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Quite small Scotch boiler

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Team ricky:
Hi Chaps,

I thought I would move this mini project to the boiler section…..

Having just finished building two small marine engines I wanted if possible to build a matching more scale than central flue boiler, I’m always on a bit of a budget so I tend to wait until something pops up second hand.

The risk is there that work to date might not be up to standard so a very cautious approach needed.

Also check it’s designed well so it can be completed safely.

This little  boiler is 3.5” x 5.5”

It should run either twin no problems, They have 11x11mm bore and stroke double acting.

Onto what’s been done and needs work…..

So far only braise and silver solder have been previously used …
All finishing from here will be silver solder.

The boiler leaked fairly badly around one spot on the front head
The braise used to attempt a fix I mostly ground away to reduce the mass around the repair. This worked out well and the leaks fixed! In terms of construction strength the original joint was full and looked to flow well apart from the small section that leaked!

The next job is to make a water gauge mount/manifold, There were some holes in the shell which I will use to feed water in and out of the manifold.

A steam dome was made from bronze to give a good top level for the water gauge and spare steam outlets.

Next I filled the boiler with a little water and pressured with compressed air (1-2psi)
To establish any further obvious leaks, I tend to do this now early and often in build to catch any gaps opening up between operations.

I have a leak in about the worse place possible! Back head behind the dryback…
It’s tiny but completely un accessible!

I’m pretty sure a tiny drop of loctite high temp would plug it…. Other options are to cut away the dry back to provide access and service point for the tubes , I think a good way is to use a hole saw in the lathe and mount the boiler to the cross slide and go slow, Afterwards I would make a back plate and probably add ceramic to the dry back..

Next is boiler bushes make and fit

That’s about as far as I’m into the project 😁

Team ricky:
Pics

Team ricky:
Water gauge manifold

Zephyrin:
the second engine is the Marcher, the piston valve version, by J Bertinat, I would bet...a nice model.
for fixing the leak in the boiler I would remove the back chamber and rebrase the boiler, and test for leaks before mounting the dry back...

Team ricky:
Yes to the marcher :)

I built two both piston valve and a great first engine project! I’m almost there with you on committing to the cut out of the dry back :)

I might be able to find out today exactly what’s next !

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