How to stop torch melting existing joint?

[Albumen]

About to (maybe) do some soldering, on 15mm pipework, using solder-ring fittings. I've done a bit of soldering before, the torch is a nice Rothenberger. But I'm not vastly experienced, so I think that I tend to use too much heat (though I could be wrong). The only joint that's leaked was joining onto existing that still have some water in, which ran back.

This I'm about to do will be joining onto existing, but vertical pipework. So I can drain it at least until it goes vertical. Though I'm still nervous about water residue making steam or something.

Anyway, the question. If you're solder a solder-ring fitting, what's the nearest you'd be happy working to an EXISTING soldered joint on the same pipe? Presumably a wet rag round the existing joint might help to dissipate heat. Or is there some sort of heat sink available?

Thanks in advance.

 

[John D v2.0]

I soldered around 5cm away on 28mm pipe with no issues, just made sure the flame wasn't going that direction. With a wet rag you'll be fine, I didn't even think to use one

 

[Elkato531]

Try not to overheat the joint your making. If the nearby joint is good, the solder will melt and then re-solidify with no harm to the joint. I've soldered within a few mm of old fittings with no problems.

 

[Hot&Cold]

The solder in the adjacent fitting may melt,you will see the solder brighten up. Just have your flux brush ready give it a 360 degree brush of flux and a stab on solder.

Job done

 

[Doggit]

As well as the very wet rag trick, you can also put a pair of mole grips on the pipe; but for walls etc, there is cool gel spray that will form a heat barrier. Just don't get any on the pipe, or you'll get nowhere with it.

 

[Albumen]

Thanks folks. Having looked at a photograph I took, I'm fairly sure that the 'joint' I'm worried about, under the floorboards and inaccessible, isn't a soldered joint at all, but a bend. I did this myself and I was obsessed with having as few joints as possible in a void I knew was going to be totally inaccessible (without a lot of damage). So I remember doing some fairly 'artistic' bends just to avoid joints, even soldered ones.

 

[durhamplumber]

you can also put a pair of mole grips on

That tip is definetly pushing your luck!!!

 

[Doggit]

Why Durham; as many here have said that the joint might run, but reseal itself, why would mole grips acting as a heat sink, be pushing your luck. Explain please.

 

[Hot&Cold]

I'm worried about, under the floorboards

Best check you have adequate house insurance before firing up the torch,Diy has limitations when it comes to an insurance claim

many home insurance providers do not cover advanced diy but minor diy yes

get any approval in writing via email,you know it makes sense

 

[John D v2.0]

Yes on that note I got accidental damage insurance as part of my normal policy and it was hard to get a specific definition of what was covered.
Basically they said if I'm decorating and drop a tin of paint they'll pay for the new carpet but not replace the tin of paint.
They said if I take on a project I'm not competent like major structural work, that wouldn't be covered if something went wrong due to my lack of understanding.
I took that to mean they cover side accidents caused by mistakes in preparing, but not the work itself.

 

[Hot&Cold]

Diy/self build temporary insurance is available,existing household insurance is very limited John D v2.0 has an example above.

 

[durhamplumber]

Why not mole grips???..the OP is not v experienced at such matters.If the mole grips are too tight he will nip or distort the pipe......Simples...not to mention burn himself taking them off

 

[motorbiking]

flame goes on the pipe not the fitting as this ensure the solder doesn't melt out before the pipe is hot. I normally add a dab of extra for belt and braces.

 

[Doggit]

Why not mole grips

Ahh, never thought about it from that point; I'd assumed he had a modicum of sense in the way he's handling things.