Silver Soldering

BlueLancer

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I have a loose fitting on the top of my Diesel Fuel tank, brass construction very heavy Navy Spec.Does anybody have any experience of the task. I also need to solder the mesh filter tubes in my sea cock inlets, as the joins have come apart. I can do normal soldering and can weld, but have never done any silver soldering is it the same as Braising, which I have never done before.Alternative, any recommendations of a firm in Thirsk area who could do the job.
 

CreakyDecks

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Silver soldering is very similar to brazing, apart from the difficulty due to your eyes watering so much when you see the price of the rods! It can be done with a small propane torch. Clean everything carefully and use the right flux.
 

earlybird

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Even the lower temperature silver solders melt at around 650 deg. C. That's red heat, reaching that temperature on a heavy brass tank will require a major source of heat. (Brass is very heat conductive). Not a good idea on a fuel tank pehaps unless well cleaned out.
Silver solder is also sensitive to dirty components, so scrupulous cleaning is required.
Best perhaps to get a skilled operator with oxy acetylene IMHO, who won't burn holes in your tank, or else consider soft solder.
If your seacock mesh filters are brass or similar, I'd expect a silver soldering flame to burn big holes in them. Again consider soft solder.
 

maby

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Be very, very careful of soldering any kind of fuel tank with a naked flame! Any fuel remaining in the folded seams or other nooks and crannies will rapidly evaporate, mix with the air in the tank and...

Many years ago, I worked as an apprentice in a little engineering workshop. One day the spout dropped off the foreman's favorite oil can, so he decided to braze it back on. The bang was surprisingly loud and the oil can opened up like a flower blooming. It took ages for his eyebrows to grow back again!

If you do decide to go for it, steam it out for a long time before getting a blowtorch anywhere near it - make sure it is thoroughly heated through and the steam flows well. Even then, make sure you're wearing protective glasses and gloves would be a good idea too!
 
A

angelsson

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I have a loose fitting on the top of my Diesel Fuel tank, brass construction very heavy Navy Spec.Does anybody have any experience of the task. I also need to solder the mesh filter tubes in my sea cock inlets, as the joins have come apart. I can do normal soldering and can weld, but have never done any silver soldering is it the same as Braising, which I have never done before.Alternative, any recommendations of a firm in Thirsk area who could do the job.

Had a similar problem with diesel tank fittings, I had drilled two new holes in the tank manifold cover to take a feed and return for a fuel polishing system. The cover has some 40 plus bolts holding it in place so drilling the simpler option. (the drill swarf collected by a well greased drill point on breakthrough)
I did not, nor would I attempt braising the fittings to the tank, high local temperatures are required, for the solder to run correctly as has been pointed out by others.

I countersunk the holes in the tank top, the fittings were almost a press fit in them, and used a small amount of epoxy under them.
Although they are on the surface of the top of the tank and do not need to be leak proof I made sure they were even though it not critical in any way.
 

rotrax

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Be very, very careful of soldering any kind of fuel tank with a naked flame! Any fuel remaining in the folded seams or other nooks and crannies will rapidly evaporate, mix with the air in the tank and...

Many years ago, I worked as an apprentice in a little engineering workshop. One day the spout dropped off the foreman's favorite oil can, so he decided to braze it back on. The bang was surprisingly loud and the oil can opened up like a flower blooming. It took ages for his eyebrows to grow back again!

If you do decide to go for it, steam it out for a long time before getting a blowtorch anywhere near it - make sure it is thoroughly heated through and the steam flows well. Even then, make sure you're wearing protective glasses and gloves would be a good idea too!

Hi, as someone who has repaired over a hundred motorcycle fuel tanks I have a routine which never fails. I drain the tank,if there is any fuel in it. Put in 1 litre of water soluble degreaser and swill about for at least five mins. Remove all taps and caps. Pour degreaser back into container for further use. Put over drainhole and put a hosepipe in the filler orifice,turn on full.Leave for 1 hour. Light up oxy aceteline torch,adjust flame and at arms length plunge into filler orifice.99.9% of the time no reaction-once in a while a wet ffsssttt noise. I did this to a BSA tank in the sixties. The foreman thought he would weld it.He asked if it was prepared and I said yes. Suddenly there was a bang and the tank went through the workshop window. There were two blue BSA Bantam tanks that required welding that day.........
 

DownWest

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Instead of silver soldering, can you use some sort of threaded fitting/sleeve to secure it to the tank? On the lines of an olive fitting drilled through so the copper(?) tube passes into the tank and is secured by tightening up the olive and the other end of the fitting clamps some washers and gasket seals to the tank skin.
DW
 

BlueLancer

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All the fittings in the tank are soldered in. This particular fitting is in the top of the tank and just spins if you try to attach a pipe to it, its for the fuel return pipe.The tank has been empty and the access plate removed for over a year. I looked at soldering so it matches the rest, I may try and get a threaded fitting to fit with a lock nut underneath.
I will try soft solder on the mesh.
 
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