Fuel Tank Return Fitting Addition

[Ed.Meyer]

I want to add a fitting to our Patrol fuel tanks for fuel return lines. We are planning on using Electronic Fuel Injection which will need it. I bought these ALUMINUM WELDING FLANGE AN867-2 to be welded on. I am thinking that using some of the low temp aluminum welding rod I have should work very well. The stuff melts at a little over 700 degrees and flows very nicely if parts are nice and clean with a stainless steel brush. And, it seems to be plenty strong. Does anyone know of any reason this would not be a good idea?

[alaskabearhawk]

If you are talking about the "magic" welding rod you find at the state fair, etc, it's not an approved aircraft manufacture/repair method. I certainly wouldn't use it on a critical component such as a fuel system. If you have any questions, call Kent White at TM Technologies. He will give you the straight scoop on that stuff.

[Mark Goldberg]

You know Ed, if the aluminum welding becomes too difficult you might get away with using ProSeal to attach the wlding flange. I used it on my RV8 fuel tanks, and never had a leak. It would seem positioning this high on the tank might reduce problems if it ever did start to leak. Mark

[Ed.Meyer]

Thanks. I looked up the TM Technologies web site and lots of info there. Mark, what alloy are the tanks made with?

[Mark Goldberg]

5052H32 in .050

[fly_n_low]

.050 5052 is easy stuff to TIG. You'll regret any shortcuts later on...

[Ed.Meyer]

Thanks. I found someone that successfully welded up his own 5052 tanks and can do ours. He uses TIG.

[haribole]

Hi Ed

I am in the same boat, looking to get a flange welded in the tank for the return line. Which part of the tank did you choose to get this welded and how did you route the fuel lines through the wing. Just looking for some ideas.

Thanks
Hari

[jaredyates]

I have a dumb question. Couldn't a return line just be teed into any of the feed lines upstream of the pump? There must be some reason that wouldn't work that I can't think of. It would save you the welding plus a while lot of plumbing.

[John Rheney]

Would risk returning air back into the supply line?

[Matt K.]

If welding isn't an easy option, could use va-112 flanges from vans with ad-41h or ad-42h closed end pop rivets and pro-seal. Check grip length on those rivets vs tank thickness, I don't remember. Depending on the injection system the return can go to a fuel line upstream of the selector for a purge only system like airflow performance (must select opposite tank from the return when purge is open). Efii and Continental continuous flow type systems would need to return to the tank through a duplexing fuel valve. That valve isn't going to fit in our floorspace without building up a box. -Matt

[Ed.Meyer]

The reason I need the returns to the tank is EFII, continuous flow, requires it due to air bubbles and heat dissipation. I have not yet had the flanges welded on but I am planning to put them at an easy location, probably about centered on the end of the tank, that is easy to get at and plumb through the big lightening holes in the ribs. I am planning on running the return line along side of the front feed line on each side. I already have the duplex valve needed but haven't figured out how to install it yet.

[Greg_Marlow]

I don't think you need to install the duplex valve. You could just pick one tank or the other to return the fuel to. As long as you have an equalizing line between tanks so you don't overfill the return tank. Just run the return line directly from the engine into one tank.