Soldering copper air pipes

[MG David]

I have done quite a bit of plumbing in the past using end feed copper joints. That was some years ago as I bought a brand new house 16 years ago and have done very little domestic DIY since.

Last night I was trying to solder air pipes for my new compressor and I was having problems. What I want to find out is have I lost the knack or was it just too cold out there so 28mm pipes were too much of a heat sink.

I have one of those none contact thermometers so I think I will try again and take some readings.

What temperature does plumbing solder melt at?

Could it be that my blow lamp is giving too cool a flame because the cold is limiting the gas flow?

 

[gavuk]

Most blowtorchs would benefit from being stored inside your warm house..at least before using ..are you using a good flux as well?

 

[MG David]

I am using active flux but it is quite old.

 

[gavuk]

try raising the temp of the gas by leaving inside for a while,this will increase pressure of the gas .....what kind of blowtorch ...not a pencil type ? ...

 

[brightspark]

28mm pipes take a fair bit of heating. especialy if u only have a small torch

 

[Jammy James]

Try puting a heat mat/ piece of alu under it to refelct heat

 

[rikrobson]

I had no bother with mine but did then in the summer, appart from one that leaked. re-sweated the solder and left the air back in. But didn't let it cool properly and has solder spray every where

 

[drivewasher]

When the flame goes green the coppers ready to solder

 

[MG David]

Thanks for your help folks. It is a proper blow lamp with a screw on disposable cartridge. Not like my Dad's old one which he screws a small camping gaz refilable onto!

 

[mike os]

preheat about 3-4" either side of the joint, plenty of heat then slowly run the flame into the fitting..... as you have noted 28mm steals heat fast,

 

[Bingy]

Have you tried using the yellow mapp gas bottles instead of normal black butane ones. These heat up things hotter.

 

[Slim Shady]

If I were you I would borrow someones o/a kit and at least silver solder the joint or better still braze it. When working in an other workshop the boss ordered the air line be soft soldered. It blew 6 times before he gave in.
Just my 2 cents

 

[kingkenny]

silver solder with mapp gas.