Evolution of a Paint SchemeI received many questions about CF-CLR's paint scheme at Oshkosh and pretty much everywhere I've been with the aircraft. So I thought I'd put together a post on how it came to be.
My philosophy for the restoration was to remain within the spirit of original. This translates into variances from original that improve safety, airworthiness, durability but do not significantly alter the original basic configuration or appearance.
I was lucky enough to benefit from the experience of others, primarily at Oshkosh, and with that chose Ranthane, one of only two urethanes that are approved for use on Polyfibre. There are advantages and disadvantages of using urethane but for me the advantages win out (disregarding the degree of difficulty!!) Note that trying to remain original here means using dope. Significant damage to CF-CLR resulted from ongoing shrinkage of dope over the years, so selection of better options (like polyester instead of linen) while strictly not authentic, is just sensible.
On the question of scheme authenticity. I researched all information, and looked at every image I could find, on the internet and on paper, and picked the collective brain power on the Taylorcraft Forum. It all pointed in one direction... while there were some general themes repeated by the factory in the 1930s &40's there was also a high degree of customization at the discretion of both customers, and painters.
One scuttlebutt is that painters were given full freedom on schemes as long as it was the same on both sides of the aircraft!
Although photos from 1946 are relatively rare, looking through the Alliance Photo Collection at https://www.alliancememory.org/digital/collection/taylor/search you can see even in black and white, that there were many many different schemes applied at the factory.
Another source of information is ad copy from the era. These are also mostly monochrome or two colour but provide clues. Not photos, but artist renderings that provide more ideas. This ad from February 1946 depicts the scheme I always liked.
Anthony (NC43501) also on the Taylorcraft Forum, was kind enough to help refine the scheme by creating the digital image below. I printed this and hung it on the wall in the hangar and paint booth and referenced it while pulling tapes. I made small changes to avoid problem areas i.e. avoiding door handles, cowl latches, rivet and screw heads etc. as much as possible.
When I stripped the paint from the doors and boot cowl I found some original colours, namely white and light blue. Light blue was not to my taste but the shade of white I tried to match to a Randolph standard colour and the closest seemed to be Randolph White. I wanted to keep things simple (no custom colours) so I picked from the Randolph "Traditional Aircraft Colors." I decided on Boston Maroon and Pontiac Red for the accent (I've seen other aircraft with a maroon-red scheme and I've always found the more subtle contrast very pleasing).
The gory details of preparing for and applying Ranthane are all below and I will once again acknowledge Polyfiber Customer Support. I'll also say that it's important for them to have good support because the information in the Polyfiber manual and on the website is mostly inadequate and in some cases simply incorrect. I understand there is an update to the manual in the works so hopefully this situation will improve.
Having said that I agree with Polyfiber, and there are many examples to prove, that "amateur" builders/restorers can obtain good results.
I hope the information below is helpful in reducing the degree of trial and error involved, but practice is a must!
March2018Just when you think you've got a handle on painting.......
At first glance this looks like contamination of some kind and given the problems I encountered early on, I kind of assumed the problem had returned.
So more time was spent cleaning everything, then I replaced all my filters, then I bought a new filter for my compressed air supply, then I tried a different compressor and air hose altogether and nothing changed.
This is a view through a jeweler's loop. What looked like bits in the finish was actually tiny eruptions in the paint.
I contacted Polyfiber and we concluded my catalyst was most likely the culprit. The "fine print" on the cans provides the date of manufacture and I'd never noticed it.
My slow progress plus the fact the catalyst was already nearly 18 months old when I bought it from Aircraft Spruce meant that the two year recommended shelf life was well exceeded. It still appeared fine, crystal clear in an unopened can but... Lesson learned, and an expensive one for sure.
The paint itself apparently lasts a long time but the catalyst is susceptible to absorbing moisture and otherwise going off. Moral of the story is buy catalyst as you need it, don't bother trying to save on shipping as I did and end up having to dispose of >$200 worth, and check dates before you buy!
Anyway just the right wing and a few small parts left to paint so hopefully now back on track.
Thanks again to Hualdo at the Polyfiber tech department.
November 2016I've had difficult time with topcoat application, most of it my own fault and inexperience with Ranthane preparation and application techniques.
In the winter months I was able to keep the booth at a reasonable temperature, when the hangar was too cold to work in. Things like planing and sanding the spars and other wood parts, cutting and trimming sheet metal parts and chromoly parts, resulted in dust getting trapped in every nook and cranny, apparently laying in waiting for topcoat spraying, at which point it migrated to the finish despite my diligent attempts at cleaning.
So I've learned a lot in the last couple of months and although not perfect by any means, I now have my setup working acceptably. Some of the lessons learned:
- Products sold as "lint-free" are not always free of particles that can mess up an otherwise good finish. Test everything in the booth using a spotlight. See below.
- To get to the bottom of my particulate contamination problems, I put a spotlight in the spray booth and turned out all other lights. Using an air nozzle, blow across anything and everything in the booth and position the light such that the particulate is visible in the beam. Lint-free painters rags, masking paper, paint coveralls, breathing equipment, lights, walls, everything can be tested in this way. I used the compressed air, after I'd washed and vacuumed the inside of the booth a couple of times, and with the extraction fan running, blew out all the nooks and crannies, fixtures and equipment. I kept going over and over every inch until the air was clear. I repeat this procedure before each batch of painting.
- Remove everything that doesn't need to be in the booth, seal/weatherstrip to make as airtight enclosure as possible. I even put duct tape on the doors.
- I went to Merv 10 filters, which slowed the airflow a bit, and created too much delta. So I added three more 25x20 filters to reduce the delta and tendency for air to be drawn through none-airtight/filtered locations.
- DO NOT use the Polyfiber C2210 pre cleaner as the manual says. This stuff was not inexpensive and caused me significant problems. There are several good alcohol-based pre-cleaners on the market including the one recommended to me by the Polyfiber tech department ... Prep Wipe (which arrived with a Polyfiber label on it). Alcohol/water cleaners have the added advantage of eliminating static which is a big plus when wiping down a large area. (I had the fuselage grounded in two places and still I was getting electric shocks from the surface as I was wiping it down. This static charge was surely attracting all the tiny particles in the vicinity too!, not to mention the obvious fire hazards.
- Ranthane needs to be reduced 50% or more for it to flow out nicely, but this also makes it sag-prone. This means three coats (as opposed to the two specified in the manual), one light, one medium and one full. 15-20 minutes between coats seems to work but I think this may be temperature dependent. For the red I applied 4 coats and waited 30 minutes between the first and second coats, 30 minutes between the second and third coats and 15 minutes between the third and final coat. This seemed to be a good recipe for the red but the white seemed to dry faster so I did 15 minutes between coats.
- The sooner you can apply the next coat the better the paint seems to flow, but too soon and it may sag or run away from rivet heads etc.
- 65-70 degrees seems to be a good temperature if you're lucky and have the ability to control temperature. Ranthane seems to flow a little better at cooler temperatures.
- I went down to a 1.3 tip on my gun and turned the air pressure up. 5-10 Psi more than the gun manufacturer says is normal. This definitely atomizes the paint better with a resulting improvement in finish. It also creates more over-spray so the extraction system needs to be able to keep up. More pressure also means higher flow rates so inline fittings, filters, hoses etc. need to be larger inside diameter.
- Take the time to wet-sand blemishes because Ranthane does not hide well.
- Leftover mixed paint can be put in the freezer and used the next day for small parts, inspection plates for example but I would tend to use freshly mixed paint for important surfaces because the viscosity of the stored mixed paint seems to be inconsistent.
I estimated how much paint I'd need for the particular job and mix up about enough for the first two coats. Then measure how much paint I actually used for the first and second coats. If necessary a little more paint can be mixed and added for the final coat. I added a little more reducer for the final coat as well.
Of course it's a two part product and if you get even a small amount of catalyst in the paint it's going to start to change. So keep everything clean and separate.
After all the experimenting with various small parts. I carefully wet-sanded the tail feathers to get rid of the fish eye, orange peel and contamination that resulted from my earlier attempt in the Spring.
Then set them up again in the paint booth for round two.
I also wanted a neat transition from the exterior finish and accent colours to the interior.
So I masked off the door frames and painted them the same JetGlo grey as the doors, forward door frames, and floors.
Also re-masked the windows after wet sanding the Polyspray edge.
Within 20 minutes of the final coat, the fine line tape is removed. This allows the edge to flow a little. It's easy to mess up the wet paint but I think its worth it for a better edge.
Such is the additional work requirement of three colours compared with two.
I leave the regulator set, but dismantling the guns each time for cleaning, means a new setup is needed each time.
Anyway I wet sanded after 48 hours or so and then shot an extra coat on the rivets, and another full wet coat, and a good result achieved.
Anyway these blemishes can be removed within 36 hours or so with methyl hydrate. It's a solvent for not fully cured urethane but won't hurt the fully cured finish.
Another solution, that works for harder to clean problems, is a tiny artist brush with a little white paint mixed but with no reducer.
My paint booth is now the Maroon Room!