How do I add a methanol compatible, leak proof fuel return hose barb or AN type connection to "plastic" gas tank?

I cannot find a fuel valve specifically for non-metal gas tanks. I've found ones that have a pipe thread for metal gas tanks. But I'm not sure if there is a way to seal a metal fitting such as this to a "plastic" tank? Most adhesives or epoxys will not bond to the type of material used for "plastic" gas tanks?

I assume you cannot tap a hole with the appropriate threads in a "plastic" gas tank? Wouldn't the threads strip too easily? Besides, I would need some type of sealant to seal the threads from leaking.

I guess the cleanest method would be to find a fuel valve that has an o-ring for a seal and a couple screws that thread into holes that are partially drilled into the tank. Maybe there is some type of threaded cylindical metal piece that can be hammered into the hole for accepting the screws?

Right now I have a small hole in the tank with a grommet that keeps it from leaking. The grommet/hole accepts a barb on a fuel pressure regulator. I cannot find the right size grommet needed for my application. My existing grommet is torn.

Any ideas?

 

Any ideas yet?

 

Check with JEGS or SUMMIT RACING for fuel line / fuel cell manufacturers for drag cars (they use small plastic fuel tanks in the trunk). Call those manufacturers....they should have exactly whay you are looking for.

Oh yea..EARLSmakes a lotta fuel line stuff...they may be able to help.

 

Scooby

While I was in college, I installed fire sprinklers in homes for money. The sprinklers are made of brass and we often times used sprinkler head adaptors that had plastic threads. I only used four wraps of teflon tape when I put the heads in. To test for the fire dept. I had to pump up the system to 150+ pounds for at least 24 hours.

The reason I tell you this is that it is possible to buy a NPT tap that will match up to the fuel valve you found for metal tanks with pipe threads. When you drill the hole go slow and be careful when you tap. I am not entirely sure what type of sealant you would use on the threads that will stand up to fuel. I automatically think to use pipe dope, but don't know what happens when fuel mixes with dope. Good luck man and let us know what you come up with.

 

I would think that pipe threads screwed into plastic would be self sealing. Teflon tape should not be affected by gas and would not hurt. You might not even need to tap the hole first. The pipe threads would just press into the plastic. If this is a return line, I would put it as high as possible on the tank.

 

I would think that the plastic wall of your "gas" tank would be too thin to take threads. What you need is a bulkhead fitting. It's like a hollow bolt with internal pipe threads that clamps to the wall after insertion by tightening the "nut". Then you screw in whatever type fitting you want.
WeatherHead makes these - as do other manufacturers. Use teflon tape to seal. The fitting head & nut should have rubber type washers to seal when they clamp.It may be tight fit thru the filler hole of your tank to hold the fitting from turning so you may need needle nose vise grips or similar.
Good Luck.............