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Coating or sloshing compounds to resist ethanol degradation of fiberglass aircraft fuel tanks using automotive fuel.

Posted By:
Al Todd
Young Eagles Pilot or VolunteerHomebuilder or Craftsman
#1 Posted: 8/18/2009 21:15:19

The June 2009 EAA Sport Pilot magazine on page 28 shows a photo of the Urban Air Samba with the legend stating that "composite fuel tanks have been specially treated to allow fuel containing up to 30% ethanol." 


I have tried to contact the company to see if any information about such a compound might be available.  I also asked if the company would consider selling the material.  After three weeks I have not received a reply.


I have also spent considerable time on the web searching for any company that could offer such a material.  So far I have found only one, a division of PPG.  The major problem with that compound is that it is used on the space shuttle, and costs about $600 per pint.  Since my homebuilt's budget is slightly less than NASA, I had to decline their offer.  Sounds like good material though.


With all the interest in trying to solve this problem it seems EAA could be helpful.   Any ideas? 



David Darnell
#2 Posted: 8/19/2009 11:44:56

    Well,  I'd look into what we used to use for corroded gas tanks on cars. No idea how it would work for fiberglass

If I recall correctly, it was called Red-Kote or Red Coat and it was around $30 a Qt. Might  be something to look into


Dan Horton
#3 Posted: 8/19/2009 16:56:25

Al, I can't comment on sloshing compounds, but I did do some recent research regarding composite resins suitable for ethanol exposure following a TC call from a builder.  As you probably know, underground fuel storage tanks are composite, so the entire gasoline distribution network had to address ethanol.  Visit your favorite resin manufacturer's website or call their technical hotline.  Look for resins that meet UL Standard 1316, the current spec for new fuel storage tanks.  You'll find the reference in the resin's product data sheet.

Dan Horton
Kent Misegades
Young Eagles Pilot or VolunteerHomebuilder or CraftsmanAirVenture Volunteer
#4 Posted: 8/20/2009 08:16:20

Al, I wrote the article.  The source of information was Josef Bostik of Urban Air USA, seller of the Samba and Lambada, http://www.urbanairusa.com/    These planes are manufactured in the Czech Republic.  

One compound that has been cited by some manufacturers is Damon Red-Kote:



3-M also sells a product called Scotch-Clad 776 which is intended for sealing fuel tanks. 

Heed the warnings regarding compatibility with any fuels that might be used with these or any other compounds, and of course contact the manufacturers for final word on whether their compounds are suitable for your needs.

Kent Misegades

EAA 520919, Cary, NC



James Scott
Homebuilder or Craftsman
#5 Posted: 8/20/2009 08:30:05

I got this info from Spencer Aircraft. Supposed to be some that have tried this product with success on homebuilt aircraft in the last month or so.  http://www.caswellplating.com/aids/epoxygas.htm

It looks like something I would use after reading the website.

Jim Scott

EAA 179717

Arlington WA

Brian Vasseur
Homebuilder or Craftsman
#6 Posted: 8/20/2009 19:38:31

I used Randolph 912 sloshing sealer. They state it's not for aircraft use but I used it anyway. About $20/quart which easily did my two 5 gallon tanks. Available from Wicks. Impervious to alcohol and additives.

Charles Smith
Homebuilder or Craftsman
#7 Posted: 8/20/2009 19:49:24

I used Jeffco 9700FCR on my tanks.  Available from Spruce:



No statements there about alcohol fuels but you won't likely find that from any supplier.  Alcohol in fuel is a tricky thing for degrading organic components such as rubber and epoxy.  At 30% it is severe but will get worse as the alcohol content drops to the 15-20% range.  So having a 30% alcohol fuel and adding pure fuel to it could potentially make the chemical environment worse.  Be careful.  The best advise is to avoid alcohol/fuel blends if you can.


Good luck,


Jim Heffelfinger
Homebuilder or Craftsman
#8 Posted: 10/15/2009 22:58:10

Might try this - seems to be okay so far at 10% ethanol.  Easy to work with and not as finicky as the Randolf re any water in the tank.    ( had a number of tanks turn into a loose bladders floating around when there was still a tiny bit of water in the tank. )




Pete Christensen
#9 Posted: 7/17/2010 14:58:49

Do a web search on Kreem.  Kitfox used to use it in their tanks.  Al;so try Kreem Wiesse.  Personally I remove the alcohol from my fuel with water.



Kitfox III