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Building Tips and technical articles. => Paint and finishing => Topic started by: DanielGelinas on January 06, 2017, 05:05:13 PM
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Hi guys,
First off, I would like to wish you all a great new year!
I am having what seems to be a little problem with spraying orange dope.
I now have four coats sprayed on and it looks as if four more still won't be enough😕.
Will the plane be very heavy by the time I have ten-twelve coats on🤔.
This is my FIRST experience spraying a plane. Always used the brush before.
Dope is Brodak cessna orange. I did not spray a cote of silver before because I was concerned with weight...
Thanks for any tips!
Regards,
Dan
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I am curious about an answer here too.
I sprayed Sig Cub Yellow dope over Sig Silver awhile back and had problems getting the yellow to cover. Took too many coats and ended up heavier than I desired. I figured the dope was old (15 years), maybe not mixed thoroughly enough and sprayed at too high a pressure. In my case, when magnified, the silver had a "sintered metal" look to it and I thought the pigment might have kept going to the bottom of the silver coat leaving silver peaks shining through. The silver pigment might have been clumped and splattered out at too high a pressure. Not my best work, but not on a CL plane.
I understand Red and Yellow are hard to get good coverage. Would it help to put a clear coat over the silver? Would a different base coat (white?) help these colors cover better?
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Y ou should use a light coat of white primer Brodak sells it for real red. yellow. orange colors dark base colors take too much paint to cover and also darken final colors.
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I have had trouble with Brodak Cessna Orange. It does not appear to have much pigment. When I got back into the hobby one of my first planes was painted orange over Polar Gray that I used as a primer. It eventually covered OK but the orange did not have the "brilliance" I expected. If I had used silver as a primer I might have had similar results.
Brushing on the orange did not work at all for me. Even when thinned and with some retarder added I ended up with many brush marks and it took many coats to cover. It ended up looking lumpy.
Now, I first apply white instead of gray. Colors like yellow, red, orange stand out better when applied over white. The Brodak Lemon Yellow trim I used a few times covered pretty well with only two sprayed coats when applied over white.
The orange (sprayed) covered better when applied over white but still not as well as I would like. I was tempted to get the Randolph brand and see if it covered better than the Brodak.
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I have had trouble with Brodak Cessna Orange. It does not appear to have much pigment. When I got back into the hobby one of my first planes was painted orange over Polar Gray that I used as a primer. It eventually covered OK but the orange did not have the "brilliance" I expected. If I had used silver as a primer I might have had similar results.
Brushing on the orange did not work at all for me. Even when thinned and with some retarder added I ended up with many brush marks and it took many coats to cover. It ended up looking lumpy.
Now, I first apply white instead of gray. Colors like yellow, red, orange stand out better when applied over white. The Brodak Lemon Yellow trim I used a few times covered pretty well with only two sprayed coats when applied over white.
The orange (sprayed) covered better when applied over white but still not as well as I would like. I was tempted to get the Randolph brand and see if it covered better than the Brodak.
Thanks for the info on cessna orange. From what I have read on the forum, Randolph makes Brodak paint, so I'm not sure you would see any difference.
Now..., should I keep on keepin on with the orange -OR- put a white cote right away, then the orange...
That is the question I need to ask myself. ??? ::)
Regards,
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Yes, Randolph makes Brodak dope but there could be differences. For example, I have found the Randolph non-tautening clear to have more fuel resistance than the Brodak clear, either the regular Brodak clear or the Crystal Clear. From what I have seen, the Crystal Clear has minimal fuel resistance. That does not mean the Randolph clear is fuel proof, just more resistant.
So, maybe some of the colors are different as well regarding pigment content. Not likely, but maybe. I have not looked into it yet to compare the two.
I cannot say if you should apply some white at this time then more orange. Maybe you can try it on a small area or make up some scrap pieces and give it a try before attempting it on the entire plane.
Many times I have noticed that repeated coats of some colors will cause "darkening" but never appearing completely opaque. We might simply have to accept that and move on or try another finishing method.
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I'll repeat this here as a possible idea to keep in mind should things go off the rails. I've used a roll of paper towels and a gallon of the local DIY store lacquer thinners to carefully wash/wipe away a dope finish that had gone south. With care you can control your application and you'd be amazed at how fast you can take a model down to the silk span.
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Thanks for the tips guys.
I think IF the cessna orange is missing pigment, it may be also missing the extra weight.
So, I think I'll just continue with a few more cotes of orange.
BTW, the dope is NOT sprayed on the wing. The wing is monocoted.
Regards,
Dan
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Daniel,
You don't have to use colored dope to finish a model nicely.
I've read so many negative comments, just like yours, about issues and problems with colored dope, that I've elected early on NOT to use it. At all.
There isn't one speck of colored dope on any one of these models.
Works for me and could work for anyone else.
Charles
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I use a lot of colored dope. The last plane I completed was orange and won an award at last years VSC. Orange covers better than red, yellow or light blue but still needs a base of white or very, very light grey (white with a few drops of polar grey to get better coverage). Brodak dope has more pigment than Sig but both work well. Since you have only painted the wood my suggestion is to let it cure a few weeks than sand it down so that it is very thin but not to the wood. Use 500 or 600 sandpaper and a sanding block made of balsa or rubber (available at good paint stores) It should smooth out nicely. Then a coat of white (I know, white cement...whatever). You should only need one coat and it won't have to be thick. If a few places look thin, touch up, don't re-spray the whole plane. Spray your orange on top of that then finish with two or three coats of clear for a "sport" finish. Polish lightly. This will look better then umpteen coats of orange and be lighter as well. Good luck. 8)
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You have to mix it up really well to get the pigment off the bottom.
And, as they say, red & yellow are transparent and need white base coat. I did OK with orange by itself. But maybe I'll base coat that too.
Brush painting is a losing deal unless you use just one color. The second color will dissolve the base coat if you try to brush over it.
I like to take the quart can to Home Depot & get them to re-shake it. Then I pour a few ounces into a thinning jar so I don't have to mess with the quart all the time.
I wash the sprayer parts in thinner, using an old shot glass. Then I dump the used thinner back into the thinning jar. Zero waste.
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I used Randolph orange on my orange Bearcat and had no problems with coverage and I thinned it a lot. 60% thinner at least.
I am adding this picture of my Falcon for JIm as I could not send it in the email on here.The orange was put over doped wood with no primer or white
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I use a lot of colored dope. The last plane I completed was orange and won an award at last years VSC. Orange covers better than red, yellow or light blue but still needs a base of white or very, very light grey (white with a few drops of polar grey to get better coverage). Brodak dope has more pigment than Sig but both work well. Since you have only painted the wood my suggestion is to let it cure a few weeks than sand it down so that it is very thin but not to the wood. Use 500 or 600 sandpaper and a sanding block made of balsa or rubber (available at good paint stores) It should smooth out nicely. Then a coat of white (I know, white cement...whatever). You should only need one coat and it won't have to be thick. If a few places look thin, touch up, don't re-spray the whole plane. Spray your orange on top of that then finish with two or three coats of clear for a "sport" finish. Polish lightly. This will look better then umpteen coats of orange and be lighter as well. Good luck. 8)
Thanks Pete,
I think that is what I will do. These are sport planes so I really am not looking for a 20 point finish. just coverage so I can't see pencil marks and whatnot...
Regards,
-Dan
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Daniel,
You don't have to use colored dope to finish a model nicely.
I've read so many negative comments, just like yours, about issues and problems with colored dope, that I've elected early on NOT to use it. At all.
There isn't one speck of colored dope on any one of these models.
Works for me and could work for anyone else.
Charles
Hi Charles,
Just what are you using to replace colored dope?
Détails please!
Regards,
-Dan
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You have to mix it up really well to get the pigment off the bottom.
And, as they say, red & yellow are transparent and need white base coat. I did OK with orange by itself. But maybe I'll base coat that too.
Brush painting is a losing deal unless you use just one color. The second color will dissolve the base coat if you try to brush over it.
I like to take the quart can to Home Depot & get them to re-shake it. Then I pour a few ounces into a thinning jar so I don't have to mess with the quart all the time.
I wash the sprayer parts in thinner, using an old shot glass. Then I dump the used thinner back into the thinning jar. Zero waste.
Thanks for the tips Paul!
Regards,
-Dan
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Hi Charles, Just what are you using to replace colored dope? Détails please!
Regards,
Dan
Dan,
Thanks for the interest. I suggest you search the Forum for my Build or Finishing Threads.
Every one of those models are featured in build and finishing Threads and I mention all products.
Some are over at CFC Graphics vendor's corner and the others are scattered in the main Forum.
As I said, a search should bring them up.
Charles
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In answer the the original question, with dope especially, when you plan on yellow, orange, or red, you MUST spray a coat of very light grey ( or white, but it will take more white to cover)
The point is, it will not help the color cover better, but it will prevent the colors and marks from showing through. The basic goal is to make sure the undercoat is all one color.
Silver under yellow makes a greenish yellow that is not all the pleasant..
and it will whack out orange too,, Red would probably be safe over silver...
Hence my suggestion for white.
Were I in your position, I would resand the airframe with 400 to remove the majority of what you applied, this will also help make it a better finish. Then spray white or white with a few drops of black added to make a light grey, then start over with the orange , I think you will ultimatly be happier
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I think you will ultimatly be happier
I am even happier as a painter of orange airplanes following Mark's advice to use PPG polyurethane.
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I am even happier as a painter of orange airplanes following Mark's advice to use PPG polyurethane.
OK howard,
What is PPG?
Thanks,
Dan
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PPG is a brand name of Really Good auto refinishing paint. I'm not sure if you'll want to mess with it just for sport modeling.
If Mark hadn't gotten on yet I was going to tell you what he said, with the rider that "if Mark Scarborough says different, believe him". So -- believe Mark.
Sand it down, paint it white, paint color on the white. You'll be happy. In the future, if you're just looking for a "sport plane" level of quality, you might want to use Rustoleum, either out of a rattle-can or sprayed through a sprayer. The best Rustoleum finish will never be as good as the best dope finish, and it's easy to make things heavy, but a half-assed Rustoleum finish is easier than a half-assed dope finish. It's up to you.
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Be nice, Mark.
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And I will note that Red, Orange and Yellow are transparent colors. As Mark notes, you do well to put some sort of undercoat to aid the color in covering. And also as Mark notes, the color you chose as an undercoat will effect the ultimate color. With red, for instance, use some sort of red oxide primer works better (or black as a base). Yellow and Orange will brighten considerable with a white undercoat. I've used gold and an undercoat for yellow and it makes it not quite so bright.
As always, every coat you put on is adding weight so it's always a good idea to limit the number of coats. You can also put additional pigment into whatever color you are choosing to give it better covering ability, I do this with white.
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Be nice, Mark.
but I was nice!!
After all the times I suggested he use the search function, and have him bad mouth and rail me for not being helpfull I find it hilarious that he is suggesting using the search function now,
come on, you have to see the irony and humor right? D>K
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"With red, for instance, use some sort of red oxide primer works better (or black as a base)."
Randy...to be clear...did you mean that red over black undercoat works well? ??? Steve
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He means red over black. Whatever is used for an undercoat and becomes a block for other colors bleeding through. That's why it's often called a "blocking coat".
Obviously a black undercoat will yield a darker top coat. With modern two-stage polyurethanes the problem isn't nearly as bad, as in nearly nonexistent. The only reason I haven't switched to it is because I have a fairly large supply of Randolph dope to use up.
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He means red over black. Whatever is used for an undercoat and becomes a block for other colors bleeding through. That's why it's often called a "blocking coat".
Obviously a black undercoat will yield a darker top coat. With modern two-stage polyurethanes the problem isn't nearly as bad, as in nearly nonexistent. The only reason I haven't switched to it is because I have a fairly large supply of Randolph dope to use up.
Mike,
You wouldn't have any problem selling your dope then you could start using an auto base coat clear coat system.
Tons of guys probably are they just don't broadcast or they don't Post.
I was an early starter with using auto base coat clear coat systems on my models.
I painted this pattern ship back in the early 80's. I bet I get plenty of compliments. LL~ LL~ LL~
Lets see, scratch built, sheeted foam wings, I even cut the foam cores, glass cloth covered, and finished with all auto paints.
Hand applied 23K gold leaf lettering, shadowed and outlined with One-Shot sign painter's enamel. British graphics are Don's brushing lacquers.
Lots of work and worth every bit of it.
My Avenger was the people's choice award for "Best Finish" at the WRAM show. Over the years I must have painted a couple of dozen models using all automotive products.
Now I just use aerosol cans and sometimes an air brush using plastic modeler's water base paints. I always clear with a 2K auto paint, in an aerosol can.
It's the easy way out but it gets the job done. I do Sport anyway.
Here's the model.
I'm sure it will be well received.
Charles
Anyway, for those that have never seen this photo, and my guess there's plenty,
The Avenger,
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Randy said it all. I always have white under transparent colors like Red Orange or Yellow.
Ed, Your Falcon looks great. I didn't know that you were building one.
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Just to be clear, I didn't say that I don't like dope, and I will what I have. For me, it is easy to use, easy to repair, (I fly my planes, a lot) and is lighter than poly. I've use about everything, including water borne polyurethane. Dope is still better, for me. You just have to follow some rules.
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Just to be clear, I didn't say that I don't like dope, and I will what I have. For me, it is easy to use, easy to repair, (I fly my planes, a lot) and is lighter than poly. I've use about everything, including water borne polyurethane. Dope is still better, for me. You just have to follow some rules.
Mike,
Understandably. I think there are advantages with dope for the people that enter contest especially where light models are a necessity. Just a guess.
For Sport guys like myself I'll continue to do what I do.
Dope isn't the easiest product to master, but when it is, the finishes can be outstanding. I go over to the Gallery from time to time and view the models, some with world class finishes.
Absolutely worth the look.
Charles