On a 1954 Hudson Hornet I recently bought, I found a small gas leak at the joint where the neck is soldered on the tank. Since I was also getting a clogged fuel filter, it was time to tackle the gas tank. So she was cleaned out of all sorts of crap then de-rusted & sprayed down with WD40 to protect from flash rust. Then I drained all the remaining WD40 from the tank & let her sit in the sun for a couple days to further dry. There is no concern of explosion and I even put my lit torch into the tank to make sure, so let’s focus on my real question now that we know I’m safe. My question: What’s the best way to solder this up without melting all the other solder currently in place? Specifically what tools & products would you use? I’ve Soldered a lot of copper pipes over the last 25 years but this is foreign to me. Sent from my iPhone using H.A.M.B.
Wow, that tank looks clean inside! I had a filler neck removed and relocated to the center of a tank. I took it to a local radiator shop. He soldered a patch on the original hole, cut a new one and soldered in my filler neck. Cost me $60 here in the expensive SF Bay Area. Yours looks like it just needs some touching up. I would check your local rad shop first. It'll probably cost you a six pack and then you won't have to worry about it!
I'd use a high wattage electric soldering iron or maybe even break out the big tinners irons. I heat the tinners with a propane fired weed burner, a distance away from the gas tank. Use Harris tinning, soft soldering flux and acid core solder, which you can purchase at a welding supply usually. Using a soldering iron reduces the probability of a sudden ignition and allows you to put the heat where you want it. You might even get away with 'reflowing' the existing solder.
MELTING the solder...is the only PROPER way of verifying a PROPER solder joint. Don't understand your concern, just do it as you apparently know ow to. I've done the same thing and more (big patch) to a couple of my own (two used, and one new) gas tanks. All three work fine, not a problem. I've even had to use solder to fill several pin holes in one welded tank. A big..."U" shaped hole in my tank to make room for the gear end of a Quick Change rear end. It had five or six pinholes that needed sealing. Soldering did the trick. Mike
I was going to suggest using one of those "tinner" soldering irons. This isn't mine (it isn't that nice) but this is what we are mentioning. I've used mine on a gas tank before along with using it on a radiator.
Trick around here is to fill the tank with car exhaust, which displaces the vapors, never done it myself.
A company I used to work at did a lot of plumbing for the line of chillers we manufactured. We had a few pieces (copper to stainless) that we were supposed to soft solder together using an acid flux and a torch, but there were only a couple of people who could do it; I used to just use silver solder as it was a better joint and didn't require using the acid flux. Someone brought in a fuel tank for a snowmobile that had a soft solder joint that needed to be fixed; the guy who did it used a small tip on his torch and acid flux, fixed it up with 95/5 solder and did a beautiful job on it.
Heat the area with a propane torch to get the old solder to melt, brush it clean with a steel brush. Then put on some flux and melt in some new solder and you should be good. Sent from my SM-T350 using The H.A.M.B. mobile app
Lots of great ideas & suggestions, I really appreciate it. I guess I kept thinking I could just add some solder without melting the old solder. Since I don’t have any irons to melt solder at a small point, I will have to heat it up to flow more solder in place which will flow the old solder together with the new vs stacking it. I’ll let ya all know how it goes. Sent from my iPhone using H.A.M.B.
I have used this method to weld on gas tanks.... works good... Use exhaust from any engine... Lawn mower or whatever you have handy.... LynnW
To do this job properly you must remove the filler completely from the tank, clean both sides back to bare metal, re tin them, rivet the filler back on then resolder it. Solder is a capillary joint which means that the solder is sweated into the lapped joint which gives it strength along with rivets. ( Use your soldering iron to sweat the solder into the joint) If it has been leaking it means that the lapped joint has failed and although you might its is clean it won't be and solder will not flow into the joint to seal it properly. Been doing this sort of work for 55 years.
Solder up your leaks. Then what I do ,I paint the outside of the tank with the aluminum pigmented moisture cure which is impervious to gas . Any pinholes you would have would be sealed ,kind of like a double whammy
I decided to do the following: I wiped the surface down with a 50/50 mixture of muriatic acid & water. I used the acid core solder but decided to not use the flux I would if joining copper pipe (with lead free solder). As soon as I begin heating it a chunk of solder popped off. I’m assuming the acid/water liquid got under it to cause that. So after a pause to analyze what happened, I continued. Honestly I was quite surprised at the low temperature it flowed at, but it flowed out really nicely! Typically with copper pipes I’d be applying heat 2-3 times longer than I did here. I’ll test it in a while to see if she’s got any other leaks & that this one is good now. Sent from my iPhone using H.A.M.B.
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