Soldering/brazing a boiler.

Looking good Brian, just need to get hold of a lathe and then you can make a larger version of the wobbler to go with the bigger boiler

Brian, it would be nice if you could fit the support brackets inside the firebox, with the feet turned inward, that would look a little tidier, to match the nice work you have done on the rest of the boiler.

Ian S C

Jason : I use the big boiler to run the PM research engines. I am still looking for a lathe. I go to China on the 5th April....I wonder if I can bring one back on the plane ?

Ian : that is a good idea

You could stuff the lathe in your jacket, might be difficult getting through the metal detector though. Maybe you could make enquiries though, it might not cost the earth to ship it home.

Ian S C

I have a question, when silver soldering the end caps. does one apply flux to the surfaces and then push them together, or does one just apply flux at the joint after assembling the parts ? What about the washer by the chimney ? Would one apply flux on top of the cap and under the washer, or not ?

I have silver soldered various pipe fittings, but never a boiler.

1. When I silver soldered the end caps to the pipe I put flux on all surfaces and then pushed them together.

2. I applied flux to both sides of the washer, the top of the end cap on which is sits, and the chimney where it makes contact.

Here is the PM Research twin cylinder engine combined with my own boiler all fitted together on a single wooden base. I have made brass struts to hold the boiler with the feet facing inwards as per Jason's suggestion. There is a larger copper plate to take the twin funnel burner and it is separated from the boiler's copper plate by a 1mm gap. This is to stop the burner getting hot when in use although the small pins I have fitted to the bottom of the burners seemed to have solved this problem anyway.

Edited By Brian John on 03/04/2015 06:49:58

Edited By Brian John on 03/04/2015 07:10:23

Edited By Brian John on 03/04/2015 07:13:05

My old solder supplier (Miniature Steam) is no longer selling solder or bar stock. But he has assured me another supplier has the same solder (with cadmium to aid the flow ) so I purchased about $80 worth from him. I tried it for the first time today and it did not go well : I had to heat the copper up much more than usual and even then it did not flow very well. It seems very similar to the plumbers silver solder I tried a few months ago which had no cadmium at all. I did not end up with a nice shiny fillet of solder. It will probably do the job but it looks very unprofessional....''rough as guts'' is how I would describe it.

1. I am using LPG gas and this has worked for me in the past with the old solder. Should I be using a hotter gas ?

2. What colour should the copper be when the flux melts and it is time to apply the solder ?

3. Some people soft solder their boilers. What temperature of soft solder would be safe enough to use in a tiddler boiler ? I do have some 240 degree soft solder but I would think it would have to be higher than that.

Brian can you post the exact details of the solder, eg what is is described as and any make, spec, etc.

J

No, it does not come in any packing : I can give no details or description. I was told over the phone that it was 45% silver.

What should I be asking for ?

Edited By Brian John on 28/07/2017 12:57:13

Well 45% with cadmium should melt OK as that is what the basic proportions of Easiflo solder is/was and should not be any more difficult to use than what you had before.

The metal should just have a dull red glow as the flux turns to liquid when viewed in a dull room, you may not see it in bright sunlight.

J

That was interesting : I just tried the old solder. It was a bit better... but not much better. I wonder if the flux has gone off ? It is EZI WELD 602 and there is 1/4 of a jar left. I would have thought it would be good until the last drop !

I've not used the paste flux b t have a feeling it may have a shelf life once opened. Powdered won't go off.

I bought some new flux today from Bunnings. The EZI-WELD 602 silver brazing flux has been replaced by CA 602. It is the same composition but by a different company according to a few websites. The result is a big improvement over yesterday.

I am surprised the old flux had gone ''off''.