Nitrate/Rustoleum

I see some guy's using Nitrate paint with a month long cure, then spraying Butyrate over top. Mixed results.

I don't see any reasoning to wait more than 24 hrs when spraying butyrate over nitrate. I wait about 20 min then begin my second coat. In fact I can actually see that not toothing into the underlying coat properly if you wait too long. Dope is time consuming as the coats actually melt down the coat before it. The building process takes longer as each coat has to dry. I just wait about 2-3 weeks on my clear coats if I'm going for the rubbed finish. I found Sig dope to be the best for a rubbed finish as it shines better than other dopes I've used. I also found it to wet sand easier without loading the paper. My suggestion to wait when spraying Rustoleum is due to one being laquer and the other enamel. A enamel top coat would certainly prevent the underlying laquer solvents to gas off properly.Ken

The only time I've used dope is brushed nitrate on tissue covered peanut scale models. Can I get a decent finish on a sport plane with a brush?

Jim, I've had some real success with using a brush and dope for a finish. It all boils down to the proper brush and the way the dope is thinned allowing it to flow. After all, most of your older magazines that show stunters from the 60's were all brushed. The problem lies with the dope. Back then the dope had in my opinion better characteristics to it allowing it to flow and also to shine better and have better fuel proofing capability. Nowadays, you must put a clear coat on top of a dope finish not only for appearance but for fuel proofing. To answer your question, yes you can get a decent and beautiful finish using dope with a brush. The problem is you can't brush on a clear coat as it will soften the underlying colors and you will drag it all over the plane. The finish clear must be sprayed.

My suggestion to use dope was to keep the compatibility the same as you suggested nitrate for the base. Yes, nitrate can be used as a base for enamels so Rustoleum should work assuming everything is left to dry adequately. Allen Brickhaus uses the Minwax Polycrilic method which is a water base polyurethane for a base, he then sprays Rustoleum over that. This seems to be the norm and the water based poly dries within 20 min. I know he also mixes a tad of the lightweight spackle that isn't drywall compound but the small little tubs that you find at a hardware store. He mixes some into the poly making a slurry which makes an extremely smooth finish which sands very easy. Another coat of Polycrilic and the Rustoleum goes on. I've never done this but I've seen it and it produces a very nice finish. Here is some info from Flying Models although your using auto top coats, the same theory is applicable to Rustoleum and I do believe Allan was using the same primer prior to top coating http://flystunt.com/ARTICLES/FMFINISHINGARTICLE.htm Ken

Nice article.


I had heard about the Minwax Polycryllic silk covering trick a few years back and decided to give it a try with this foam Phase 3 EDF wing I put together. Thin Habotai silk and Minwax poly low gloss. I covered the whole structure including adding fillets to the already covered rudders, although it doesn't show very well because the silk is a really tight weave and very thin. I would recommend a warmer environment for application as this was done in a very cold shop and I had a few wrinkles pull into the silk as the Poly dried. I draped a full covering sheet over the entire top 1/2 of the model with cutouts for the rudder and then brushed the poly on. Since it was a electric, no nitro proofing was needed so I shot it with a available white acrylic paint once it dried.

The article Ken posted then goes on to talk about nitro proofing the covering.

As mentioned, Nitrate has good adhesive properties so it is used extensively for applying covering and as base coats. It gases off fast so there is not a long waiting time. Butyrate is great for painting over nitrate. If using a brush (as I do) make sure you keep the brush well loaded (lots of paint) and don't keep brushing over the same spot. If you do, the drying dope will pull the hairs out of the brush and you must remove them (don't ask). Butyrate will keep shrinking for awhile. Some flyers leave the final sanding and polishing until the dope is thoroughly dry...weeks later.

The reason you can not put nitrate over butyrate is that the butyrate takes a loooong time to gas off (weeks and weeks). If you put nitrate over it before it has gassed off, the nitrate cures and the gas from the butyrate gets trapped and will separate the layers... you can pull the nitrate off in pieces.

I have no idea what keeps the automotive finishes on...or perhaps they wait awhile before applying it over butyrate.

If you use two part automotive finishes like Imron, be VERY careful and use an extrememly fine filter mask. The forced air type is preferred. I think everyone who uses this stuff sprays it, I never heard of brushing it.

Oh on brushing...I have found that the cheap foam brushes work well. I am currently using one for initial clear butyrate and I brush on a coat, next day another coat, and do not clean the brush between coats. It softens when I dip it in the jar. I got this idea from someone else. Previously I would clean the foam in cheap thinner after each session. First problem was that the foam came off the stick. Had to glue it on with white glue so the thinner would not easily affect it.

Hope this stuff helps someone.

George