Silver Soldering Boilers.

[ebeneezerParticipant @ebeneezer]

Hi I have had two attempts at silver soldering the end caps on my boiler both unsuccessful. I am using Mapp gas with a Rothenberg torch. This works great the smaller jobs not the end caps. Even though I’m using fire bricks. It would appear I need a better heat source. obviously propane and a propane torch would be the answer. Could anyone tell me a reasonably priced one to buy?

Cheers Mike

[bernard towersParticipant @bernardtowers37738]

you will get good advice from CUP alloys

[noel shelleyParticipant @noelshelley55608]

As Bernard has said CuP will offer advice. You do not say what size boiler, but the bay will have plenty of secondhand equipment. Like so many things in life how much will you use it, a 4Kg bottle of Propane will work for a few jobs but per Kg the gas is much cheaper in a 19Kg if you will use it a lot. Sievert or Bullfinch are 2 good names and a burner of about an 1″ dia may work depending on size of work. A sievert 2943 burner is a good one with the handle/holder, you will also need a min of 3m of hose and a regulator for 0 – 4bar pressure. A good hearth is also needed. Where abouts are you, joining a club might be a good move. Good luck. Noel.

[ebeneezer]

On 15 March 2025 at 09:53 ebeneezer Said:

Hi I have had two attempts at silver soldering the end caps on my boiler both unsuccessful. I am using Mapp gas with a Rothenberg torch. This works great the smaller jobs not the end caps. Even though I’m using fire bricks. It would appear I need a better heat source. obviously propane and a propane torch would be the answer. Could anyone tell me a reasonably priced one to buy?

Cheers Mike

What ‘fire bricks’? Vermiculite ones for barbeques are very good and coal fire or night storage ‘fire bricks’ are heat soaks and therefore rubbish. Likewise a piece of Rockwool roof insulation is good, but the glass fibre version will melt.

Be aware that a large torch will also need the large diameter bottle.

Bullfinch or Sievert both supply torches that take interchangeable size heads.

A lot of cheaper stuff is out there but mostly aimed at roofers so have a large but gentler flame.

[derek hall 1Participant @derekhall1]

CuP sell a great little hearth! As well as everything you need to carry out a successful soldering job.

Many years ago I tried using night storage fire bricks, as Dave says, they are totally wrong for the job as of course they just absorb heat. I did wonder at the time why my component to be soldered was never getting hot enough !

 

[noel shelleyParticipant @noelshelley55608]

A clue as to the type of “fire” brick. If it’s heavy it is unlikely to be any good if it’s light it will be good. Ceramic fibre is good, night store bricks worse than useless. The CuP hearth is fine for small work but we don’t know the size of the job. Old bricks from a pottery kiln will be excellent. For this size of work /burner the size of the bottle should not be a problem, at least until the bottle is nearly empty. If your near me you are welcome to see and try my gear, a full range of Bullfinch burners and oxy propane. Noel.

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