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Hard Soldering


Gluestick
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Can anyone please advise me about Hard Soldering?

I am about to tackle installation of oil fired central heating. Lucky me!

There seems much conflicting info about soft soldering, hard soldering and brazing.

With a pressure reducer/regulator fitted (to avoid over-pressure bursts and leaks) is it OK to solder pipes? If so what solder please?

Also, has anyone tried brazing 22 m.m. French copper pipe (it's thicker, I know!) with a MAPP lamp?

Or does it really require Oxy- Acetylene?

Many thanks.[*-)]

 

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The easiest way is to use a propane torch with a wrap around head (don't know what the proper name is) - these are plenty hot enough but the flame spread is large making them difficult to use near beams, skirting boards etc. Oxy-acetylene gives a much sharper flame but requires more skill/practice to make reliable joints. You can braze brass to copper using special flux but is tricky so it is ok to solder the end fittings at the rads., for example, otherwise it is best braze up sections in a vice and fit them when cool.
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For a number of reasons, not least the hard soldering question but also the relatively high water pressure. I decided that my oil fired CH weould be on the UK system, soldered joints and a header tank rather than the mains pressure french system. It has worked fine this winter, I only fired it up in September but it did  "exactly what it said on the tin".

www.leschenauds.com

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My next visit is going to involve plumbing, ie: putting the downstairs shower room fittings in place. I shall put the plumbing in, and leave final connections to the local guy.

Any pointers as to what sort of gas torch, solder, flux etc to buy?

I can soft solder like a (semi) pro, here in the UK, but haven't tried hard solder or brazing..........although I once brazed something in metalwork when I was 11[:D]

 

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My French isn't too bad: but not too good either!

I believe (dangerous!) that hard solder is what we would call "Silver Solder": French solder seems to vary considerably and it is hard to decide which type to use! Hence my original question.

Looking at Opel Fruit's head thread, it is extremely informative and has a wealth of information.

Years ago, I would use Oxy-Acetylene for brazing and silver soldering, using Borax as the flux for silver soldering: mainly Tungsten Carbide tools tips for the machine shop. I gather that most French plumbers still use Oxy-Acetylene or Oxy-Propane/Mixed Gas and braze pipeworks.

I have carried out much pipework and plumbing in the UK using copper tubing: even very high pressure (up to 400 psi) uses, such as compressor hydraulic testing, using very fine capillary (i.e. 'fridge) tubing and simple soft solder (Mechanical Grade), with no bursts and no leaks. However, I do accept that the hydraulic effect of fluids in pipes can strain joints, particularly with "Water Hammer".

Oxy-Accetylene is a very expensive commodity in France: small cylinders will run out rapidly, too! Hence my question concerning MAPP.

With some early copper pipe leaks, well massive bursts, really, in the greniere, (French plumber and shower and hot water feed into kitchen: merci bien, Franck!), I did buy a simple small blowlamp,  soft lead-free solder and decapitant from Mr Bricolage and that did the trick. Wifey  able to wash up, both able to shower and wash and no immitation Niagara flooding down through the ceiling! Not fun after being up at 3.00AM for an earlier shuttle, though.

However, for the heating, I do need this to be very secure and burst-free!

I am still looking for a small propane tank, with the standard Butane/propane screw fitting, as I have a spare Sievert plumber's blowlamp: the gas bottle I bought, firstly, once I took the plastic seal cap off, was a sort of bayonet push fit jobbie. No use for the adjustable industrial gas regulator I had already modified back in Blighty, with a standard French male propane/butane coupling. Don't fit!

The guy in the fuel station at our local Champion was very helpful and kindly gave me a new regulator for the bayonet bottle: but it's not adjustable: and I do like to turn the wick up and down, according to the job in hand.

Ah well, Easter I shall be back over in la Belle France and see how we go from here.

 

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hi

       ok this is one of the questions always posted on this forum, and it always stumps me ....

     why........ because if you are going to fit a preasure reducing valve to limit  it to less than 3 bar why hard soilder ??? i can under stand before the valve !!! but why after ??

         dave

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[8-)] Dave:

Is it because they have always done it like that? I gather that in certain cases, any bursts subsequent to installing the heating etc. might not be covered by insurance?

I understand from Opal Fruit's very informative post, that early French plumbing, particularly central heating, used what I would call gas barrel, so I guess that brazing is the ideal way to join this. Welding can have pinholes: solder is not really effective.

Of course, joining copper tube with Cupro-Phosophorus (which is apparently what they use) isn't as strong as Silicon-Bronze (which is the "normal" type of filler rod used for mild steel, sheet fabrication etc.). But it's far stronger than even mechanical solder.

But then I am still trying to find a definitive answer to another old question: must your chimney be swept once a year by a registered sweep? Some say that if not, any subsequent fire would be excluded by insurers. However, my french handyman (who kindly swept my chimney last year as a favour: has all the proper kit) said that this is nonsense. Not because he wanted the work, he charged me peanuts.

Ah me, well I'll keep on looking and hopefully, learning!

Again, Steve, I don't know is the answer to that one! Perhaps some other forum member can throw some more light on this?? Using Speedfit or pushfit would indeed save a lot of agro: and time; and cash.

 

 

 

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