Boiler making

[andrew7931]

Hi there
I am about to start making a sweet pea and I was thinking of making the boiler my self just wanting to know if the was a type of silver solder I must use ? Also any tips on Making the sweet pea boiler would be most welcome thanks
Andrew

[gingerneer]

Hi Andrew

Have you under taken any boiler work before? As i would advise to practice on something a bit smaller to get a feel for the process and the heat need. Even with the small boiler's i have put together have need quite a bit of heat

Silver solder is sold by the diameter of the 'stick' and the composition (or the % of silver the 'stick' contains). The lowest % sticks CuP Alloys (no connection just a happy customer) sell are 455 or 55 % silver )the greater silver content in the stick the lower the melting temperature i would need to check but its about 615 degrees (the solder then has a slightly higher remelt temperature about 650 ish degrees i think). Conversely the silver solder in the stick the high melting temperature. I would advise that you start of with the highest melt silver solder 438 (on the throat plate and barrel joint) and work down to the lowest melting temp 455 for the final assemble of the boiler. Flux is important to for the temperature and length of heat needed will dictate which to use. I would want to use the larger diameter stick 2mm - 3mm, the smaller ones just melt near the heat not on the job.

While a Sweatpea boiler is simpler in construction than a normal loco boiler its going to need a lot of heat, at a guess i would want a lest 2 2" roof burners (make sure you have plenty of gas, nothing worst than running out half way through). A helper would be a must. But entirely do able. As long as you have plenty of heat, the job is clean and you flux every joint (even if you don't intent to melt it)

The Sweatpea construction book gives a good write up of putting the boiler together. Also the boiler inspector might want to inspect the inner and out parts before joining together. Its worth talk to him or them for any guidance.

I hope this is of some help and answers the question. Many people are put off building boilers its not a black art, just patience, careful planning, plenty of heat and cleanliness.

Will

[ejparrott]

Your local boiler inspector will want to inspect, it's now a requirement in the 2012 test code to which we are currently working. If you are not currently a member of a club, I'm afriad you'll have to join for this to happen if you ever want to get the engine certified to operate at a club. Once upon a time you could have just turned up for test with a fully built up engine. To a point you still can if it has previous certificates, but not a boiler that's never been certified.

[jma1009]

the only advice i would offer re Sweetpea is ditch the marine type boiler and fit a proper loco type boiler! you wont regret it!
will and ed's advice is excellent apart from the fact that johnson matthey now only recommend 2 types of silver solder for boiler work on copper ie silverflo 55 (630 degrees melting point) and silverflo 24. even those of us with a bit of experience with copper boiler making and silver soldering find silverflo 24 takes a bit of getting used to, as it melts at 740 degrees. with both types you need a long active aggressive flux such as tenacity 4A or thessco F.
you will get lots of advice if you keep us posted!
cheers,
julian

[andrew7931]

Hi
Thanks for the replies I have made a few copper boiler before but nothing to big I did use oyxy acetylene which give me a lot of heat but still had to use a propane burner to keep the heat in
I will be joining my local club which is Wigan I will keep you posted on my progress
Thank for reading
Andrew

[andrew7931]

Is there and good books to read on boiler making for the beginner?
Thanks
Andrew

[dfh]

Model locomotive boiler making by Alec Farmer is a good one, I looked for a second hand one but they were asking silly prices, so I got one out from the library, always a good source, cost just £1 for reserving it. I also have one by Martins Evans, a bit more technical with calculations etc for material thickness, but a bit dated now, thats also called model locomotive boilers.
David

[jma1009]

unfortunately as david says, the martin evans books are now seriously dated since the ban on cadmium silver solder in the UK and the very restricted range of silver solders for boiler making as a result.
john baguley's website ('baggo' on here) and the construction of his HELEN LONGISH boiler is the best and most well researched up to date stuff on copper silver soldered boiler construction. you might also like to have a look at my BOXHILL thread on here and the construction of the boiler recently if you want to do silver soldered stays on a loco type boiler.
cheers,
julian

[andrew7931]

Thanks for the replies I will have a look at your boxhill thread Julian do you know the website address for baggo?
Thanks
Andrew

[jma1009]

try the following onwards clicking on the green arrow at the bottom of the page

www.modeng.johnbaguley.info/locos/25inch/Helen%20Longish/helen7.htm

cheers,
julian

[Jim]

I'd also suggest you have a look a Julian's own excellent posts on building his boiler for Boxhill, they start about here,

modeleng.proboards.com/thread/6408/boxhill-martin-evans?page=22

Sorry Julian I missed your earlier reference to Boxhill's boiler.

Jim