Soldering brass fittings to copper

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Kilash
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Sun May 12, 2013 1:19 pm

I soldered for the first time yesterday ( 8) ), it went pretty well until it came to soldering my brass ball valve to the pipe. I kept heating the brass end, but the solder just wouldn't melt on touch. I took it apart again, cleaned it and fluxed the again, and still no solder melting. In the end, I had to dance my propane torch along with the solder, it melted in messy globs that I doubt made it inside the fitting. The ball valve was overheated too, as the plastic seal inside has loosen, still air tight, but the handle is a lot more loose now (which is a half blessing).

I checked it with an air pump, and indeed the whole thing is leaking from the brass valve and pipe joining, but the ball seal itself still works, thank the spud gods.

So now how to fix this leak. I thought about either sweat the thing again to pull apart the fittings, at the risk of further damaging the ball valve, seal the spaces with glue, or use my electric soldering iron to fix up the existing solder.

Advice?
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cammyd32
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Sun May 12, 2013 3:09 pm

The trouble with using a propane torch for larger fittings is it doesn't get them hot enough, especially seeing as copper based alloys tend to disperse heat really quickly.
On some valves you can actually take out the inside, if you can't then soldering on a fitting like that (unless you get an oxy-acetalyne set up) is definitely a no go.
Although If your really determined then you could probably do it by doing the following, although the chances of damaging the fitting are probably bigger than succeeding:
a) use a really low mpt solder
b) 'tin' the fitting before you try soldering everything together
c) keep heating the fitting when your feeding solder by heating from the opposite side, so the flame isn't directly melting the solder

I'm surprised that you actually found a solder-in ball valve fitting, usually they are compression fittings because of their heat sensitive components.
There are people who have done it with a propane torch, some ball valves designed for heat use Teflon seals so they don't warp or melt permanently when you heat them,

Hope that helps
jsefcik
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Sun May 12, 2013 3:25 pm

Solder on ball valve fittings are very popular,,, you might wanna try map gas its a lot hotter:)
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cammyd32
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Sun May 12, 2013 3:27 pm

Not in the uk, they are few and far between, especially in the smaller diameters,
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Kilash
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Sun May 12, 2013 3:47 pm

Is it gonna come off easy after heating?
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cammyd32
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Sun May 12, 2013 3:58 pm

If you heat just the copper pipe it's attached to near the joint, then it should pull off quite easily, to be honest you could just heat the solder directly and once it's soft just whack the fitting off the end with a soft mallet, shouldn't do any further damage to the fitting if your quick.
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Kilash
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Sun May 12, 2013 10:11 pm

Will try tomorrow, thanks guys!
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Kilash
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Mon May 13, 2013 6:41 pm

Tried heating up this morning, just wouldn't come off, solder is is solid even after a several minutes of heating with the tip of the torch. Any idea what I can use to seal it? Even new solder wouldn't stick anymore.
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Wed May 15, 2013 3:06 pm

Kilash wrote:Tried heating up this morning, just wouldn't come off, solder is is solid even after a several minutes of heating with the tip of the torch. Any idea what I can use to seal it? Even new solder wouldn't stick anymore.
Did you flux before trying to add solder? Solder won't stick to an oxidized surface.
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Kilash
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Fri May 17, 2013 9:36 am

Yea, applied good amount flux, just won't stick :( . I gave up and just teflon+tape the area, there's a slow leak where I'm losing about 5 psi every minute. I was really hoping it could hold air....
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dart guy
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Thu Jun 13, 2013 6:04 am

i think if you would place new soder in top of the exsisting link in like a cone shape it would block of the leak without futher damage and this may also help make the handle tighter
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