Soldering pipes - quick query on temperature

[Grenage]

Hi all,

After a lot of reading, and watching a couple of videos, I shelled out on a Rothenberger Super Fire 2 kit; the kit came with a can of MAPP gas.

I had no problems on a test, and capping an old electric shower feed went fine (after I flushed the toilets...) but I'm curious about how quickly one is supposed to get the connector/pipe to temperature.

The videos I watched showed people heating the cap/elbow for about 5 seconds before soldering, but the caps seem to hit temp after about a second or two of heat, and the solder gets sucked straight up. The joins seem good, and they don't leak.

The torch is pretty impressive when it comes to output, so I turn it down to the lowest stable setting I can. Is MAPP gas that much hotter than propane, or am I creating a bunch of potentially awful joins?

 

[Burnerman]

Your Mapp gas is much hotter than propane or a butane/propane mix, and will get things to temperature very quickly indeed.
There's nothing wrong with that - in fact with large joints it is a blessing - but you mustn't overheat the copper. it will turn black due to oxidisation and you'll have to start again.
Mapp torches aren't for the beginner, copper joint wise - but its a marvellous chemical gas mix which propane won't achieve on its own, heat wise.
John

 

[Whitespirit66]

If you're drawing solder into the fittings, you're doing it right. If you weren't, you would have leaks by now. Make sure the solder gets sucked in all round - more care needed on bigger sizes.

I use propane, which is cooler but with modern torches, plenty powerful enough for normal plumbing. I wouldn't use MAPP unless I was doing lots of large stuff. I prefer the slow burn approach rather than blitzing it. I use quite a low flame, especially for 15mm which doesn't take much heating. You want to avoid overheating fittings, as this can mean the solder won't get drawn in and just beads down the pipe. There's a surprisingly fine line between just right and overdone.

Soldering is an art that takes practice, but the basics help - clean pipe and fittings, smear of flux - not thick, but not too thin and Laco flux for me. I always do the highest joints first and work down, because the other way could mean that higher joints over-cook from rising heat from torch.

Everyone has their own techniques.

 

[Grenage]

Ah that's good to know; thank you for the reassurance. I'd probably have started with Propane, but hey, I'm not going to leave a perfectly good can of gas laying idle.

I capped it about 20cm from a T-piece, so I wrapped a damp cloth around the nearby joins. If I'd been more confident, I'd probably have removed the T and just put an elbow in - much neater.

Cheers for putting my mind at ease!

 

[Steelmasons]

. I always do the highest joints first and work down, because the other way could mean that higher joints over-cook from rising heat from torch.
.

......or simply the solder will run out of the bottom joint and make a mess of the tube.