Thanks for your kind comments, Chaps!
Steve. I cannot find anything about, fused glass foam.......

Hmmm...... Almost a month gone, already!

Not had much workshop time, recently. Just a few minutes, here and there......

I made up a bundle of offcuts, to give a 4" square cube.........

And started to turn it into a former, for the new displacer. Messy stuff.........

Finished article.........

Wrapped tinplate around, and soldered the overlap..........

Two off, 3mm thick end discs. Thinned to 1mm, where possible........

The wooden former, held the disc square to the tube, while I drilled for 6off 1.5mm dia rivets
Natural ingredients only, for my engines.......

Then rolled the tin over the end cap, and tidied up with a gentle touch on the grinder.........

Internal boss for the 4mm threaded displacer shaft.......

Held with 2off M2 grubscrews, and hi temp sleevelock........

The assembly spins true, within half a mm. Close enough........

Initial runs, on twin candles were disappointing.
The hollow displacer sounds to be grinding/ grating as it slides through it's bush. Not a coffee table engine any more!
The new displacer weighs 94grms. The original one weighed 69gms, after toasting. The extra weight caused a hesitation, getting over TDC.
So I added 3 extra, 2" x 1/2" x 1/8" weights to the flywheel........

Didn't make any difference!

So, I tried with my temporary meths burner, and it ran happily. Well balanced, even up to blurred revs.

I feel another stainless steel burner coming on.......


David D