Logo
FULL SITE MENU

Permatex Aviation #3 dissolves with Fuel

K

Klink

Regular Contributor
I read that one should use Permatex Aviation (Form -a-Gasket #3, in the brush can) for sealing the threads on the fuel filter water separator head. I applied it to the male and female threads on a 3/8" stainless steel fuel shutoff valve and 3/8 NPT male x 3/8" barb fitting and followed the instructions, letting it set for 20 minutes (it says a few minutes) then assembled everything tight and it leaks like a sieve. I wondered about the Permatex Aviation #3 as I can clean it off with alcohol and gasoline has alcohol in it. The gasoline came right through the threads.

What gives with that, as all over the internet everyone says to use Permatex Aviation?

I think I'm going to try the yellow Teflon tape, since the valve comes before the fuel filter. I read to use the yellow Teflon tape and not to put any on the first threads. Since it is going before the filter if any Teflon bits get past the threads, the fuel filter will pick it up.

What about this product, it says it is specifically for E10 and E85 fuels:
Gasoila E-Seal.JPG

Premium pipe thread sealant with PTFE. Provides a positive seal on pipe thread, joints, fittings, hoses, nozzles, LPG cylinders, pump assemblies, motors, oil burners, hydraulics, compressors, engines, housings, plugs, fuel lines, couplings and more. Excellent resistance to gasoline, up to 20 percent alcohol and petroleum blends, petroleum solvents, kerosene, diesel oil, propane, butane, LPG, cutting oils, ammonia, aliphatic solvents, acids, steam, potable water, compressed air and more.​
 
Last edited:
Yes you can you the Gasolia but you use Permatex#2 not the #3 to seal threads. I myself use Rectorseal 5 as nothing effects it. You can get it at Home depo and Lowes.

rectorseal-pipe-putty-sealants-25790-64_1000.jpg
 
Thanks fazbullet. Looked up spec sheet on the Rectorseal 5 it is good for everything, in my case aluminum and E10 gasoline. Will go with that.

P.S. - tech sheet said to call them for cure times for gasoline, so I did. They said for a 3/8" pipe 12-24 hours.
 
Found the tech sheet on Permatex Aviation #3 https://441py33rout1ptjxn2lupv31-wpengine.netdna-ssl.com/wp-content/uploads/tech_docs/tds/80018.pdf

among it's uses it says it is for "Close fitting machined surfaces, Threaded connections", that makes sense since it is a thin liquid, like paint. It says Assembly is operational after 4 hours, full cure is effective after 24 hours.

I should have waited 24 hours before putting it to work. Still, I find it too thin, and it softens with alcohol so I will go with Rectorseal.
 
Today I had to take everything apart and clean each fitting, the filter head and filter case with alcohol to get all the Permatex Aviation off. It was melted all over the place and left chips of hardened material in the filter bowl bottom that came from the fittings before the filter and chips that came out from the fittings that are past the filter and got to the bulb when I was pumping all the fuel out. I'll have to flush it at the engine just in case, though I think it did not get that far as I never ran the engine.
 
I put all the connections for the fuel/water separator back on with Rectorseal 5. Very clean to work with versus Permatex 2 or Aviation 3. I'll let it sit till Monday (48+ hours), or the next time I can install the filter back in place. Will report how it turned out. One good thing that came out of all the work is that I'm going to take the opportunity to relocate the filter to a better location and set it up so it is easy to work on and remove.
 
I installed it after 72 hours and no leaks or smell of fuel now. Looks like everything is good to go. Thanks Faztbullet and all.
 
I use nothing but Permatex High Tack. It will not dissolve in gasoline. In fact, I repaired a 1972 Oldsmobile Vista Cruiser gas tank with Permatex High Tack and cotton gauze (it rusted and leaked under the support strap). Drove it for years like that. The nice thing about the Permatex High Tack is that it NEVER hardens completely and can be removed with lacquer thinner and a paper towel - even on exhaust manifold gaskets. I once removed the copper head gasket on a Kawasaki motorcycle and used only Permatex High Tack and it worked fine.
 
Back
Top