Boiler making advise

Hi,

I am going to make a myfordboy vertical boiler. It is 2.5" dia 5.5" long with a 22mm central flue. It has two bushes at the top and two in the side.

I have a Sievert Cyclone 3524 burner (3KW) and have CupAlloy 455 silver solder (low temp)

From what I have read I should do a two step braze. First the end caps and flue using a higher temp solder, then the bushes using a low temp solder.

My questions are;

Would a 3KW burner be hot enough to use a high temp solder?

Would it be possible to solder the whole boiler using low temp solder? i,e, do the bottom, then the top and its two bushings, and finally the side bushes.

Thanks

Adrian

IMO you will struggle for sufficient heat with your Sievert nozzle. To succeed you'll need very good insulation around the job. I see no reason why you couldn't try with 455 for the entire job to give a better chance of sucess.

I think that I'd treat myself to a burner nozzle one or even two sizes larger.

Clive

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Hi Adrian,

A question I often ask, Why didn't you ask your supplier of equipment and silver solder?

They are not a company that simply takes your money and leave you to get on with it. You can draw on the 100+ years of collective experience to help.

A couple of years or so ago, they were demonstrating with the help of Western Steam, the building of a similar boiler at the Midlands exhibition.

Who knows. As a customer, their technical support is included in the price of the silver solder.

Regards

Keith

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Hi Adrian,

And thanks to Bill.

With one eye on the Antiques Roadshow!

if you bought the torch kit from CuP, you already have a bigger burner generating 7kw of heat.

If you didn't, then you have a choice. Buy a bigger burner or improve your chances of success by insulating the joint better with an insulating blanket. Readily available from CuP.

No reason why you shouldn't be able to make all the joints with 455.

Regards

Keith

Declaration of interest - despite retiring 7 years ago, I'm still on their books!

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As anyone who has tried to dismantle a silver soldered joint will know, it takes a lot more heat than it did to solder it in the first place.

If you're careful with the sequence of assembly and the amount of heat used on joints already made, it is easily possible to make a small boiler using only one grade of silver solder such as one containing 55% silver.

CuP Alloys is an excellent place to start (usual denials)

Brian

Thanks for the advice.

Adrian

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Bill,

Brian was merely pointing out that once a joint has been made, the reflow temperature is higher due to alloying. In this way it is possible to make joints one after the other using the same silver solder type. Not only applies to small boilers.

K

Thanks Kwil.

Brian

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