Need help soldering (not electical)

[81xsproject]

The picture below (currently a HUGE pain in my side as it has kept me from making my first test run on FI for 2 days now) is of a threaded brass elbow I absolutely cannot get to seal in the aluminum fuel rail for the life of me. I have used fuel tape and tapped it, and tried everything but epoxy (which is the absolute last resort due to its permanent nature). Last night I had the great idea to solder it. It would seal it, hold up to the pressure (38-45 psi), and be removable with heat. I got it all put back together for like the millionth time and it leaked. Other than electrical, I don't have much experience soldering. Some proper procedure, equipment, and material recommendations would rock.
thanXS in advance.

.

[Montreux_Blue]

I have only "brazed" copper pipe a couple times so I'm not sure if it would be the same for brass and aluminum your bonding it to. Not sure about how to do a threaded piece but when you do copper you have to lightly sand both connections that need to be sealed then add flux to both parts, put it together, heat the piece and then apply the solder at the top and let it run around the connection. Hopefully that helped you some.

[Montreux_Blue]

Have you tried Loctite thread locker?

[81xsproject]

I haven't. I would be surprised if it worked and the gas didn't work through. The elbow only lightly threads in. I was very surprised that the yellow fuel tape didn't work.

[Montreux_Blue]

Wasn't sure is they made a Loctite that was fuel resistant. My guess is that epoxy would be your next step then. So just ask yourself first do you really need to remove that elbow for any reason, I can't think of one.

[crazy steve]

Regular solder won't bond to aluminum... so try this guy:

www.muggyweld.com

He sells a 'solder' that will bond almost any metal to any other and it melts at only 350 degrees. Not something you would want to use for a structural piece, but should work for this.

'78E original owner

[tbishop11]

I hope it works that looks amazing!

[Crazcnuk]

I assume that is an NPT fitting (the brass)?

If it is go to your local hydraulic supply house and look at an ORB brass elbow.

The ORB ones are threaded with normal (not NPT interference) thread and have a washer and o-ring to seal.

You can get ORB to NPT 90deg adaptors too, or prety much whatever you need.

[fredintoon]

- - a threaded brass elbow I absolutely cannot get to seal in the aluminum fuel rail for the life of me. - - - Last night I had the great idea to solder it. It would seal it, hold up to the pressure (38-45 psi), and be removable with heat. I got it all put back together for like the millionth time and it leaked. Other than electrical, I don't have much experience soldering. Some proper procedure, equipment, and material recommendations would rock.

Hi 81,
Even if the muggyweld does work it'll be just as permanent as epoxy, right?
I'd say the first thing is to find out exactly which thread is in the fuel rail.
If rail & fitting are both tapered pipe thread, teflon pipe tape and reefing it tight will work to make a seal.
But, to expand on what Crazcnuk sez, if the rail is tapped with a parallel pipe thread, no way will a tapered-thread fitting seal into it.
So, yeah, take the rail to a hydraulic fittings store and ask them what will seal into this?

[Silent]

I work with the manufacture circuit boards, and you're not going to be able to solder aluminum and brass. The brass will take the tin/lead just fine with nothing more than a cleaning and flux, but the Aluminum will not. The only way to get Aluminum to solder properly is to Zincate it, nickle strike, then copper plate it. The solder will then stick to the copper, which is stuck to the nickle, that is stuck to the aluminum. It should hold fuel, but I can't say for sure. Plating aluminum properly is about one of the harder things to do properly.

Sorry, can't help on the "fix-it" side other than to ask if you used pipe tap to tap the hole in the aluminum and a matching pipe thread on the fitting. Since pipe threads are tapered, you shouldn't need any sealant.

[rpgoerlich]

What kind of fitting was on it before ?

[81xsproject]

It had a brass or copper block-off plug that I drilled out (which I am sort of kicking myself in the @ss for now). I checked out the muggyweld and it looks good except for the 10 days to the door. I guess I will try the fuel tape again and it that doesn't work, I will have to decide between the fuel tank epoxy and waiting on Muggyweld Super Allow 1.

[oseaghdha]

The fuel rail is probably NPSF, which is straight thread.

[rpgoerlich]

Was thinking you might be able tap it and use a banjo bolt, fitting & crush washers if you could find one that size and still have the flow you need.

[BigDick]

Or what you might do is score the end of your fuel rail so it'll hold the epoxy good and tight, then coat a bolt or longer fitting with wax, or bar soap (so it will release) then use epoxy around that to make your new threads. Since you're forming to the bolt/fitting it shouldn't be too difficult to seal this. Not exactly the best way to do this but it's an option.