I’ve been looking at how to make the copper boiler tubes. For the vertical boiler I’m using a piece of 15mm household plumbers pipe. For the miniature traction engine I’m working on I wanted a lot more smaller pipes.
I was looking around and scratching my head to think of places that I could purchase copper tubing that would be appropriate for this small boiler that I’m making.
The boiler is just 1.75 inches in diameter and just 140mm long (sorry for the mix of units). This means that the pipes through the boiler need to be small.
This pipe is just perfect at 3/16 inch and 22swg.
The tube is marked along it’s length with the metric dimensions of 4.74mm diameter and 0.7mm wall thickness.
Not exactly the same as the imperial size written on the package, but measuring the tube with a digital caliper shows it as 3/16inch.
The problem with this coiled tubing is that when you uncoil it it’s not very straight.
A hard flat surface, a flat board and the tube being rolled back and forth.
Roll the pipe firmly back and forth and it straightens out.
The copper endplates formed over a mandrel and with the back edge machined to shape.
I’ve written a separate page explaining how to anneal the copper and form these plates.
These particular plates are just domed and I will drill the holes later.
The copper boiler tubes all cleaned up, straight and with the ends trimmed.
I stuck masking tape over the endplates first so that I could carefully draw onto them.
I have an engineers square set with a centering attachment. I used the centre and a line across the centre to work from.