Eutectic Boiler Soldering

Hello all, I hope someone may help.

About 6 years ago after been made redundant for the umpteenth time I tossed my toys out of the pram and decided that I had retired ( i just didn't tell my good lady). I got a job on the evenings delivering curries, sold the jag and bought a 10 year old Scoda and did a lot of charity work. (keep going as you may see where I'm going with this) I then went into a factory and got the smell of suds oil something that I hadn't smelt since my apprenticeship some 40 years ago. I went completely unnecessary and totally gaga - I want to build a steam loco! (maybe I had gone completely loco)

I needed a workshop, but to build one I had needed to build an extension to the house to maintain equilibrium with the household authority. This all took some 2 years and a lot of money. (during this time I kept a bottle of suds available to have an occasional sniff of - for recreational purposes only)

I then accidentally got a contract as an international sales manager for a polymer machinery manufactures which lasted 3 years and took up most of my time, but the loco was always at the back of my mind and built a 16mm garden railway as compensation.

After I decided that I had retired for the second time, it was loco time. I need to equipe my workshop. As I like challenges I set a budget of £250 and after buying and selling on Ebay I now hay a nicely equipped workshop (boxford lathe with speed control, miller etc and a host of tools) and almost within budget. I have taught myself CAD etc and have started to use a lathe for the first time in 40 odd years.

After a lot of research the loco I have decided upon is a Sweet Pea with a variation of modifications. By accident I found a local fabrication company whilst delivering curries (yes I am back doing that, I enjoy it - no hassle no pressure and a lot of time to play on Ebay) to one of their late night working sessions and after talking to the directors I was allowed to raid their scrap bin. I also bought small lengths of steel from their stock when I needed it. As the relationship grew I was offered a contract for 3 days a week to set up and run a small machine shop to produce the parts for the fabrications that they produce. Back on to Ebay and they now have a small machine shop (I wish they wouldn't call it a tool room) equipped with a Colchester Triumph and a Bridgeport mill etc and for 3 days a week in full production, for the rest of the time I have joined the local model engineering society and have spent many happy hours there talking to the members.

Now at last here is my question. The main problem with my Sweet Pea is the Boiler. Everyone I have spoken to is very weary of building a boiler, but I cannot see why - am I missing something. The only problem I can foresee is my ability th silver solder it. (some years ago I decided to skim some plasterboard after watching some professionals it looked easy. That wall is the only one in the house that is now artexed!) I asked the Technical Director at work if he wold train me to silver solder. I explained what I wanted to do and he offered to do it for me, but was I sure that I wanted to silver solder it or maybe TIG welding the copper or even Eutectic soldering would be better. I explained that it would need to be passed by an armature boiler inspector who (like me) would probably have never come across these methods. He then offered to allow the boiler inspector to watch the boiler been soldered.

Has anyone got any ideas on these methods as I feel like someone who after asking to buy a Ford Escort was offered a Rolls Royce free of charge, is it what I want. HELP.

If you want to build the boiler yourself then do not attempt either TIG welding for which you need to be a coded welder or at least have samples inspected/tested before you weld the boiler and Eutectic soldering is simply not strong enough and will not with stand the heat.

**LINK** with some amendments in 2013 worth having a chat with your local boiler inspectors.

That leaves silver soldering the boiler, which is not too difficult and with a little practice should be well with in your capabilities. I say practice as I would not recommend just jumping straight in.

I actually find silver soldering reasonably easy as long as you remember one thing " parts need to be clean".

I've done lots of silver soldering and yes, its basically fairly straightforward. But I strongly advise you to get lots of experience before tackling a boiler.

Boilers are large lumps of copper which require correspondingly large amounts of heat for a successful job. Somebody at your club must have done one at some time, so talk to them. Have a look at the equipment they used and try it out. Start small and progress upwards; copper and silver solder are expensive these days and, despite it being basically simple, the sheer quantity of heat required can be very intimidating. Its normal practise to use two torches: a large one for getting the whole thing nearly up to temperature, and a small one for locally heating the joints to melt the solder.

I'm sure you can do it, but gain some experience on simpler things first.

Hello Martin

For the best website relating to silver soldering for model engineers visit **LINK**

Find all the information relating to alloys, fluxes and heating equipment

... Cheeky, but true.

MichaelG.