Why isn't my Butyrate Dope (Brodak) glossy??
#1
Member
Thread Starter
Why isn't my Butyrate Dope (Brodak) glossy??
I am testing my Butyrate Dope (Brodak) on a small frame sample of Silkspan before brushing onto the new wing covering. It is "Cessna White" but dries to a flat, dull off white color. Where is the gloss, and how do I get that?
As a kid, all the dope was just painted on (airplane and ship models) and always dried to a shiny surface??
I'm not trying to be a "perfectionist", as I expect the plane to crash as I re-learn how to fly it again after 50 years, but do want a mode I can be proud of!!
Thanks for any insight.
aaganz
As a kid, all the dope was just painted on (airplane and ship models) and always dried to a shiny surface??
I'm not trying to be a "perfectionist", as I expect the plane to crash as I re-learn how to fly it again after 50 years, but do want a mode I can be proud of!!
Thanks for any insight.
aaganz
#2
My Feedback: (2)
Butyrate dope is generally a non glossy finish. When used on full size airplanes, its the finish Cubs, Champs and the like had. That's why so many rebuilders like the urethanes (Air Tech is popular theses days). For models, a shiny finish on dope was traditionally done by hand rubbing using rubbing compound. It's a time consuming process, but the results can be stunning. Many switched to clear-coating to save all that hard work. I actually like the not quite glossy finish of dope on my silkspan covered models.
#3
I replied to your other thread but I will say something here as well. Hag is on point about the hand rubbed finish. One thing about high gloss is that you are laying on enough paint to fill the grain of the silkspan plus enough to sand it to a super smooth finish. It is easy to add a significant amount of weight with a super glossy paint job.
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hag (03-24-2024)
#4
Member
Thread Starter
Thanks to Hag and Matt. Rubbing would need too many layers of dope. I have ordered 4 oz of clear dope, and will add that on at the end with some thinner and hope for a reasonably glossy finish! I want a nice looking plane in the event it only gets a few demonstration flights!
aaganz
aaganz
#5
Member
Thread Starter
All,
I posted the question to Brodak, and they replied today. They said to apply 2-3 coats of clear butyrate dope over the color dope, and that would do it. The shipment pf clear dope will be here in a day or so, and I can test it on my "test frame sample".
aaganz
I posted the question to Brodak, and they replied today. They said to apply 2-3 coats of clear butyrate dope over the color dope, and that would do it. The shipment pf clear dope will be here in a day or so, and I can test it on my "test frame sample".
aaganz
#6
Senior Member
I have always used Randolph dope Nitrate And Butirate, temperature is important 70 degrees is about right, use retarder and a little MEK or Tauall in the mixture. Always have a nice gloss, AJ
#7
Member
Thread Starter
All,
I am trying out the clear dope Brodak just sent me. Form various YouTubes, I see that some paints are intended to be put on in (at least ) 2 layers. The bottom layer is the "color layer", and the outer layer is the "gloss layer". I never did this in 2 steps as a kid....we just put on whatever dope came from the local hobby store.
See my next post with pix of the plane (1953) , as retrieved from the attic last month.
aaganz
I am trying out the clear dope Brodak just sent me. Form various YouTubes, I see that some paints are intended to be put on in (at least ) 2 layers. The bottom layer is the "color layer", and the outer layer is the "gloss layer". I never did this in 2 steps as a kid....we just put on whatever dope came from the local hobby store.
See my next post with pix of the plane (1953) , as retrieved from the attic last month.
aaganz
#8
The "clear/base" is primarily an automotive paint thing. But it does work with dope. For the purposes of polishing and gloss dope is essentially a lacquer. As long as your dope is specifically "clear gloss" you should be able to achieve a nice finish. Multiple thinned coats are better than one heavy one. As modelers we are relatively lucky. Just for perspective, I have a aircraft repair manual from the 1940's. It describes 19 coats of dope for a high quality covering job.
#9
Senior Member
How did you guys ended up with some gloss in your dope? I recently decited, to go order a quart of silver dope. Kinda having a difficult time getting good coverage getting lite streaks in my Maroon even the Metalic Maroon is streaking. Figure brushing is out. And I will go to my Develbus top loader. HVLP touch up gun.
#10
How did you guys ended up with some gloss in your dope? I recently decited, to go order a quart of silver dope. Kinda having a difficult time getting good coverage getting lite streaks in my Maroon even the Metalic Maroon is streaking. Figure brushing is out. And I will go to my Develbus top loader. HVLP touch up gun.
#11
Member
Thread Starter
All,
I am getting a good gloss with the Brodak Clear Dope brushed over the Cessna White Dope. At first the brush strokes stood out as "streaks", but then filled in gradually to a smooth finish. I am now brushing on the "yellow stripes" on the wing and elevator, just as the original plane was years ago. Then will cover it all with Clear Dope....I am checking there are no interactions among all the dopes!
When the RCuniverse system allows, (failed so far!!) I will post a pix of the old, torn up, CL plane. I do want to know what it was ....obviously popular in the mid 1950s
aaganz
I am getting a good gloss with the Brodak Clear Dope brushed over the Cessna White Dope. At first the brush strokes stood out as "streaks", but then filled in gradually to a smooth finish. I am now brushing on the "yellow stripes" on the wing and elevator, just as the original plane was years ago. Then will cover it all with Clear Dope....I am checking there are no interactions among all the dopes!
When the RCuniverse system allows, (failed so far!!) I will post a pix of the old, torn up, CL plane. I do want to know what it was ....obviously popular in the mid 1950s
aaganz
#12
Senior Member
Ya that's happened to me to. Glad she smoothed out. I just ordered a quart of Silver non taughting dope need to do more fill, not really concerned about added weight. Like a slow circle getting old for this S***. But really enjoy the circle. And keeping my lines tight!!!!AJ.
#13
Ya that's happened to me to. Glad she smoothed out. I just ordered a quart of Silver non taughting dope need to do more fill, not really concerned about added weight. Like a slow circle getting old for this S***. But really enjoy the circle. And keeping my lines tight!!!!AJ.
Has anyone touched on humidity and dope? Dope and other lacquers will sometimes blush (take on a whitish haze) if the humidity is high. Unless it is really bad it will generally clear over a couple of days as the dope continues to dry.
#14
The two things that contribute to blushing are high humidity (as was already mentioned) and solvents in the dope (lacquers) that evaporate too quickly, causing moisture to be trapped in the paint. The solution is to use a "retarder" (low grade thinner) to slow the rate at which the paint dries. Years ago companies like Testors, and Aero Gloss sold retarders, but I don't think any model dope supplier does so today. A good automotive paint supplier should have compatible retarders.
#16
My Feedback: (6)
Wow, you learn something every day! I thought colored dope was used more as a primer base instead of an actual finish. I had applied about an entire gallon of Brodak butyrate dope in many coats onto an 89" koverall covered plane and kept sanding between coats until the cloth and dope was sealed and smooth. Then with a spray gun I applied coats of fuel proof primer, sanding the primer, then applying final top coat paint for a nice finish.
I never knew colored dope would dry with a deep enough pigment to look good....and always thought it was used more for colored primer purposes.
I never knew colored dope would dry with a deep enough pigment to look good....and always thought it was used more for colored primer purposes.
#17
Wow, you learn something every day! I thought colored dope was used more as a primer base instead of an actual finish. I had applied about an entire gallon of Brodak butyrate dope in many coats onto an 89" koverall covered plane and kept sanding between coats until the cloth and dope was sealed and smooth. Then with a spray gun I applied coats of fuel proof primer, sanding the primer, then applying final top coat paint for a nice finish.
I never knew colored dope would dry with a deep enough pigment to look good....and always thought it was used more for colored primer purposes.
I never knew colored dope would dry with a deep enough pigment to look good....and always thought it was used more for colored primer purposes.
#18
Senior Member
All of this is great info, been using a Dope finish for over seventy years and not much has changed when you talk about a Dope finish. I use a lot of retarder and have relied on Randoph Dope for many years. My early years I got Dope out of a drum at the Af Base. Also the Thinner don't think it was retarder because every once in a while it would blush. Mostly in Winter temps Washington State we got a lot of rain. Now my home is Texas and plenty of humidity. So the retarded works well and I use it by the gallon. Again Randolph. You can save buying it in the gallon. And I buy a quart of the Color. That also saves. I also have bought pints from Sig, of color but that's also blowing money. AJ
#19
I am testing my Butyrate Dope (Brodak) on a small frame sample of Silkspan before brushing onto the new wing covering. It is "Cessna White" but dries to a flat, dull off white color. Where is the gloss, and how do I get that?
As a kid, all the dope was just painted on (airplane and ship models) and always dried to a shiny surface??
I'm not trying to be a "perfectionist", as I expect the plane to crash as I re-learn how to fly it again after 50 years, but do want a mode I can be proud of!!
Thanks for any insight.
aaganz
As a kid, all the dope was just painted on (airplane and ship models) and always dried to a shiny surface??
I'm not trying to be a "perfectionist", as I expect the plane to crash as I re-learn how to fly it again after 50 years, but do want a mode I can be proud of!!
Thanks for any insight.
aaganz
Last edited by search-n-destroy; 07-11-2024 at 11:43 AM.
#20
How many coats did you brush on? How much did you thin the dope? what kind of thinner did you use? What kind of covering did you use? My guess is you didnt apply enough paint or the humidity was too high.
#21
Member
Thread Starter
Thanks for the insight! I went ahead with the doping of the main wing covering! Here are the 7 steps I followed on the top!
1. 30% EzeDope, 70% Water
2. 40% White, 60% Thinner
3. 40% White, 60% Thinner
4. 60% White, 40% Thinner
5. 90% White, 10% Thinner
6. 60% Clear, 40% Thinner
7. 60% Clear, 40% Thinner
This came out pretty nicely, except for some streak marks that I covered with 100% Lemon Yellow stripes!!
This was a lot more effort than I ever expended as a kid!
aaganz
1. 30% EzeDope, 70% Water
2. 40% White, 60% Thinner
3. 40% White, 60% Thinner
4. 60% White, 40% Thinner
5. 90% White, 10% Thinner
6. 60% Clear, 40% Thinner
7. 60% Clear, 40% Thinner
This came out pretty nicely, except for some streak marks that I covered with 100% Lemon Yellow stripes!!
This was a lot more effort than I ever expended as a kid!
aaganz