Sievert every time, get a starter kit and add burners as required.

https://www.gasproducts.co.uk/blow-torches/sievert-gas-blow-torch-kits/sievert-general-purpose-gas-blow-torch-kit.html

Calor gas cylinders can be found quite cheaply at car boot sales and the like, don’t worry about size or condition once you have the cylinder you just swap it with the size you prefer at your local calor dealer.

Check first – my local Calor dealer will only replace with the same size cylinder.

Edited By Bob Unitt 1 on 10/03/2022 09:56:24

Propane is hotter than Butane and I would think that Map cylinders are he dearest way of buying gas

Roy

No, it's for butane; you need propane. Temperature and heat are different things. Many of the small torches will reach the required temperature for silver soldering, but will not be able to supply enough heat. When I started silver soldering I had all sorts of problems, even with a Sievert torch. Turned out I didn't have a big enough burner, ie, not enough heat. By the time even small work got up to temperature the flux was exhausted. I second Sievert and propane.

Andrew

The map gas set from toolstation is very good, the burners are easy to change, but I do not think they are good enough for a boiler. A very small one probably. I think the map set is more for silver soldering smaller parts together. Also: as you hold the bottle all the time your arm may get tired (Or minimum mine does….).

On a boiler the heat will "run away" because of the good thermal conductivity of copper. So you need plenty of power. The Sievert pro 86/88 burner has 7.7kW, this together with some thermal insulation (fire bricks) should do the job. Problem at the moment is to get a propane bottle. Some kind of shortage on the market.

Edited By Gerhard Novak on 10/03/2022 10:30:55

Hi Nick,

Sievert every time until propane heating does not fit your needs. This is likely really when you might want a more defined flame.

The mapp or map torch is ideal for a plumber. It has a slightly higher flame temperature but may not deliver enough heat because it is not burning sufficient gas.

Heating is probably the biggest cause of brazing (silver soldering) problems usually resulting in poor joints.

Look beyond the headline price. You could be heading for higher costs later.

Why not discuss your requirements with someone who appreciates and understand what you want to achieve? Try CuP Alloys.

Why ask a storeman in a plumbers shed? Alternatively read my book. Either way, you will understand enough to buy any pre-loved equipment.

But buy sievert.

Keith

No way is that torch going to work on anything unless it is very small indeed.

Use Propane and take heed of the size of regulator AND cylinder. For big jobs a small Calor cylinder will not provide enough gas per unit time.

As to torches and nozzles, most people say Sievert. I have a large range of Sievert stuff and an equally large range of Bullfinch torches and nozzles.

I much prefer the Bullfinch product, they are British made and they have an extremely good advice set up, if you need help.

When I was accumulating torches, the Bullfinch products were less expensive than Sievert. Both are good and should be your only choices.

Andrew.

Gerhard hits the nail on the head. The answer more about the ability of the torch to deliver heat, measured in kilowatts, than brand-names.

A lot of heat is needed to braze or solder large lumps of copper, especially if the lump isn't insulated. Heat isn't temperature. Gerhard mentions 7.7kW, which is certainly more powerful than the Vortex Map Torch sold by Toolstation. Toolstation don't specify their torches output, but the burner and cylinder are similar in size to my baby Sievert, which is only good for 900W. 900W is OK for brazing small parts carefully insulated by a firebrick igloo and is more than adequate soldering copper pipes, but I wouldn't attempt to braze a boiler with it. Not enough kilowatts.

Boiler work needs a big nozzle fuelled by a cylinder big enough to provide a high volume of gas. Cartridges are probably too small to deliver the necessary kilowatts. I'd talk to CupAlloys about the size of torch needed.

The original MAPP gas was a hot burning mixture of Methylacetylene, Propadiene and Propane, often used instead of Acetylene (also hot burning). Good stuff, but it's not made any more, I believe because Methylacetylene was a by-product from a chemical process now obsolete, and the amount of MAPP sold doesn't justify setting up a dedicated plant. Current 'MAP' gases are mixes of Butane, Propane and perhaps Propylene – they burn at a higher temperature than Butane and Propane, but are cooler than true MAPP. I think MAP is a bit of red-herring too – its about kilowatts rather than temperature.

Dave

Just on Friday at an EDMES meeting one member told me he couldn't get a calor refill because they had no small cylinders – bit of a run on them due to people perhaps cooking on gas to save electricity. He had to get a 19kg one to exchange.