A couple of years ago I got a Graham Industries VR1A and made a simple horizontal boiler which was heated with gel fuel to run it. This worked well but I decided to make a better steam plant for the engine… because I can.

While visiting Blackpool Model Boat Show last year I acquired a Brue boiler made by Helen Verrall-Stait for a very reasonable sum. The boiler came with wood cladding and a chimney but no fittings. Most importantly, it did come with a test certificate and paperwork.

A quick rummage in the bits box produced some fittings and the chimney was replaced with one from another boiler.

I wanted the burner tube at the rear of the boiler and of course some means must be found to secure the boiler to a base. (Otherwise it may wander off when I'm not looking…)

So this is what was required –

• A firebox for the boiler which should be raised 12mm to allow a Bix 009 burner to function efficiently and have sufficient ventilation.
• A means to affix the firebox to a base.
• It should have a door on the front so the burner can be lit (and to allow for observation of the burner flame).

Parts marked out ready for drilling.

The firebox will be made from 0.5mm brass sheet, mounting brackets from brass angle, boiler supports from brass flat section.

For those who like to know the size of things, where it is practical to do so, pictures are taken on a 1cm grid.

Edited By Henry Artist on 09/04/2017 06:41:12

With the holes in the firebox drilled it is guillotined to size and the opening for the burner cut with a fretsaw. Horizontal cuts are made for the firehole as it is easier to do this while the metal is flat. The rest of the material is left in place to provide structural integrity during the rolling and silver soldering processes.

1/32" rivets will be used as pins to locate the brackets and supports during silver soldering.

I was struggling to come up with an effective design for a latch for the firehole door which is 20mm wide. Then I realised that if I angle the front of the firehole gravity will hold it shut.

With the silver soldering completed it is time to make the base plate for the firebox.

A piece of aluminium sheet (0.9mm) and brass sheet (0.5mm) were cut to size. Transfer punches were used to mark the location of the screws.

The aluminium sheet serves several purposes –

• It prevents unwanted marks on the brass sheet.
• Eliminates burrs on the brass sheet during drilling.
• Ensures correct alignment of the mounting screws during soldering.
• Will help to prevent the nuts being soldered to the scews. (Been there. Done that.)
• Prevents distortion of the thin brass sheet during soldering.
• Will act as a drilling template when it is time to mount the steam plant on a board.

To make the hinge on the firehole a length of 2mm OD, 1mm ID brass tube was silver soldered to it. The ends of the tube were cut flush with the sides of the firehole and the middle bit milled away. A similar procedure will be used to make the hinge on the firehole door.

Also in the above picture you can see the Bix 009 burner that will be used in this project and a second firebox for a marine steam plant.

The aluminium and brass sheets are taped together and drilled.

A test fitting shows that they go together in a satisfactory manner.

Four brass M2 screws are soldered to the underside of the base plate and the firehole is soldered to the firebox. The inside of the firehole is cleaned up with needle files.

Some views of the firebox without the boiler in the way.

Two screws will be used to secure the base plate to a board. They are hidden inside the firebox in a vague attempt to keep the appearence of the finished steam plant fairly neat.

Stainless steel M2 threaded rod is used to clamp the firebox to the boiler. This will (eventually) be cut to length.

I have a few "helpers" Neil.

Time to start putting things on the base board. You can just see it in the picture with the minions.

You can use anything you like for a base board. Generally whatever you happen to have to hand. This one is actually a wooden chopping board bought in the local supermarket. It measures approximately 40cm by 28cm and is made of beech which is a nice hardwood.

It comes shrinkwrapped in plastic which saves me from having to wrap it in clingfilm before glueing sheets of paper to it. (A spray adhesive like 3M Craft Mount works great.) You can glue the paper directly to the wood if you like. To get it off later just soak the paper with white spirit to release the adhesive. Obviously this works best on unvarnished wood. Cartridge paper is ideal but inkjet printer paper is fine too. The point of all this is it gives me a convenient surface I can draw marking out lines, scribble and jot notes on without marking the board beneath.

Some time is spent placing the components of the steam plant on the base board and then moving them around until I'm happy. If this bit goes here will I have enough room for that bit there? Can I reach a valve without buring my fingers on an adjacent steam pipe? Will there be enough room for everything? Pipecleaners are a cheap and easy way of simulating pipework. Tin cans, blocks of wood, and bits of tube can all be used in place of components yet to be built.

Back to building a steam plant…

The Bix 009 burner has been installed in the firebox and tuned in accordance with the comprehensive instructions that came with it. You can buy Bix burners here – **LINK** (Shameless plug! )

The boiler has been test steamed. It works! Yay!

The boiler was then temporarily connected to an MSM Tyne marine plant for further testing. Since it ran the Tyne engine in a satisfactory manner I felt more confident about this project. (Well there are always those nagging doubts… Will the boiler be big enough? Will it make enough steam?)

Using the procedures detailed in the previous post, the VR1A has finally been connected to the boiler.

The engine is mounted on a block of wood to give clearance for the flywheel.

Between the engine and the block of wood there is some aluminum sheet. This prevents the engine becoming stuck to any varnish or paint that will be used on the block. (Been there. Done that. Had to use a gas torch…)

A T piece has been fitted at the steam outlet from the boiler so orphan engines can be run in future.

Thank you. I'm glad you are enjoying it.

Now that I know the steam plant works it is time to make the other components – a water tank and a condenser. The condenser seen in the video on Page 1 is just a temporary device that I often use to prevent oily cack and steam spraying on to my work bench.

I have a PMR water tank kit. This is what comes in the box…

I intend to make a slightly different 1/4" x 40tpi bush so I can have a valve on the water tank.