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Author Topic: Fuel Proofing  (Read 1482 times)

Offline t michael jennings

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Fuel Proofing
« on: November 01, 2008, 03:46:03 PM »
Gentlemen,

What is the best way to fuel proof the engine/fuel tank area?

       Butyrate Dope

       Epoxy Glue

       other

t michael jennings
knoxville, tn





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Offline Jim Oliver

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Re: Fuel Proofing
« Reply #1 on: November 01, 2008, 07:51:14 PM »
Epoxy finishing resin or thinned epoxy is probably the most fuel proof.

You will get different views on thinning epoxy---some folks use acetone or 91% rubbing alcohol or denatured alcohol.  I use acetone---it only takes a very little to get the epoxy thin enough to paint.  A "little" heating of the epoxy before mixing will make it thinner-----also will probably make it set faster, too.

Paint it on with a fairly stiff brush; one of the throw-a-way brushes works OK.  Being cheap, I clean mine and reuse them............

Just remember,epoxy is HEAVY.

Jim
« Last Edit: January 28, 2009, 10:37:04 AM by Jim Oliver »
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Offline Ralph Wenzel (d)

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Re: Fuel Proofing
« Reply #2 on: November 04, 2008, 10:28:22 AM »
Disclaimer:  I have not tried it yet, but will on a couple of planes, "real soon now". One good coat is adequate. (I'll probably use two thin coats, just to be sure . . .)

Doug Moon uses and recommends Zinsser 1-2-3 Bullseye Indoor/Outdoor Primer. It's white, so you can see where you've painted. About $8/qt.
(Too many irons; not enough fire)

Ralph Wenzel
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Offline Pinecone

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Re: Fuel Proofing
« Reply #3 on: January 28, 2009, 07:12:07 AM »
I use WEST System epoxy.  Using the Slow Hardener.  Then paint on the epoxy then hit it with tha covering heat gun.  This heat thins the epoxy so it soaks in, and also expands the pores of the wood to help the epoxy soak in.

You can then blot with a paper towel to remove excess epoxy.
Terry Carraway
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Offline FLOYD CARTER

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Re: Fuel Proofing
« Reply #4 on: February 02, 2009, 03:48:53 PM »
I keep it simple and use multiple coats of Brodak clear.  My tanks don't leak and I seal the fuel line holes with silicone goo.

If you have a burst tank, chances are your plane will be soaked right to the tailwheel anyway, where there's no epoxy or anything.

Floyd
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 Staying old is hard"
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Offline Jim Kraft

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Re: Fuel Proofing
« Reply #5 on: February 02, 2009, 06:00:54 PM »
I used to use epoxy, but there were two problems. 1. It always seemed to turn a brown color and absorb the fuel or oil. 2. I could not get dope to stick to it unless I somehow sanded it to get the wax off. I have been using clear dope for some years with much better success. I know many use epoxy just fine, but just does not work for me.
Jim Kraft

Offline billbyles

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Re: Fuel Proofing
« Reply #6 on: February 06, 2009, 11:29:37 PM »
I brush on three or four coats of Sig clear Lite Coat dope followed by two brush coats of two-part (catalyzed) polyurethane light gray (I use Sikkens polyurethane catalyzed but unthinned for brushing).  Also the same treatment for the inside of the cowl.  Totally fuel proof, not just fuel resistant (and I use up to 20% nitro at times.)  Never changes color, always looks clean when the cowl is removed.
Bill Byles
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Offline BillP

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Re: Fuel Proofing
« Reply #7 on: February 08, 2009, 03:23:30 PM »
Since the early 1990s I've coated engine and tank compartments with thin ca and dope over it. Before that I thinned Duco cement with acetone and brushed on several flood coats...then dope over it. People tell me these will break down under nitro but they haven't. I've had (and still have) 10-15 yr old planes with many flights that show no saturation with either method. I mostly fly with 5% nitro so that may be why they do ok. If it really bothers you nothing is more resistant than epoxy. I've used it too but don't anymore because it's more hassle than the others. Hanging planes nose down helps too...mine are stored nose up btw.


bp
Bill P.

Offline Pinecone

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Re: Fuel Proofing
« Reply #8 on: February 09, 2009, 10:18:20 PM »
Epoxies don't have wax in them.  But they can develop an amine blush during curing.  That needs to be removed before recoating.  It is water soluble, so scrubbing with a sponge and water will remove it.  You can also lay on a layer of peel ply and when removed after curing, will leave a clean roughened surface.  Also an epoxy surface is very hard and can be very smooth, so dope or other products will not stick.  Sanding allows a mechanical grip.

Finishing polyester resins do have a wax.  Polyester resins will not fully cure in the presence of air (or the moisture in teh air, I forget which).  So the finishing resin has a wax that floats to the surface and seals the air out, allowing a full cure.  Laminating ployester resins do not have the wax and will have a tacky surface after curing.
Terry Carraway
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Offline Shorts,David

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Re: Fuel Proofing
« Reply #9 on: January 06, 2021, 02:07:12 PM »
Old thread, maybe some newer methods. How fuel proof is a urethane or polyurethane or varathane spray? Seems like it might be lighter than epoxy. How is the weight of CA compared to epoxy. I'm actually building weight conscious this time. Imagine that.

Offline Dan McEntee

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Re: Fuel Proofing
« Reply #10 on: January 06, 2021, 04:30:35 PM »
Old thread, maybe some newer methods. How fuel proof is a urethane or polyurethane or varathane spray? Seems like it might be lighter than epoxy. How is the weight of CA compared to epoxy. I'm actually building weight conscious this time. Imagine that.

    If you use epoxy, you are supposed to thin it anyway, even the finishing resin kind. One or two coats weighs almost nothing. After trhat, I just make sure any gaps or cracks are filled.
  Type at you later,
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Online Howard Rush

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Re: Fuel Proofing
« Reply #11 on: January 06, 2021, 08:20:59 PM »
The brush-on Varathane I used 30 years ago was completely fuel proof.  I still have some, but I canít get the lids off.   I couldnít find any new Varathane the last time I looked at the hardware store.
The Jive Combat Team
Making combat and stunt great again

Offline Dave Hull

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Re: Fuel Proofing
« Reply #12 on: January 08, 2021, 08:36:27 PM »
I tried the spray can Varathane maybe 8 or 10 years ago when refinishing props. It did not stand up to fuel. It got gummy....

Dave

Offline Shorts,David

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Re: Fuel Proofing
« Reply #13 on: January 09, 2021, 10:55:35 AM »
OKay, I went with an epoxy resin thinned with some lacquer thinner. It definitely looks superior to the clear dope I've used on everything else.


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