Checking in...

[Gas_mantle]

Hi Gary

I'm sorry it hasn't panned out as you wanted but from what I can see it looks to be a nice little boiler once you can sort out a few snags. I'm contemplating making something similar as my first boiler build so I'm interested in what other members say.

Maybe its worth starting a new thread in the 'Boiler' section on the forum with a bit more detail of how it's made and what the problem is etc 

[Ramon Wilson]

Hi Gary - Commiserations - been there and know just how you feel 

As Stuart says, and you are aware, soft solder is really a big no no near silver soldered parts. Personally, given that it is on the outside and easily accessible I would flux the whole end really well and use your lower melting point silver solder to run a fillet around the area.

A silver soldered part takes a higher temperature to remelt so you should be able to do that without affecting the rest but even if you do get it hot enough to re melt that should not be an issue to worry about with plenty of flux on.

Do make sure it's scrupulously clean all over that end beforehand though - looking at the pics it really needs a good pickle before you tackle it

Hope you make a successful recovery

Tug

[gary.a.ayres]

@ Peter - thanks. I'm a bit disappointed but not surprised. That leak was too easy to 'fix' when I air tested it   
My gut feeling is that I can fix it. I'll stick with this thread for now and try what Ramon suggests. If that doesn't do it for me, I'll post in the Boiler section.

@Ramon - that sounds good, thank you. Looks like I'll be needing a new lot of citric acid, as my original bucketful now looks like something out of a horror movie.
If it were you, would you use a small oxy/mapp torch or just blast the whole thing with the Sievert?

[Zephyrin]

 Hi,
stopping a leak in a silver soldered boiler is not difficult, the boiler will not fall apart upon heating...
You need absolute cleaniness, brazing flux and a propane torch for a rapid and localised heating, remove heating as soon as the brasing rod melt in the right place, that's all.
 
Caulking with soft solder also requires a meticulous cleaning of the parts too, not very accessible by the way, so once cleaned, go for brasing !
and remove the plug to allow air to escape during heating !

[gary.a.ayres]

Thank you Zephyrin - that's reassuring.

Cool name, by the way   

[Ramon Wilson]

Hi Gary - good advice there from Zephryn  . Yes I would use your Sievert to get a good all over heat at the relevant end. If you can protect the rest of the boiler with some firebrick to isolate the major heat where you want it.

If it's really clean and you place a ring of your low melting point solder around the offending area it should flow just as the heat is right for it and not the surrounding areas, once that occurs back  it up with a bit more with a stick of solder .

Can't stress it enough - mega clean, lot's of flux and a good amount of overall heat. Good luck with it 

Tug

[Tennessee Whiskey]

I’m really interested in this as I’ve done no silver soldering, but, soft up to 6”in diameter. I would think you could prep the outside of the tube and flux up, and put a bit of solder a the 12-3-6-9 area and apply the heat right down into the tube, concentrating around the inside of the joint    Just thinking along with y’all

Cletus

[gary.a.ayres]

Tug and Cletus - thanks both very much for your thoughts - very kind of you.

TBH I can see how both of your approaches could have their merits, though the small size of the boiler would mean that if I use the Sievert it would inevitably heat all or most of the end of the boiler, which as you suggest Tug might be a good way to go.

The small oxy/mapp torch might be able to point a flame down the tube, though whether that would create enough heat I'm not sure. I guess I could always try that first - it would be a neat solution if it worked. I did use the oxy/mapp to solder on some a couple of pipe nipples last night and the pipe ends were red hot in no time (hotter than I intended). For an intense and very localised heat it's pretty good; for a broader area the Sievert is the weapon of choice.

What I have gleaned so far from Tug, Zephyrin and Cletus is that it's not an insurmountable problem, that cleanliness is paramount (the boiler is back in the pickle already), that a bead of solder round the end of the tube should do the job, and that there may be more than one way of applying the heat to achieve that.

Brilliant so far guys - much appreciated.

[NickG]

Hello all I would have thought easy flow 2 would be the way to go, but I too have thought of and used comsol before. I’ve been warned off mixing soft and silver solder before - what are the issues?


Sent from my iPhone using Tapatalk

[gary.a.ayres]

Hi -

from a somewhat non-technical perspective: I think the lead in the soft solder makes it impossible for hard solder to stick to anything it has touched. Perhaps someone more knowledgeable than me will explain the metallurgy of this...

I'm using silver solder and easi-flow flux, and my aim is to stick with this if I can rather than use soft solder for the repair..

[john mills]

The propane for the general heat the hole boiler will absorb a lot of the heat the oxy will be more concentrated
used localy to bring the area to final temp on the copper around the tube the tube will heat quickly watch the
temperature as it creeps to were you want it.dont get the tube too hot.The oxy is good to get local area a little hotter when the solder doesn't won't to run in a spot like the spot that missed in the first attempt.
    At this stage you can reheat repair with silver solder once you use soft solder you can't go back to the higher temperature required for the silver solder.   

[gary.a.ayres]

OK, thanks John.

Sounds good - overhall heat with the propane, then oxy/mapp on end of tube prior to applying silver solder.

Makes sense to me - thank you.

gary

[john mills]

The tube plate flange area will take all the heat the tube is thin and will heat easily your job is to get the plate hot enough before the tube gets too hot while the plate is not hot enough .

[gary.a.ayres]

OK John - thanks for clarifying 

[Jo]

Gary your main problem will be that the rest of the boiler is going to attempt to pull the heat away from the joint causing a hot end of the boiler where you are working and a cooler opposite end. As Tug says the use of fire bricks means that once the overall boiler has warmed up the firebricks will keep the general heat in the boiler, that will allow you to bring the local area around the offending flaw up to temperature for the re-silver soldering operation. (Uneven heating can cause these repair jobs to cause other flaws if you have temperature gradients and can kill the flux if it takes too long to get the required temperature  )

You want to flux around the tube with the flaw but avoid the flux going elsewhere. By having a thin ring of silver solder round the offender in the flux you will see it melt and once it has flowed that is when to take the heat away... then take the fire bricks away to let the whole boiler slowly come down to normal temperature before pickling.

I hope you are going to remove those nasty sharp looking burrs around the insides of the tubes 

Jo