I have a sig 4 * 60 I am starting to build and I want to cover it with Polyester material I got at Wal-Mart. What is the best thing to seal this material with. I plan on using Sig Stick-it to attach the material, than use a heat gun to shrink it. I believe this material needs to be sealed before I paint it with latex paint. I want to paint it like a ME-109

Thanks

Butyrate dope is your best bet as it's compatible with any finish you wish to put over it.

John

Isn't nitrate dope the one that is universally compatible?

Thanks Guy's. I'll check with sig. I know they make both types of dope and I'll need it in a spray if I can get it. I do not want to brush it on. Because I plan on using a Latex paint to finish the project I was hoping something else would work. Somewhere I heard about a hair spray you could use and I was wondering if someone might know if it is possible to use hair spray to seal the fabric.

Thanks

ARGH!!! Jim is correct! Nitrate is the dope which is compatible with everything. Butyrate is fuel proof, but Nitrate is the one you want to seal the fabric.

John

Either nitrate or butyrate will be satisfactory to seal the fabric with. Its better to brush the seal coats in order to work the dope into the fibers. If the first coat is sprayed it will tend to lay on the surface and not penetrate the fibers well. If butyrate is used for the seal coats don't use nitrate over it as it is not compatible. If the first coats are nitrate, butyrate will go over it OK. You can use most finishes over butyrate. If you use latex for the finish coats you are just adding weight compared to using aircraft dope. If you have facilities for spraying dope, it doesn't make much sense to use a latex for finish.

I'm curious as to why you would use a fabric of unknown properties when for just a few dollars more, you could use Sig Koverall and know exactly how it will perform.

I would also recommend using a full scale fabric cement such as "Fab Tac" rather than Stix-it. I've used Stix-it and it works, but the edges tend to fray and it's hard to trim the fabric. The fabric cement has the right amount of tac making good seams easy and it holds the strands together so that it trims without fraying.

Polyester dress lining material is exactly what Sig Koverall is. The properties are well known.

There is a site, for which I have lost the link, which shows which paints are compatible over or under other paints. I'll post the link as soon as I find it again. Everything is compatible with Nitrate, but you have to be careful what you put over Butyrate and Butyrate is known to blister many finishes over time.

Where do you pick up Fab Tac?

John

Use dope for the whole job start to finish. A coat of nitrate, and the rest butyrate. Latex paint = heavy.

Fab Tac is available from Aircraft Spruce & Speciality Co. in pint cans. Dope is also available from them in a large selection of colors.

I concur with Pete913. Paint your house with latex, use aircraft dope for model airplanes.

I decided to use Polyester material because of an article I read. Here is the link. http://www.modelairplanenews.com/how_to/latex1.asp I think you will find it very interesting. I just wanted to know if there was another way to seal the Polyester before I painted it. Another RC Universe name Mr Pipercub says he seals his polyester material with Aqanet #3 hair spray. I have never used this so I was hoping to find out here if anyone else has tried this. It looks like I will still use nitrate dope to seal the fabric.

Thanks

Hair spray...It's shellac for your head.

Shellac is a bodily excretion from the asian lac beetle. [:'(]

Shellac is fairly brittle and probably will crack over time. It probably won't fill in the grain of the fabric since it's so lite. It's not film forming either.

In addition, it's water soluble and becomes sticky when wet. It's ok as a fixant on drawings or as a lite sanding sealer. Personally, I'd use real shellac for a sealer, not hair spray.

You should seal the fabric with nitrate dope. It's light weight, flexible, and will fill in the grain of the fabric.

Using dope over polyester material has some issues that you might want to know about before going to all of the trouble to use this combination.

Take a look at this site

www.stits.com

I'm familiar with the stits site, but can't find much information on dope on poly. Could you provide a summary of the issues or a more direct link.

Thanks,
Erik

Never mind, I found it.

As far as it cracking, I've never experienced it. Thats probably because I apply 2 coats nitrate with a brush. I thin the nitrate 50/50 and add 2/3 drops castor oil per ounce. I know, old school.

I might add that I never use modelling dope. I only use Randolph aviation products because they are fresher, cheaper, and the pigments are opaque requiring less coats.

Thanks

The thing I liked about the Stits system is that it is all polyester based. Dissimilar materials tend to have issues, especially as they age. If your using full scale products your probably a lot better off than buying the stuff sold at the LHS.

I know there a a lot of guys that have never heard of Stits and the airplanes I have seen that have been finished with it look really good and hold up really well.

I went to Wal Mart today and carried a piece of Sig Koverall. I gave it to the clerk and asked if they had material like that. She said no, then I asked if there was something similar. Together we found some white polyester lining material that is presumably the material mentioned in this post. I bought a couple of yards (at $2.43/yd) to experiment with. It is a little lighter in weight than Koverall. It has about the same thread size but is a lower thread count. Koverall has a noticeably tighter weave. The more open weave of the Wal Mart material will require more dope to fill in the spaces between threads, and the lower thread count is obviously less strong.

I have glued up some frames and plan on making some test panels to compare the two materials. The Wal Mart stuff may indeed prove to be a practical covering material (especially for smaller models), but it is NOT the same as Koverall.

It still makes little sense to spend several hundred dollars and weeks of work building an airplane then use a questionable material to save less than ten dollars.

Lou,
Go to a real fabric store. They should be able to show you an exact match for Koverall. The store closest to me was able to do this. Also, the price per yard is more reasonable than Wally World. I can get dress lining material for $1.75/yard.


John

I went to Wal Mart because that was the original question in this thread. I’m not adverse to trying new things. In the old days (50’s) we used whatever nylon we could find. I remember one model arrived at the field with a black fuselage and roses all over the wings. However I’ve just finished the structure for a Hog Bipe, and saving a few dollars by experimenting with a look alike dress fabric just isn’t worth the risk. I’ve been fooled before by stuff that looked good, but didn’t work as well. When you look at potential savings of maybe $10 on a project that costs about $400, it doesn’t make much sense.

There's no risk using dress lining material. This is what Sig Koverall is. You don't think Sig has a contract with a textile mill to make Koverall do you? I understand your concern with an expensive project vs. $10.00, but there really is no risk. Or, if you're still concerned, do a test panel of a broken wing, etc. to see how the material behaves.

John

Thanks everyone for helping me with this. I am going to test a peace of this material I got from Wal-Mart on a test panel and use nitrate dope. If it does not meet the desired results I will but some Koveral. The material I got from Wal-mart is a 100% polyester material and seems to be a lot like Koveral. I will let you all know how my test panel comes out.

Thanks

I have used a polyester dress linning material on a plane and used nitrate dope to apply the fabric and then brushed on "Deft" to seal it. You can buy "Deft" in a spray can at walmart too.

Jim

Thanks for the reply. What is deft? Is it in the paint dept? How does it hold up to being painted over? I plan to spray on latex paint and sell it with a flat spray lacquer.

Deft is a laquer furniture finish. Comes in gloss and semigloss. Yes, you will find it in the paint department of Walmart or Home Depot. It is not so cheap though espicially the spray. I paint or nitrate dope over it just fine. I have used the $1 a can spray paint at Walmart over it too. Not fuel proof but I just build electrics.

If it is a furniture finish like a lacquer or polyerathane is it itself full proof? I can us nitrate dope to sell the polyester than use latex paint on the plane and follow up with a cote of deft satin finish to use as a full proof finish for the paint. Do you think this would work? I am looking for a fuel proof finish to cover the latex paint I plan to use.

Deft used on furnuture is not even waterproof. A clear spray enamel over all may fuel proof it. I do not know I have not had a fuel plane since 1983