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Building Tips and technical articles. => Paint and finishing => Topic started by: John Rist on December 14, 2011, 09:25:06 AM

Title: Fuel Proofing Latex
Post by: John Rist on December 14, 2011, 09:25:06 AM
What is the best way to fuel proof Latex?  Military flat ---

 ???   #^
Title: Re: Fuel Proofing Latex
Post by: john e. holliday on December 14, 2011, 10:09:10 AM
Two part auto motive clear.    Of course have you tried a scrap peice with clear dope? H^^
Title: Re: Fuel Proofing Latex
Post by: John Rist on December 14, 2011, 10:33:54 AM
Two part auto motive clear.    Of course have you tried a scrap peice with clear dope? H^^

Turns out clear dope eats Latex.

Any particular type of Automotive clear?  Do I get it at a local paint shop?

 #^
Title: Re: Fuel Proofing Latex
Post by: John Miller on December 14, 2011, 11:58:11 AM
I thought Latex paint was fuel proof. Am I wrong?  ~^
Title: Re: Fuel Proofing Latex
Post by: Tim Wescott on December 14, 2011, 12:23:14 PM
I've got a pdf of a Model Airplane News article on painting with latex by Roy Vaillancourt, in which he says: "If, however, you are using a glow engine, you’ll need to protect the finish with a clear epoxy or polyurethane top coat after it has dried fully."

I'd probably use System 3 urethane clear, which can be had either from System 3 or from Nelson's Hobby.  The stuff is enormously expensive, but it looks like you don't need much of it.  There's also automotive urethanes, which, incidentally, are also enormously expensive.  Sigh.

Note that the System 3 stuff is only fuel proof if you use the cross-linker.  If you air dry it then it's not guaranteed.
Title: Re: Fuel Proofing Latex
Post by: Steve Helmick on December 14, 2011, 01:00:04 PM
Regular polyurethane varnish is not supposed to be compatible with latex. I did some research after my rocket scientist brother put polyurethane varnish on an oak toilet seat. It never completely hardened, so my guess is that it was finished with a latex stain. I don't know if he trashed it, or removed the finish and started over, but I know he was not happy about it!  LL~ Steve
Title: Re: Fuel Proofing Latex
Post by: Russell Shaffer on December 14, 2011, 06:50:15 PM
I have used oil based poly over latex sucessfully, but I have concerns about adhesion.  Sometimes poly will peel off if everything isn't right. I painted some profile canopies with latex and they disolved, so I don't do that anymore. Has anyone tried the Duplicolor wheel coating?  It is supposed to be really great according to the label.
Title: Re: Fuel Proofing Latex
Post by: Tim Wescott on December 14, 2011, 10:14:20 PM
I have heard that the Duplicolor wheel clear coat is fuel proof, but I haven't tried it.

I strongly suspect that it is lacquer, in which case it'll cause about the same problems as dope.  But -- I dunno.
Title: Re: Fuel Proofing Latex
Post by: louie klein on December 15, 2011, 06:17:52 AM
I just stick with a 100% dope process. If you have to mix any kind of chemicals I would stick with the old school tried and true method and hone your finishing skills. IMO---LOUIE  H^^  D>K
Title: Re: Fuel Proofing Latex
Post by: John Rist on December 15, 2011, 08:00:37 AM
I just stick with a 100% dope process. If you have to mix any kind of chemicals I would stick with the old school tried and true method and hone your finishing skills. IMO---LOUIE  H^^  D>K
You are probbly correct.  The only advantage of Latex house paint is custome mix colors.  Scale needs color matching and dope color selection is getting less and less.

 HB~>
Title: Re: Fuel Proofing Latex
Post by: Tim Wescott on December 15, 2011, 08:06:51 AM
You are probbly correct.  The only advantage of Latex house paint is custome mix colors.  Scale needs color matching and dope color selection is getting less and less.
http://stunthanger.com/smf/index.php?topic=20232.0

Although you'll probably still pay less for latex paint and overcoat, you can (apparently -- I haven't tried this) get your custom colors for dope.
Title: Re: Fuel Proofing Latex
Post by: john e. holliday on December 15, 2011, 09:14:20 AM
PPG Paints is where I get my automotive clear paints.   Yes it seems expensive, but it takes very little to get a shiny coat.   I think I use about 6 ounces on my P-39. H^^
Title: Re: Fuel Proofing Latex
Post by: billbyles on December 15, 2011, 11:23:47 PM
You are probbly correct.  The only advantage of Latex house paint is custome mix colors.  Scale needs color matching and dope color selection is getting less and less.

 HB~>

"...dope color selection is getting less and less."

???  Have you looked at the standard color chart for Randolph butyrate dopes?  The color chart is available for free from Aircraft Spruce & Specialty as well as one of their catalogs (which is nearly two inches thick).  The catalog shows even more colors as the Randolph color chip chart.  The prices for Randolph dope is really reasonable compared to the current model dopes available & Aircraft Spruce ships quickly.

Title: Re: Fuel Proofing Latex
Post by: kenneth cook on December 16, 2011, 03:14:10 PM
           Nelson hobby paint is back in business with a new owner. With the required crosslinker, it is nitro proof up to 40%. The clear as is is good up to 10%. John Diselits I believe is the new owner. You can purchase the clear. This paint works terrifically for latex paints. Ken