How much time should I plan on to do a really first rate doped (silk?) finish? I've heard of people talking in terms of months.

Abu, I have painted planes with dope but I haven't applied silk and dope. My experience with dope is that it takes a little longer because many of the dopes aren't as opaque as other types of paint. You have to add several coats to get the colors as deep as they should be. Other than that dope dries very quick. You can use a retarder if it's too warm and you do want to watch the humidity because dope will "Blush" (get cloudy) if the air is too damp. Also you have nitrate and butyrate dopes. You can put butyrate over nitrate but not the other way around. Nitrate dope is often used on non-fabric parts to aid in adhesion. You can add banana oil to reduce the shrinkage of the dopes or get non-tightening dopes from Sig. Those dopes have lower shrink rates as compared to some other dopes from Randolph and other Major Mfgs. Be prepared to pay for hazard fee if you order from the larger Mfg's. And don't forget your thinner, if memory serves, you need both types for both types of dope. Just to be safe make sure to ask. I think the whole process does take longer but not THAT much longer all things considered. Hope this helps..

If you decide to do a dope finish, seriously consider using Brodak's dope. The solid colors have a lot of pigment, so coverage is excellent. Even the clear is so thick I've rarely used any thicker than a 50/50 mix with thinner. An initial color coat of silver also helps the coverage of the final color coats a lot. Using quality stuff like Brodaks will speed the process up.

Butyrate dope skins over quickly but it continues to gas off and shrink for literally years. When brushing, it is better to resist the temptation to brush over and over the same area in an effort to get it level. It'll make a mess as the skin tries to form and the brush dabs into it. For the same reason, whenever you dip into the paint to refill the brush it is better to make your new stroke going toward the last spot painted and stopping the stroke there, rather than the more natural way of touching the brush down where you last left off and continuing in the same direction.

Many years ago, at one of the international scale championships, one of the Polish entrants in control line had a beautiful P-38 with a fabulous aluminum dope finish. At the next championship two years later, he entered the same airplane. Only this time, the wood grain was showing thru the paint.

Nowadays, one might be better off using an automotive-type primer to fill the grain before the color coats (but test for compatibility first) instead of the butyrate type filler coats.

When clear-doping a silked wing or tail, often gravity pulls the wet dope thru the porous silk forming unsightly puddles and drips on the underside. All sorts of elaborate ideas have been used to counteract this. I had a very simple solution. Just hold the wing vertical instead of horizontal, i.e., stand it on its leading edge or trailing edge instead of flat on the table. You may not even need as many coats to fill the weave, either.

Also, butyrate is only hot-fuel-resistant, not really hot-fuel-proof. BTW, the term "hot fuel" does not refer to the temperature; it is a slang expression from the 1940's when most model engines were still spark-ignition and burned a gasoline-oil mix. Even before the glow plug, people were experimenting with alcohol-based fuels for racing and other maximum power uses and these were called "hot fuels". Soon, the experimenters noticed their nitrate dope paint jobs were being eaten away, especially when the fuel contained nitro-methane. Butyrate dopes stood up better and were quickly marketed as "hot-fuel-proof".

Hi!
Why use dope at all nowadays when there is Oratex (best)and solartex (next best)?
I have used both silke and dope on many airplanes years ago and the last 25 years used the new materials and there is no doubt that new material like Oratex (same company in Berlin, Germany that makes Oracover ) ought to use automotive 2-part acrylics like SIKKEN:s Autocryl for best results and the paint has to be spayed on.
Regards!
Jan K
Sweden

As far as the question of "how long?", consider that you will cover the airframe which involves priming the bare airframe with dope (I used nitrate) and then attaching the covering. After that comes a coat of nitrate to tighten the covering. Next I added a light 2nd coat of nitrate mixed with talcum powder to fill the weave of the fabric. After that it depends on what you want. Full scale gets a cote of silver primer to protect the fabric from UV. Then comes however many colors you want. When I built a Proctor DR-1 I skipped the silver coat and primed the covered airframe in light blue I masked off and sprayed the background areas for the markings and than used a brush to add the streaky green. I sprayed light coats to avoid overfilling the fabric. The sig butyrate that I used for the color coats has a good pigment content and I was very happy with the results. If you are careful not to over do it you can get a very durable and authentic looking, albeit labor intensive finish. There is an Antoinette in my local hobbie shop that over the years has had some of the lightly built parts distorted by the ongoing shrinking of the fabrick through the years.

Some years ago I did my 60 size Piper Comanche (Wing kit) in silk and dope. I counted the number of coats. Would you believe 28!! This plane had planked wings as well as fuse and tail feathers. I filled the wood with a mixture of dope and talcum powder (almost a paste) and sanded liberally until almost all of it was gone. This took 3-4 coats sanding between each. Next lay on 4-5 coats of clear thinned about 25% and lightly sand. This forms a base for the silk. Then came the silk which was applied by coating it with thinner only. I would next apply 2-3 coats of the clear/powder paste and sand being careful not to cut through to the silk. After 3-4 coats the weave of the silk disappears and you can again carefully sand using 320 WET!
This takes a couple of applications or more until when held at an angle to the light it shines and no imperfections are found. If you find anything now is the time to fix it. Then comes a coat of either silver or white. The silver will show up any more imperfections. Last chance to fill them with dope and powder. Now comes the base color. It will take 3-4 light coats and sand. Then repeat using a finer grit - like 400 WET. Next comes the masking and painting on the trim colors.

It is important at this stage to lightly sand everything with 600 WET. This will get rid of the edges left by the masking process and prepare the whole shebang for the final coats of clear. Put about 8 coats of clear - really build it up. Again sand with 600 WET, then use auto polish (I use Dupont paste), then toothpaste!!! It will look bad until you get to this final sanding polishing process.

I used AeroGloss dope and thinned it at least 50-50. Buy your thinner from the auto paint store by the gallon. You will need it not only for thinning your paints but for cleanup of your sprayer. I used an automotive touch up spray gun for the entire process. I have also used on other previous models a regular Badger sprayer with a compressor. The touch up gun works better but is costly.

How long?? Good question. I spent the better part of 3 months doing the Comanche. Way too long but it was beautiful. This was done over 15 years ago. I still have the plane. There is NO wood grain showing but the white has yellowed and the red has shifted colors - the cowl is lighter than on the rest of the plane. Oh yes, if you ding it you have a real job on your hands to make a patch look as good as the rest of the plane.

Hope this helps.

Squire,

Three months is more like the sort of time frame I had been hearing about for a really first-rate (i.e. completely scale looking) dope finish -- due to the need for a great many coats with drying and sanding time in between. BTW, did you allow any "curing time" between coats? And how soon after spraying on a coat of dope did you sand?

BTW, I have a hard time conceptualizing how I'd go about sanding a ridged surfact such as the top of a fabric wing without sanding some parts down more than others. Any tips?