tools, materials & knowledge for model makers
It is always exciting to see builds of our engine plans, this one especially so as it will be the oscillating engine on steam. Up until now I have only run this engine on compressed air. This build is by Michael Prady and this is a great mix of original design, changes in materials and … Read more
My original boiler heat loss test object was a round disc of mild steel and copper. However, this doesn’t relate that well to the actual boiler. This is so that I can test different types of boiler insulation and multi-layer insulation. My original idea for measuring the thermal insulation for the boiler was to make a … Read more
Looking at the thermal insulation of a boiler and just how thin I could make an insulator I started looking at Multi-Layer Insulation or MLI’s. The effective thermal conductivity of an MLI is in the order of 10-5 Wm-1K-1 as given by Sutheesh and Chollackal [ref 1]. The thermal insulation I achieved for the vertical boiler … Read more
After a few measurements on the vertical boiler, using the cooling curve to estimate heat loss, I achieved a reasonable level of thermal insulation. However, can I turn this into a more methodical approach in the home workshop? I can electrically heat a block of metal, it would be best if this was copper. Copper would … Read more
The saddle and the Burrell boiler have been on the bench for a while. Most of the delay was down to me struggling with the design and location of the steam valve. The Saddle The saddle was designed to allow me to split the cylinder and ports to make it all easier to make. This … Read more
A few silver solder coupon tests to look at options for soldering copper and phosphor bronze (PB). The test parts are a representation of the PB saddle and copper boiler on the miniature traction engine. Preparing Test Parts Fundamentally a sheet of copper 1.2mm thick has a PB M4 bolt through the top and into … Read more
Vertical vs Horizontal Steam Boiler, what is the difference? I made a vertical boiler as a test piece before making a horizontal boiler. Was that sensible and did it prove anything? I did learn the basic requirements of making and testing a boiler. I also learnt about fireboxes and how to get heat into the … Read more
This won’t be the last, but optimising the firebox and burner has moved the boiler to a place where it can deliver steam to a steam engine. This has involved a number of changes to the system. Some backed up with data, some just good engineering. Burner Wick This now uses a ceramic matting for … Read more
One thing that has concerned me is what is the optimal Flame to Boiler Distance? The original firebox and methylated spirit burner was generating approximately 54W. At the operating point of the boiler at 40psi and 140°C the losses are 35W. So, there was not that much headroom for adding more water or taking a … Read more
Making a fire grate from a solid piece of cast iron. I wasn’t going to be able to buy one of these and I don’t have the kit to cast one. So, my only option was to machine from from cast iron. Cast iron disc 42mm in diameter and 8.5mm thick. This fits perfectly into … Read more