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Author Topic: Understanding paint  (Read 2783 times)

Offline Shorts,David

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Understanding paint
« on: March 05, 2022, 11:47:35 PM »
Still getting more experience with paint. Nitrate with silkspan. Switched to butyrate primer and color. 100% Randolph. Then shot about 7 coats of clear butyrate. Things looked pretty promising. Never was able to get it to buff to a shine. Guess that's a lesson I still haven't learned. Oh well, flew it finally and now the plane is extra sticky where the fuel has been. Acts like glue and dirt from my hands mars the finish.
What'd I do wrong? Any way I can fix it?

Offline kevin king

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Re: Understanding paint
« Reply #1 on: March 06, 2022, 06:22:48 AM »
How long did you let the paint dry between coats?  How much time did you give the last coat of clear to dry & did you put a coat of Carnauba wax on before you flew it?  What nitro content are you using? Are you saying the fuel softened the paint or the exhaust residue? To fix it I would clean the airplane with a wax and grease remover then polish it back up to a shine, then put a coat of carnauba wax on it. Putting the fuel in the tank instead of on the finish also helps 😁. If that doesnt work you may want to consider using a 2 part automotive clear.
 
Kevin

Online Dennis Toth

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Re: Understanding paint
« Reply #2 on: March 06, 2022, 07:03:35 AM »
Dave,
As Kevin said first wipe down the whole ship with a degreaser/oil remover (like Sikkens degreaser m600). Next, wipe down with soapy water and let dry. At this point you need to let the paint gas off. Most dope needs a couple weeks after final coat to harden the surface to be able to buff. You might consider doing a coat of either KBS Diamond Clear Aerosol or SprayMax 2K Aerosol clear coat around the nose and area where raw fuel is likely to land to completely fuel proof. These materials require at least an N95 paint mask applied outdoors upwind.

Once the surface is hard you can start the buff out process. This takes a lot of 1200 sandpaper and elbow grease. Using either water or Windex spray a small area (like 6 -12" square) then take the 1200 paper (I like to fold it in 2" squares) and using a circular motion sand the surface. The objective is to get the surface smooth and flat. Once it is all smooth and dull you can take some white rubbing compound to the area and buff it out to see how the whole ship will look after buff out. Some have used silver polish as the final buff out. You can look for Windy U videos on buffing out for more details.

Best,   DennisT

Offline Shorts,David

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Re: Understanding paint
« Reply #3 on: March 06, 2022, 12:34:18 PM »
How long did you let the paint dry between coats?  How much time did you give the last coat of clear to dry & did you put a coat of Carnauba wax on before you flew it?  What nitro content are you using? Are you saying the fuel softened the paint or the exhaust residue? To fix it I would clean the airplane with a wax and grease remover then polish it back up to a shine, then put a coat of carnauba wax on it. Putting the fuel in the tank instead of on the finish also helps 😁. If that doesnt work you may want to consider using a 2 part automotive clear.
 
Kevin
Most of the clear I put on in pairs. Like a light coat everwhere, then immediately did a light coat everywhere again. Usually a couple days between those coats. No carnuba wax. I used meguilars paint polish stuff. Maybe that attacked my dope. My last plane I used the 2k aerosol on the dope. That worked fine, but I thought I'd try the traditional method this time and it's a big failure in my opinion. I've watched Windy's dope videos about three times. Thought I had it this time. Using 10% nitro.

I'll try the degreaser if I can find one in California.


Online Brett Buck

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Re: Understanding paint
« Reply #4 on: March 06, 2022, 01:23:08 PM »
Most of the clear I put on in pairs. Like a light coat everwhere, then immediately did a light coat everywhere again. Usually a couple days between those coats. No carnuba wax. I used meguilars paint polish stuff. Maybe that attacked my dope. My last plane I used the 2k aerosol on the dope. That worked fine, but I thought I'd try the traditional method this time and it's a big failure in my opinion. I've watched Windy's dope videos about three times. Thought I had it this time. Using 10% nitro.

I'll try the degreaser if I can find one in California.

      Dope is not fuelproof, it is, at best, fuel-resistant. And some types are more resistant than others, and no one seems to be able to tell which batch or brand is or isn't. Some batches of Brodak/Randolph are mostly OK, others, not resistant at all.

     This sort of thing is why most people went to synthetic materials like 2-part polyurethane for the clear. Some people, (the very unfortunately late) PTG used dope for the colors and 3-part polyurethane, Jim uses car colors and polyurethane, and I use epoxy colors ad polyurethane. David's airplane is mostly dope but has polyurethane  on parts of the fuselage for the reason you mention.

    Brett

Offline Shorts,David

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Re: Understanding paint
« Reply #5 on: March 06, 2022, 06:01:30 PM »
I'm trying some ZEP Heavy duty citrus cleaner. I tried it on the bottom of the stab and so far so good. Cleared it down really  nice. So, I guess I get a second chance. I have a 2 part auto clear on my shelf I was a bit nervous to try. Looks like I'll do that or some urethane or varathane. Upwind, respirator, walking backwards, etc.

Online Brett Buck

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Re: Understanding paint
« Reply #6 on: March 06, 2022, 06:40:16 PM »
I'm trying some ZEP Heavy duty citrus cleaner. I tried it on the bottom of the stab and so far so good. Cleared it down really  nice. So, I guess I get a second chance. I have a 2 part auto clear on my shelf I was a bit nervous to try. Looks like I'll do that or some urethane or varathane. Upwind, respirator, walking backwards, etc.

   
2-part clear is what you want.

  By the way, you didn't do anything "wrong" in the sense you mean it, this is what dope does and why some people have stopped using it. It's OK for electric, but, there is a lot better paint than dope that doesn't even have a pretense of fuel resistance.

    Brett

Offline Howard Rush

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Re: Understanding paint
« Reply #7 on: March 11, 2022, 01:15:37 PM »
Meh. Todd Lee liked Dope enough to win the 2021 Us Nats concours award.

Kenny Stevens and Paul Walker are also front-row dopesters, although Paul may have recently gone rogue. 

Butyrate dope is soluble in nitromethane.  "Fuel proof" is baldardash, but if you are careful, you can get away with finishing your plane in dope or even acrylic lacquer.

I'm told to use Certified dope, rather than Randolph, for final coats over color, but I have no personal experience with Certified.

I'm happy with two-part polyurethane clearcoat.
The Jive Combat Team
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Offline billbyles

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Re: Understanding paint
« Reply #8 on: March 14, 2022, 05:17:57 PM »
Still getting more experience with paint. Nitrate with silkspan. Switched to butyrate primer and color. 100% Randolph. Then shot about 7 coats of clear butyrate. Things looked pretty promising. Never was able to get it to buff to a shine. Guess that's a lesson I still haven't learned. Oh well, flew it finally and now the plane is extra sticky where the fuel has been. Acts like glue and dirt from my hands mars the finish.
What'd I do wrong? Any way I can fix it?

If done properly butyrate can me buffed to a beautiful gloss. I use butyrate for all my finishes (old school) and I have had two airplanes in the front row at the nats.  There is a learning curve associated with finishing with butyrate.
Bill Byles
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So. Cal.

Offline John Skukalek

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Re: Understanding paint
« Reply #9 on: March 27, 2022, 09:30:46 AM »
Is acrylic paint "glow fuel proof" ?

Online Dennis Toth

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Re: Understanding paint
« Reply #10 on: March 27, 2022, 06:08:14 PM »
Single component acrylic paints are not fuel proof, they are resistant but must cure out a couple weeks before being exposed to fuel. Max nitro ~10%. They are good if clear coat with 2 part clear.

Best,    DennisT

Offline John Skukalek

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Re: Understanding paint
« Reply #11 on: March 27, 2022, 07:45:53 PM »
Thanks Dennis. So clear coating with clear dope doesn't do it ?

Offline John Skukalek

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Re: Understanding paint
« Reply #12 on: July 14, 2022, 09:05:23 AM »
can dope be fuel proofed with Z Poxy?

Offline John Skukalek

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Re: Understanding paint
« Reply #13 on: July 14, 2022, 09:57:47 AM »
I should clarify. I have a model That I finished in dope a few years ago. It bleeds the dope on to rags when fuel or rubbing alcohol gets on the the surface. At this point can I put Z poxy over top of the surface finished in dope?   

Offline Shorts,David

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Re: Understanding paint
« Reply #14 on: July 15, 2022, 07:22:40 PM »
I still don't understand why the dope got so sticky, but I shot two part auto clear over it and sealed the thing like it never had a problem. Perhaps not perfect, but six months later or so it still has a smooth fuel proof finish. I'm doing dope again in a week, I'll see if I can keep it from going sticky this time.
 

Offline John Skukalek

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Re: Understanding paint
« Reply #15 on: August 08, 2022, 01:18:36 PM »
Is it possible to paint and fuel proof an airplane with rattle cans only?

Online Dan Berry

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Re: Understanding paint
« Reply #16 on: August 08, 2022, 03:59:49 PM »
Is it possible to paint and fuel proof an airplane with rattle cans only?

Yes. the clear that you'll want is about 30 bucks a can. SprayMax 2k.

Offline John Skukalek

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Re: Understanding paint
« Reply #17 on: August 08, 2022, 06:27:02 PM »
Thanks Dan. What types of color paint can the Spray Max 2K cover?

Offline Shorts,David

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Re: Understanding paint
« Reply #18 on: August 08, 2022, 06:29:52 PM »
I've used it over dope on an earlier project. I've used a different auto two part over Rust-Oleum.

Online Brett Buck

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Re: Understanding paint
« Reply #19 on: August 08, 2022, 07:37:16 PM »
Yes. the clear that you'll want is about 30 bucks a can. SprayMax 2k.

  You *do not want to know* how much a gallon of the real stuff cost Jim Aron and I.

     Brett

Online Dan Berry

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Re: Understanding paint
« Reply #20 on: August 10, 2022, 09:19:27 AM »
Thanks Dan. What types of color paint can the Spray Max 2K cover?

Just about anything is my understanding.

Offline Shorts,David

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Re: Understanding paint
« Reply #21 on: August 10, 2022, 11:54:39 AM »
  You *do not want to know* how much a gallon of the real stuff cost Jim Aron and I.

     Brett

My school custodian is also a custom paint shop guy. He told me what his clear costs. Same stuff I think. GULP!. I'll stick with my Finish 1 for now.

Online Dan Berry

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Re: Understanding paint
« Reply #22 on: August 10, 2022, 01:05:39 PM »
My school custodian is also a custom paint shop guy. He told me what his clear costs. Same stuff I think. GULP!. I'll stick with my Finish 1 for now.

I got a quart of clear plus hardener.
They gave me a serious discount --- like I was a paint shop-----. Basically 60 bucks. Enough for a lot of ukie planes. I assume 6-8 planes.
I got the discount because she understood that me and Joe Bowman are airplane nerds and it seemed obvious that she was sad for us.

Offline kevin king

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Re: Understanding paint
« Reply #23 on: August 10, 2022, 01:40:52 PM »
I still don't understand why the dope got so sticky, but I shot two part auto clear over it and sealed the thing like it never had a problem. Perhaps not perfect, but six months later or so it still has a smooth fuel proof finish. I'm doing dope again in a week, I'll see if I can keep it from going sticky this time.
  I recently decided to part with my tried and true method of Sig Dope and hardware store thinner. So i too am now noticing a stickiness with the paint a week later. It was Randolph insignia white dope and the recomended Randolph thinner. So far the only info i found on the dope not drying to a hard finish is from spraying to much at once. The Banshee i sprayed picked up 1oz of weight when i weighed it the next day. I did spray more than usual because the white was so translucent. Is that too much too spray at once? I think the amount sprayed was about 11oz total of the insignia white, and thats not including the 11 oz of thinner i used to reduce it. The Top IS white though, the bottom i intentionally put 1/3 less. It must take years to finish a full size plane with that kind of coverage. Gee whiz. I guess this is part of the reason that I am reluctant to try new finishing methods. My method worked for me, but may not work for anyone else. Knowing the product and process must be a larger factor than i thought. Hopefully the white will dry. Maybe leaving it in the car a few hours will work. Hopefully someone can chime in on what to do.
« Last Edit: August 10, 2022, 02:02:28 PM by kevin king »

Offline Shorts,David

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Re: Understanding paint
« Reply #24 on: August 10, 2022, 02:11:32 PM »
My plane between the sticky one and the one I'm doing now is all Rustoleum paint with auto clear on top. I read Ken Culbertson's tips and also Charles's pointers he's posted and it is sooooo much easier, I may go back to that method, but at the moment, I still don't have a process I'm satisfied with other than a couple of my ultracote planes turned out very nice (by my standard). But they were 100% ultracote.

I'm trying dope again, possibly just because I bought nearly $200 of the stuff from Aircraft Spruce. Whoops. My rustoleum job was about $25 plus clear.

And, the white was terrible. I've never painted straight white. So many coats to get it to look white. Well, I'm committed now.

Offline Matt Colan

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Re: Understanding paint
« Reply #25 on: August 12, 2022, 09:11:57 PM »
  I recently decided to part with my tried and true method of Sig Dope and hardware store thinner. So i too am now noticing a stickiness with the paint a week later. It was Randolph insignia white dope and the recomended Randolph thinner. So far the only info i found on the dope not drying to a hard finish is from spraying to much at once. The Banshee i sprayed picked up 1oz of weight when i weighed it the next day. I did spray more than usual because the white was so translucent. Is that too much too spray at once? I think the amount sprayed was about 11oz total of the insignia white, and thats not including the 11 oz of thinner i used to reduce it. The Top IS white though, the bottom i intentionally put 1/3 less. It must take years to finish a full size plane with that kind of coverage. Gee whiz. I guess this is part of the reason that I am reluctant to try new finishing methods. My method worked for me, but may not work for anyone else. Knowing the product and process must be a larger factor than i thought. Hopefully the white will dry. Maybe leaving it in the car a few hours will work. Hopefully someone can chime in on what to do.

I have had excellent success with the Randolph products and Home Depot thinner. Coverage is excellent except yellow and white, but way better than any other dope product I’ve used. White over a gray base takes about three coats and I put on 3oz on a 75 sized airplane. I thin my paint 60% thinner. Adhesion has been so good I joke I could use duct tape and the paint wouldn’t pull up. After all colors I spray auto clear over the top

I too have been thinking of trying something different and going to Klasskote or auto colors but I find it hard to change given the success
Matt Colan

Offline Steve Helmick

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Re: Understanding paint
« Reply #26 on: August 14, 2022, 08:25:24 PM »
A few years ago, it was reported that Brodak clear was less fuel resistant than SIG clear, so a lot of dopesters used Brodak dope but SIG clear over it. I'd wonder if David was using some of the older Brodak clear, from before they changed the formulation to fix that problem?   ??? Steve
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Offline John Skukalek

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Re: Understanding paint
« Reply #27 on: August 15, 2022, 08:08:15 AM »
So has Brodak Clear been changed so that it is fuel prroof?

Online Brett Buck

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Re: Understanding paint
« Reply #28 on: August 15, 2022, 09:14:27 AM »
So has Brodak Clear been changed so that it is fuel prroof?

  I don't know, but no dope is fuel proof, it is fuel resistant at best. You still have to be very careful if you get raw fuel on it and wipe it up immediately.

     Brett

Offline John Skukalek

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Re: Understanding paint
« Reply #29 on: August 15, 2022, 09:31:28 AM »
Thank you Brett

Offline kevin king

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Re: Understanding paint
« Reply #30 on: August 20, 2022, 11:45:43 PM »
I once seen a plane that looked like it had one coat of color dope brushed on it. I could see the color wood underneath it.  Just saying. The less coats the less fuel resistance.  One coat of sig Light coat will not be more fuel proof than 15 coats of Brodak clear. And as I think Brett once pointed out, the quality of the same products can vary as well.

 


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