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.........
Full Roast, Gold Blend.......And started to turn it into a former, for the new displacer. Messy stuff.........
Full Roast, Gold Blend.......Finished article.........
Full Roast, Gold Blend.......Wrapped tinplate around, and soldered the overlap..........
Full Roast, Gold Blend.......Two off, 3mm thick end discs. Thinned to 1mm, where possible........
Full Roast, Gold Blend.......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.......
Full Roast, Gold Blend.......Then rolled the tin over the end cap, and tidied up with a gentle touch on the grinder.........
Full Roast, Gold Blend.......Internal boss for the 4mm threaded displacer shaft.......
Full Roast, Gold Blend.......Held with 2off M2 grubscrews, and hi temp sleevelock........
Full Roast, Gold Blend.......The assembly spins true, within half a mm. Close enough........
Full Roast, Gold Blend.......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........
Full Roast, Gold Blend.......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.......

Full Roast, Gold Blend.......David D