J

Juan Pablo

Member
Hello again from Argentina. My RV-8 QB have some fuel leaks through the T-708 tank cover access plate, and through the mounting plate for the fuel sender in T-708. It could be a problem with the gaskets? I put 2 mm cork gaskets in both places . Any suggestions or comments are welcome, thank you.
 
Very common Juan - if you're using cork gaskets! Many of us don't use the gaskets at all - just pro-seal the sender to the cover, and the cover to the tank. remember to pro-seal the screws before they go in as well. Leaks gone!

Paul
 
Permatex hi-tack or aviation form-a-gasket

I used the cork gaskets on the tank covers, and the rubber gaskets on the fuel senders. In both cases, I used Permatex Aviation Form-a-gasket which is a brown, sticky sealant that sort of partially hardens. I coat both sides of the gasket liberally, as well as the screws. There is a very similar material called Permatex High-tack. It is slightly different, but I have had equally good success with that in the past.

I have always had good success with it on autos; it is fully resistant to oil, fuel, ethanol. It is much easier to remove in the future than Pro Seal would be. And it doesn't leak. Personally, I think this is the best way to do it.
YMMV
 
Thank you to all of you, yours answers are very useful to me..one more question, where can I get this products (pro seal or similar)? by internet?
thank you again!!
 
Aircraft Spruce...

Juan Pablo said:
Thank you to all of you, yours answers are very useful to me..one more question, where can I get this products (pro seal or similar)? by internet?
thank you again!!
Click to expand...

...has it, Juan:

http://www.aircraftspruce.com/search/search.php?query=proseal&searchsubmit=Search&search=1

It mixes 10:1 sealant to hardener and you have a long time to work it. Try to find a scale of some sort (postage scale) and mix it 10:1 by weight. Proseal is used by certificated and Military aircraft and is fuel, oil and Jet-A resistant and never hardens. Smells lousy but it's the good stuff,

Best,
 
Last edited:
We tried it...without the cork.

scsmith said:
I used the cork gaskets on the tank covers, and the rubber gaskets on the fuel senders. In both cases, I used Permatex Aviation Form-a-gasket which is a brown, sticky sealant that sort of partially hardens. I coat both sides of the gasket liberally, as well as the screws. There is a very similar material called Permatex High-tack. It is slightly different, but I have had equally good success with that in the past.

I have always had good success with it on autos; it is fully resistant to oil, fuel, ethanol. It is much easier to remove in the future than Pro Seal would be. And it doesn't leak. Personally, I think this is the best way to do it.
YMMV
Click to expand...

I read all kinds of threads, and most... as paul does, suggest proseal. The weekend was upon us and I didn't have any proseal that wasn't expired. So we went to O'Reillys and bought some of the Permatex Aviation Form a Seal. We removed the cork and cleaned the plate and surface of the tank with MEK.
This stuff comes with a brush, so we painted it on with the brush on both the plate and the tank. We did this without the cork seal. We were attempting to put the parts together as others have done with proseal... metal to metal. The instructions say to wait until a few minutes for it to become tacky... which we did. We then installed the plate and put the screws in. We waited 30 hours for it to dry. The instructions say that you can put, whatever it is that you are working on back into service after 24 hours. We put the fuel back into the repaired tanks 30 hours after we put the parts back together. We came back after another 24 hours to discover fuel was leaking from the bottom of the plate. Just to be clear, it was NOT leaking thru the screws. Drag.... so we removed the fuel and the tank again. We again cleaned all the stuff off the surface. By now we have moved into the regular work week and were able to purchase proseal. In a nutshell, the proseal worked and the permatex stuff didn't. We had some time on our hands and we didn't mind trying something that was common and "off the self". But I know that this sort of thing can be very frustrating for builders in general. This is especially true when you are anxious to go fly and have some fun. Your mileage may vary and maybe this stuff worked for you. But it didn't for us. Good luck.
 
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