If you do a Google search on Silkspan and dope covering methods, a lot of good written instructions can be found. In fact, I suggest you read one or two of them if you have never done a Silkspan and dope covering job before, or if it has been a while and you want a refresher course, or if you have tried and never been able to get an acceptable result. There is no special skill required to obtain a really nice looking Silkspan and dope finish, there are a couple "gotcha" scenarios that can ruin an otherwise simple process. I believe the two worst mistakes you can make are painting dope in air that is too humid, and using a thinner that is not entirely compatible with the dope (nitrate or butyrate).
I decided it might be a good idea to make a video of how I have been successfully achieving decent Silkspan and dope finishes for lo these 40 or more years. My finishes have never won any prizes, but the tissue (Silkspan) has always been nice and taught and the brushed dope has gone on evenly, with nice, sharp trim lines.
The subject of this tutorial / demonstration is a Sopwith Camel biplane from a Manzano Laser Works kit. My Camel first flew as a 3-channel radio controlled model, and was covered with Monokote. It experienced an unplanned encounter with terra firma and broke off half of the top left wing. Since I had originally planned to build it for control line, I decided to take the opportunity to strip off the Monokote (olive drab - the dark colored stains on the balsa are residual adhesive tint) and re-cover with Silkspan and dope. I never liked the idea of using plastic covering on a WWI biplane, so this time it will look a little more authentic. Snoopy will still be the pilot, though.
Prior to recording these videos, the Camel had been completely finish sanded and a coat of 50/50 nitrate dope had been brushed onto the balsa framework to facilitate the Silkspan attachment later.
Because YouTube limits video durations to 10 minutes, it is necessary to break the tutorial into multiple parts.
Part 1 is mostly an introduction to the concept of tissue covered models and the two types of dope - nitrate and butyrate. It also covers tools needed (sharp razor blade, paint brushes, tack cloth, etc.), and the topic of covering compound curves.
Part 2 is A discussion about the logistics of partitioning the covering pieces to best accommodate the airframe is given, along with preferred grain orientation. It covers where to apply the base coat of dope to the wood framework, and where not to apply it. A demonstration is given of how to seal the loose edges of the newly applied and dried Silkspan
Part 3 introduces safety concepts, and discusses the compatibility issues of nitrate and butyrate dopes, along with demonstrating how to identify the Silkspan's grain and shiny vs. non-shiny side, if applicable. Wetting and applying the Silkspan to one of the wingtips is also shown.
Part 4 shows how to trim the overhang from the newly applied Silkspan. A demonstration is then given on how to properly cover the wingtip's compound curves. Supermodel Melanie, who has been graciously operating the camera, makes a cameo appearance. In case you were wondering (you probably weren't), I kept looking down toward the end of the movie because our cat wandered into the room and began rubbing against the camera tripod, and I was making sure she couldn't tip it over.
Thanks for watching.
While preparing for Part 5, I came across a couple items that should be included in this tutorial.
The first is a method for trimming pieces of Silkspan that are too small to grasp with your fingers while cutting with the X-acto blade. Being wet makes it even more challenging. I use a pair of tweezers that has flat tips about 1/4" wide to grab the Silkspan. Those same tweezers work great when applying the wet Silkspan and a small section folds over onto itself and is difficult to unstick. They are also good for grabbing an edge of wet tissue to pull it tight across an open span like across wing ribs.
The second is a method for achieving a constant width trimmed edge for creating an overlap area. I use a popsicle stick, which is about about 3/32" thick, to sit on the edge of the framework, and then run the X-acto blade along the top of it. Keep shifting the popsicle stick as needed until you have trimmed the entire edge. If you need a larger overlap, use tape two together or use a piece of hard balsa.
Part 6 of the video series shows the masking and preparation for painting. Her are a couple photos of the progress.
Nose area masked off to keep olive drab green out of red area.
Roundels masking tape still in place. Stripe masks removed. Those areas will have a white base, with red and blue trim.
just earned an honored spot in my great hobby shops list. Back in April, I placed an order for a bunch of Brodak dope for use on my Sopwith Camel. They were chose because of having the best price I could find. After finally getting around to using the dope, I notice the Cessna White was missing, so I wrote asking them to see if it was ever shipped. Their records confirmed it had not been included in the order, so they are sending it now. That is the kind of honesty that deserves recognition!
Here is a short write-up on buying dope by the gallon to save money.
March 2013 Update
I finally completed the wing repair and totally refinished the entire Camel. About a pint of acetone and lots of paper towels were used to wipe the color coat of dope off the entire airframe. Then, a couple coats of clear were applied, and a couple coats of white base color. Sanding was done every other coat. Even with the white base, it took five coats of yellow to get a good opaque color. Just two coats of olive drab green were needed, and three coats of Insignia red. Prior to painting, two additional coats of white were applied in all the areas where white would be needed in order to avoid having to brush many coats of white over color. When the weather warms up, I plan to spray a light coat of clear over everything.
Melanie with the Manzano Laser Works Sopwith Camel - Set up for electric-powered control line.