 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
If you decide to go with the SolarTex, you can paint your trim scheme right on the Solartex. I USUALLY use a latex paint for painting (both trim and complete planes). Since I clear coat the SolarTex, there is no problem using latex, plus a quart (color matched) is only about $10 and that will provide enough paint for several 60+ size models.
I am the same way Chuck, I just enjoy the fabric covering experience. Most of the planes I build for myself, last for years and I never could get film to last the "distance" without repair. Just my opinion rick markel
I am just covering my new model with Koverall, it is an interesting experience and fairly easy, I have only ever used film before and not many times with that!! The koverall is great over compound curves. I doped the frame (twice with thinned dope, sand between) and put "balsaloc" around the edges of the wing and ironed down to that, that is as far as I have got except to add a little more balsaloc to overlap areas ready to do the top surface. When I dope over the fabric it should stick to the rest of the wing and capstrips. The koverall shrinks very well with the heat gun, the tail feathers and control surfaces look great, biggest problem is with frayed bits . I think I will do the fuze, which is sheeted, with tissue and dope as this will save me filling the weave to make it look like the full size metal sheeting.
and fairly easy, I have only ever used film before and not many times with that!! The koverall is great over compound curves.
around the edges of the wing and ironed down to that, that is as far as I have got except to add a little more balsaloc to overlap areas ready to do the top surface. When I dope over the fabric it should stick to the rest of the wing and capstrips. Ian
Ian, use a covering iron to "iron" down the edges of the Koverall. I put the fabric on and brush on the dope around the edges to adhere it as usual, then brush on a bit more to the fabric that`s overhanging (just enough to cover it to were you want to trim it off at) let it dry and trim it down to were it needs to be. Then "iron" it down, it will stick to the dope you brushed on the framework before you started to cover. Even if the dope curls the covering back a bit, it will easily iron down. Works great and is easy to trim because the dope makes the fabric very easy to cut. Give it a try.
My son uses the real thing: real aircraft fabric, 1.7 oz. made for ultralights. Far cheaper than Moneycote or the hobby-shop fabrics, and much, much stronger. He uses contact cement to apply it, except on foam, and plain old weldbond on the foam, though it doesn't hold as well. You could use the latex "odor-free" contact cement there. When I have some, the Stits Poly-Tak glue is great, though it can't be used on foam either. Fabrics and glues can be bought at aircraft suppliers online. Try or Aircraft Spruce and Specialty have a website that I don't have the address for at the moment. You can also buy small screws, nuts and bolts and so on for much less money than hobby-shop stuff. And it's even aircraft-certified. To cover difficult corners like the wingtips and so on you can cut from the fabric (or buy already made, but not cheap) fabric tapes at a 45 degree angle. That is, the weave runs across the strip at 45 degrees, and enables the material to conform to compound curves. The same principle works for fiberglass cloth. Edge fraying can be controlled using pinking shears instead of straight scissors. The zigzag edge prevents long threads peeling off. Steal those shears from your wife's sewing box. Don't get caught. They're not cheap, and they don't look good with glue all over them. Latex paint can be used to seal the fabric and wet-sanded (with water, not solvents) to get a super-smooth finish over which a high-gloss enamel can be applied. Be careful sanding over hard points like ribs, or the sandpaper will cut through the fabric in short order. Use 220 grit waterproof paper. Get that at the hardware store or auto parts place. The job will be a bit heavier than films, especially if you get carried away with the paint, but it won't be getting poked full of holes all the time or torn off when deadsticked into the stubble. And those repairs don't make a pretty airplane, do they?
Sometimes the "old fashioned" way is really better. But that's much like arguing kits vs ARFs. I have used SolarTex on a 1/4 Scale Baby Ace. But, to keep the finish clean, it really should be topcoated with polyurethane. When you are done, your plane will be quite a bit heavier than if you had used Sig Koverall. So, Sig Koverall is still my favorite fabric. If you are going to spray paint the final finish anyway, why not just start with the bare fabric? Sealing it isn't much more work, and you can get exactly the color you want.