Thread: Question on plumbing – soft solder or silver solder or brazing

Soft solder is ok for plumbing although a lot of plumbers use silver solder. A lot of plumbing capillary fittings come with solder incorporated in the fitting.

Fridge mechanics use silver solder because it will take much higher pressure.

I think they usually use brazing for general repairs on steel, brass and bronze.

Originally Posted by Theva

Hi,

I have a few questions about the differences between soft solder, silver solder and brazing in association with copper tubes / plumbing.

Which method is used for what?


Regards,

Theva :confused:

Soft solder is the weakest of the three, but also the cheapest. In Victoria, silver solder is used where ever copper and brass fittings are to be soldered.

I've never heard of brazing being used on copper. Requires more heat than either soft or silver solder, perhaps too much for copper plumbing pipes.

Having said all of that, the use of PVC instead of copper is becoming more and more widespread every day. Can't say I like it but its hard to go against the flow.(no pun intended)

HTH,

Mark.

Silver solder seems to be the most popular because the fittings are generally cheaper than the yorkshire ones with soft solder in them.

Soft solder is rubbish don't use it. Silver solder is more the standard but if you want to go topshelf brazing is the choice of champions but requires Oxy/Acetylene to use whereas silver solder can be done with LPG.

Thanks guys,

Now I understand the terminology . So, it is silver solder for plumbing.

Can anybody suggest a brand of silver solder and a suitable propane torch?

Regards,

Theva

Originally Posted by MarkV

but if you want to go topshelf brazing is the choice of champions but requires Oxy/Acetylene to use whereas silver solder can be done with LPG.

You can braze copper pipe with Mapp gas (LPG and acetylene I think) and the mapp torches are about $70.00 (dont use propane/butane/LPG torch) and if you use 15% silver brazing rods on copper to copper you dont even have to use flux. Best to get a heat reflector thingo for the torch though to deflect heat all around the pipe.

As a former plumber I use 2% silver solder which was ample for copper to copper or copper to brass. Higher percentages of silver (which are a hell of a lot dearer) are for more refined work or perhaps what has been requested in the specifications.
No flux is required on copper to copper provided the joints are clean. I use it (watered down) as it helps the solder to run around the joint if you are in a tight spot. Copper to brass needs flux. Ive never had much success with LPG/acetylene and prefer oxy/acetylene which burns much hotter and the job is done quicker.

Cant say ive ever seen a 'heat reflector thingo'. If using oxy/acet keep the torch gently moving or use a slightly feathered flame so you dont overheat the copper which will cause it to crystalise and breakdown eventually, sometimes years after it has been installed. Then you have a leak somewhere hidden in the walls or under the floor. Touching the rod on the joint will tell you when its hot enough to weld.
Jack

The heat reflector thingo clips on the end of yer torch and deflects the flame so that the opposite side of the pipe is heated also which makes it quicker/reduces heat loss. Mine was optional with the torch.

My two cents ...

I thought brazing was the correct thing for gas lines, as the copper is usually thicker and that is what was the "standard".

Silver or soft solder for water lines with a LPG torch is what the plumbers I've worked with.

Ok maybe only my 1 cent worth ;-)

JR