Go Back  RCU Forums > RC Airplanes > Kit Building
Reload this Page >

Fuel proof paint alternatives?

Notices
Kit Building If you're building a kit and have questions or want to discuss kit building post it here.

Fuel proof paint alternatives?

Old 02-06-2020, 05:42 PM
  #1  
TimJohansen
Junior Member
Thread Starter
 
TimJohansen's Avatar
 
Join Date: Jan 2020
Posts: 17
Received 0 Likes on 0 Posts
Default Fuel proof paint alternatives?

Hello!
I am having a hard time finding fuel proof Dope (I believe Pactra is no more) ..
Sig is backordered...
are there any alternatives?
Thank you👍
Old 02-06-2020, 09:18 PM
  #2  
skylark-flier
 
skylark-flier's Avatar
 
Join Date: Sep 2002
Location: VA, Luray
Posts: 2,152
Received 5 Likes on 5 Posts
Default

Pactra's been gone for awhile. My best advice would be Brodak, and their dope all seems to be on clearance, roughly half-off normal price right now.

Here's a link to their 16 oz. cans: https://brodak.com/clearance/dope-16-oz-on-sale.html
The following users liked this post:
TimJohansen (02-07-2020)
Old 02-06-2020, 09:42 PM
  #3  
gyrocptr
 
Join Date: Jul 2006
Location: Neenah, WI
Posts: 136
Likes: 0
Received 2 Likes on 2 Posts
Default

https://www.aircraftspruce.com/menus...hcoatings.html

Randolph aircraft dope.
The following users liked this post:
TimJohansen (02-07-2020)
Old 02-07-2020, 04:44 AM
  #4  
rgburrill
 
rgburrill's Avatar
 
Join Date: Dec 2010
Location: Dallas, Tx CT
Posts: 2,446
Received 28 Likes on 27 Posts
Default

As I recall paint itself does not need to be fuel proof. I've always used Rustoleum and some have recommended Krylon. It's the primer that needs to be fuel proof because that is what touches the wood. And for that I've used Tower. But a quick look on the Tower website shows that, too, is gone. Horizon just doesn't care about kit building any more.
Old 02-07-2020, 05:23 PM
  #5  
TimJohansen
Junior Member
Thread Starter
 
TimJohansen's Avatar
 
Join Date: Jan 2020
Posts: 17
Received 0 Likes on 0 Posts
Default

Thank you👍
Old 02-07-2020, 05:24 PM
  #6  
TimJohansen
Junior Member
Thread Starter
 
TimJohansen's Avatar
 
Join Date: Jan 2020
Posts: 17
Received 0 Likes on 0 Posts
Default

Many thanks!
Old 02-08-2020, 03:31 AM
  #7  
RBACONS
My Feedback: (3)
 
Join Date: May 2005
Location: Vero Beach, FL
Posts: 600
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by rgburrill View Post
As I recall paint itself does not need to be fuel proof. I've always used Rustoleum and some have recommended Krylon. It's the primer that needs to be fuel proof because that is what touches the wood.
I think this is backwards. If the paint/dope is not fuel proof, its the top coat (i.e. clear coat) not the primer, that needs to be fuel proof.
Old 02-08-2020, 05:00 AM
  #8  
rgburrill
 
rgburrill's Avatar
 
Join Date: Dec 2010
Location: Dallas, Tx CT
Posts: 2,446
Received 28 Likes on 27 Posts
Default

Originally Posted by RBACONS View Post
I think this is backwards. If the paint/dope is not fuel proof, its the top coat (i.e. clear coat) not the primer, that needs to be fuel proof.
I thought so too but was taught differently years ago. Rustoleum and Krylon don't have an issue with fuel, especially if you clean your model when you are done for the day. But balsa and plywood do, that's why firewalls and fuel tank areas are fuel proofed. I only used dope a few times many, many years ago with tissue paper, rubber band models so I don't know about them.
The following users liked this post:
TimJohansen (02-08-2020)
Old 02-08-2020, 07:53 AM
  #9  
tedsander
 
Join Date: Jul 2004
Location: White Bear lake, MN
Posts: 403
Likes: 0
Received 25 Likes on 25 Posts
Default

Originally Posted by rgburrill View Post
I thought so too but was taught differently years ago. Rustoleum and Krylon don't have an issue with fuel, especially if you clean your model when you are done for the day. But balsa and plywood do, that's why firewalls and fuel tank areas are fuel proofed. I only used dope a few times many, many years ago with tissue paper, rubber band models so I don't know about them.
Yes, the wood degrades if fuel soaks in. So needed is putting a barrier on it to prevent that from happening. So the search is on to find a barrier that also won't degrade when fuel hits it.
Epoxy, polyester resin, and a few (now rare) kinds of paint all serve that purpose for wood.
Unfortunately, it is not just the nitro that attacks some paint, it is the alcohol too! And Rustoleum just doesn't stand up to it. I repainted my transmitter case with Rustoleum engine paint just last year, based on on-line comments that it would work (it's for car engines, right?). But, after a day of flying, it would start to feel "sticky". Even though I used a towel to wipe my hands after refueling a glow engine, there was enough residue on the fingers to attack the paint. Same thing happened if I used Windex to clean it - or any other Rustoleum paint on the plane. The color begins to wipe right off on the cleaning towel, and the surface gets sticky, and stays sticky for a few days. Same happens to Krylon that I tried. In doing the research, it seems it may depend on how "old" the formulation is, and sometimes even on what color it is.
Butyrate dopes are "fuel resistant". "Klass Kote" epoxy paint is currently the best, but expensive. I've seen posts about other paints - auto paint, even house paint...but have not done the testing to see what else may work.
It seems like the availability is small, and getting smaller, with each passing day....
Old 02-08-2020, 08:48 AM
  #10  
TimJohansen
Junior Member
Thread Starter
 
TimJohansen's Avatar
 
Join Date: Jan 2020
Posts: 17
Received 0 Likes on 0 Posts
Default

Thank you so much for the info. Here in CA it is soooo difficult, as none of the Dope products are sold...EPA rules are very tough ....
Old 02-08-2020, 08:01 PM
  #11  
52larry52
My Feedback: (1)
 
Join Date: May 2009
Location: Ocala, Florida
Posts: 1,282
Likes: 0
Received 0 Likes on 0 Posts
Default

I think it's Krylon that sells an epoxy appliance paint (spray cans) that is fuel proof. Only thing is that it only comes in 3 colors, black, white, and an off white cream. WalMart sells it here in Ocala, Florida.
Old 02-17-2020, 07:45 AM
  #12  
SA Flyer
My Feedback: (3)
 
SA Flyer's Avatar
 
Join Date: Jun 2002
Location: SAN ANTONIO, TX
Posts: 144
Received 1 Like on 1 Post
Default

From Auto Zone, I tried the Duplicolor Clear coat, and it, too, gets sticky and stays sticky after 15% fuel was spilled on it. It's been 3 months since fuel fell on it, and it still is sticky to the touch.
KlassKote would be nice but it does not come in spray cans. I don't want to buy spraying equipment. I have enough stuff in the work shop that stands for long periods of time before the next use.
For my airplane sizes of 60-70" planes, I have been considering moving to small gas engines. An expensive solution that will have to wait a while.
Recently, I come across two websites, but have not explored them well to make a decision
LVP Paints https://www.lvppaints.com/
WingsWest Home

Last edited by SA Flyer; 02-17-2020 at 05:01 PM.
Old 02-17-2020, 04:25 PM
  #13  
TimJohansen
Junior Member
Thread Starter
 
TimJohansen's Avatar
 
Join Date: Jan 2020
Posts: 17
Received 0 Likes on 0 Posts
Default

Thank you for taking the time sending me this info. You are sincerely appreciated!
Going to try Brodak...hoping they ship out to CA.
Old 02-18-2020, 11:01 AM
  #14  
paulinfrance
 
Join Date: Jan 2010
Location: ales, QC, FRANCE
Posts: 77
Received 1 Like on 1 Post
Default

I use mat / brilliant Polyurethane 2 pack car varnish, it won't budge weathers it's methanol / petrol / jet fuel, and it will Harden in Under 15c temperatures.
The following users liked this post:
TimJohansen (02-18-2020)
Old 06-04-2020, 11:53 AM
  #15  
sky774
 
Join Date: Jun 2010
Location: , OH
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by TimJohansen View Post
Hello!
I am having a hard time finding fuel proof Dope (I believe Pactra is no more) ..
Sig is backordered...
are there any alternatives?
Thank you👍
Tim, I gotta tell you to STAY AWAY from Sig paint. I waited weeks while it was backordered, then finally it arrived. I sprayed it over Koverall that was doped with Sig nitrate. I did everything properly including using Sig thinner which is very $$. So the bottom line is that 10% glow fuel cuts right through the cured paint. Comes off in gobs on the rag. Am I pissed off? Yes.
Old 06-04-2020, 03:04 PM
  #16  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

I will attempt the impossible and try to explain paint without writing a book on the subject.

Basically there are 2 kinds of paint out there, ENAMEL and LACQUER. What are the differences and do you know which one you're getting?

To put it in the simplest terms, ENAMEL turns from soup to solid in TWO WAYS, evaporation of solvents AND a chemical reaction. The first part of the paint drying is the evaporation of solvents, but there is a lot more that has to happen within the paint before it is fully "cured" or hardened. After the solvets have evaprated, depending on the paint composition, the chemical structure undergoes a change by a variety of means which could be exposure to ultraviolet, exposure to oxygen, evaporation of a barrier chemical that prevents other components of the paint to cross link and harden in the can, exposure to heat and finally with paints that are formulated to do so, the addition of a catalyst or hardener. The hardening process can take as little as a few hours (typically paints that use a hardener such as epoxy or urethanes) to as long as months and sometimes even longer. Rustoleum is typical of an enamel that can take months to cure.

Once an enamel paint is cured, its chemistry has been changed which means it can no longer be dissolved by the solvents that you might have used to thin it down initially. This does not mean that the hard paint can not be attacked by solvents, but it does mean that the paint will not return to a liquid state. Maybe some kind of glop, but not liquid paint any more! Got that???

Now we come to LACQUER.
Lacquer does NOT change chemically when it dries. If you were to apply thinner to thoroughly dried lacquer, it would go right back to being liquid paint.

Now that you have a basic understanding about the differences, let's say you painted something with enamel (and we'll call it Rustoleum) and it's dry to the touch. You happen to smear it with some raw glow fuel and eventually you find the paint getting gummy and the color is wiping off. That's enamel that isn't fully cured! Remember, it could take months or longer to fully cure. Now let's say that a plane that was painted with Rustoleum sat around for years and suddenly you expose it to some glow fuel or some harsh solvent. I can promise you it will not get gummy, at least not without the added feature of the paint wrinkling up on the surface as if paint remover had been applied to it.

From my own observations, I find that although fully cured enamels generally have better chemical resistance than lacquers, lacquer has a tendency to dry faster and develop initial chemical resistance in a much shorter period of drying time.

Hopefully this has helped to clarify more than confuse, but I expect you get a little of both.
The following users liked this post:
TimJohansen (06-09-2020)
Old 06-04-2020, 04:27 PM
  #17  
sky774
 
Join Date: Jun 2010
Location: , OH
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
Default

Interesting. My Sig fuel proof paint is disappointing me. I painted the red and black colors a couple weeks ago and they will wipe off some with glow fuel. The red is worse. The white, however, seems quite fuel proof. Any ideas about this?

Would a Sig clear coat maybe help? Thanks
Old 06-04-2020, 05:45 PM
  #18  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

Originally Posted by sky774 View Post
Interesting. My Sig fuel proof paint is disappointing me. I painted the red and black colors a couple weeks ago and they will wipe off some with glow fuel. The red is worse. The white, however, seems quite fuel proof. Any ideas about this?

Would a Sig clear coat maybe help? Thanks
Paint is a deceptively complex subject, but it helps to at least know some of the basics. One of the complexities or problems with paint is that there is no standardization in the industry, particularly in the consumer market. Paints of the same brand can vary chemically color to color and sometimes they have to for technical reasons.

As far as Sig goes, there is no way of telling what the paint is by their description. Undoubtedly Sig is not in the business of manufacturing paint products. They get it from other sources who make it, package it and label it for them. They may even get it from multiple sources which could account for inconsistencies in chemical resistance. As such, getting a paint product from Sig is a shot in the dark. It might be great or it might be awful or anything in between.

The first thing I can recommend with the paint that's already on the plane is to expose it to sunlight for as long as you can if it's possible for you to do so. Leaving the plane locked up in a car that's baking in the sun is another option. Heat and ultraviolet help to speed the curing process and a full cure may be all that you need to make the paint fuelproof. I would make sure to keep an eye on the paint for the first hour of exposure to sunlight and/or heat to make sure there isn't any reaction like bubbling or blistering. If there is, the process needs to be done more gradually. I am confident if you did this and nothing more, the paint would end up being much more fuel proof.

As far as Sig clear, it's hard for me to speculate on the results except that the finish will likely end up more shiny. In any case, exposure to heat and sunlight will speed the cure of the paint.

The only clear that I can recommend as being truly fuelproof is automotive urethane. (2K) which means there's hardener to be added.

An unfortunate fact happens to be that the more fuelproof a paint is, the higher the price and automotive paints (not the touch up spray cans) are anything but cheap. Still, take some of that fuel that's softening the paint on your plane and apply that fuel to the paint on your car and watch as it ignores it like it's rain water.
Old 06-04-2020, 06:11 PM
  #19  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

It comes to mind that I should mention something about paints that could save someone from a huge headache.
NEVER APPLY LACQUER OVER ENAMEL PAINT!!!
Lacquer is a chemically "hot" paint and most partially cured enamels will not tolerate it. The end result could easily look like you've just applied a coat of paint remover to your paint job. Be careful in this respect!
Old 06-05-2020, 11:33 AM
  #20  
Outrider6
Senior Member
My Feedback: (2)
 
Join Date: Apr 2020
Location: Metro Atlanta GA, USA
Posts: 104
Likes: 0
Received 7 Likes on 7 Posts
Default

I am dealing with this issue too now, as I am building a SIG Cub. Sky blue fuelproof paint seems to be impossible to find, but at least I found a fairly fuel-resistant white paint in Rustoleum Appliance Epoxy spray. "Epoxy" is a marketing lie, as it isn't really epoxy at all (probably just a tough enamel), but it held up ok in my sample test. Rubbing some fuel on it didn't seem to dissolve it, but when I let some fresh fuel soak on it, the paint peeled off some. What I did was spray inside a plastic margarine type container. I know I didn't get a really good paint bond to the material, so that is part of the peeling problem. But the good news is that the fuel didn't seem to actually dissolve the paint.
Old 06-05-2020, 12:22 PM
  #21  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

Originally Posted by Outrider6 View Post
I am dealing with this issue too now, as I am building a SIG Cub. Sky blue fuelproof paint seems to be impossible to find, but at least I found a fairly fuel-resistant white paint in Rustoleum Appliance Epoxy spray. "Epoxy" is a marketing lie, as it isn't really epoxy at all (probably just a tough enamel), but it held up ok in my sample test. Rubbing some fuel on it didn't seem to dissolve it, but when I let some fresh fuel soak on it, the paint peeled off some. What I did was spray inside a plastic margarine type container. I know I didn't get a really good paint bond to the material, so that is part of the peeling problem. But the good news is that the fuel didn't seem to actually dissolve the paint.
The "epoxy" in this case is a somewhat modified version of what is known to be real epoxy paint. Just like epoxy glue, if you were to mix both components and put them in a spray can, they would harden or at least turn into a useless glob, BUT to get around this problem, what the manufacturers did was to add a chemical to the paint that would evaporate during the drying process, but while it is contained in the paint it would serve as a barrier between part A and B to prevent there being a chemical reaction and cause hardening in the can.
Normal epoxy paint (where you have to combine ingredients before using) is not reliant on the evaporation of an inhibitor chemical and as such will harden in a predetermined amount of time without the need to breathe or dry. Since drying is essential to this type of one step epoxy, the hardening process can be somewhat prolonged, but eventually it gets there.
Old 06-05-2020, 12:44 PM
  #22  
Outrider6
Senior Member
My Feedback: (2)
 
Join Date: Apr 2020
Location: Metro Atlanta GA, USA
Posts: 104
Likes: 0
Received 7 Likes on 7 Posts
Default

^^ Aha. Thanks for enlightening me. Since marketing sometimes exaggerates, fibs and even lies in many ways, I thought that was also the case with this type paint.
Old 06-05-2020, 03:49 PM
  #23  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

Originally Posted by Outrider6 View Post
What I did was spray inside a plastic margarine type container. I know I didn't get a really good paint bond to the material, so that is part of the peeling problem. But the good news is that the fuel didn't seem to actually dissolve the paint.
The reason why you didn't get a good paint bond with the plastic of the container is because a number of plastics, polyethylene in particular, can not be painted. Well... that's not exactly correct since you DID paint it, but of course the paint didn't stay.
Without getting into molecular specifics, it would be safe to say that plastics that are somewhat soft are likely to reject paint. This includes polyethylene, nylon, delrin and others.
A down and dirty method to determine if a plastic is likely to reject paint is to scrape the plasic with a jagged object or some very coarse sandpaper. If scraping leaves behind a surface that looks like it has little plastc hairs in it that are difficult to get rid of, that's probably a plastic that won't accept paint.

Fortunately there aren't too many instances in the field of model airplanes where soft plastics are encountered that may need to be painted, but at least one example is nylon hinges. No matter what you do, paint will not stay on them!
Old 06-05-2020, 05:18 PM
  #24  
GoNavy
My Feedback: (15)
 
Join Date: Jan 2002
Location: Rib Lake, WI
Posts: 542
Likes: 0
Received 0 Likes on 0 Posts
Default

If you have good skills using a brush, System Three has polyurethane colored paints. Minimum of three coats. Hot fuel proof when you add the crosslinker. They no longer recommend spray painting except by pressurized means such as AAA, which is out of my league. I have had mixed results trying to brush it on. Others do very well. It is waterborne so almost no stink.
Two part epoxies are available if you can spray paint.
I am on the look out for polyurethane colored paints that are free from isocyanates, which are nasty. The new technology has made its way in automotive refinishing and other uses. If anyone has found an isocyanate free polyurethane or acrylic that is fuel proof and practical, please let me know.
Old 06-05-2020, 06:25 PM
  #25  
airsteve172
 
Join Date: Jun 2005
Location: , NY
Posts: 257
Likes: 0
Received 10 Likes on 10 Posts
Default

Originally Posted by GoNavy View Post
If you have good skills using a brush, System Three has polyurethane colored paints. Minimum of three coats. Hot fuel proof when you add the crosslinker. They no longer recommend spray painting except by pressurized means such as AAA, which is out of my league. I have had mixed results trying to brush it on. Others do very well. It is waterborne so almost no stink.
Two part epoxies are available if you can spray paint.
I am on the look out for polyurethane colored paints that are free from isocyanates, which are nasty. The new technology has made its way in automotive refinishing and other uses. If anyone has found an isocyanate free polyurethane or acrylic that is fuel proof and practical, please let me know.
I found your mention of isocyanates to be very ironic in my case.
I've owned and operated an auto body shop for many years and I'm currently involved with furniture restoration where I use many of the same materials and finishes as in auto body. In all the years that I've sprayed paints with exotic chemistry, I hardly ever used a respirator, I enjoy smoking and I've never suffered any ill effects as a result! (Save your admonitions)
Now the irony. I was at the airport last weekend to paint a utility locker that sits behind the airplane at its parking spot. The paint was Rustoleum that was applied with a roller outdoors. I absolutely hated the smell of the stuff and ended up going home with a headache!
I'll stick with the urethanes and the isocyanates. They work much better, usually smell much nicer and they don't give me a headache! LOL

I might also mention that no flowers ever smelled sweeter to me than the aroma of jet exhaust drifting across the airport. Most people don't get it, but pilots do!

Last edited by airsteve172; 06-05-2020 at 06:42 PM.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.