Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Did this 5mm ID x 7mm OD x 1mm work?  Did you find a good source / part number?  Also what is "Using Rog's method (for cast base Empires)" - I'd love to read that.

I found these at Granger

O-Ring: 5 mm Nominal Inside Dia., 7 mm Nominal Outside Dia., 7 mm Actual Outside Dia., Black, 25 PK
-15 Degrees to 400 Degrees F
Item # 1RHN2
Mfr. Model # 1RHN2
UNSPSC # 31181506
Catalog Page # 2176