[modeleng] Is piston rings : Was Lack of mail - just testing

Partly so that Mike doesn't feel too lonely ... ;-)

As I am finally back on line (curtesy of a new modem!) a question for all of 
you steam engine experts ... I have been asked to make a model steam engine 
out of wood, for demonstrating their operation with. Whilst there is to be a 
"boiler", propulsion will be via compressed air, most likely an electric car 
tyre pump, by the way, so there definitely and deliberately won't be any 
temperature problems to burn any fingers, let alone set fire to it all!

As it will be all wooden construction, there will be some small movement due 
to humidit and temperature fluctuations, more than likely, and so I am 
worried about how to ensure a permanent seal between the piston and the 
cylinder walls, as metal piston rings would only move with temperature 
changes, and then not to any noticeable amount. I had thought about using 
neoprene O-rings, tight fitting enough to still form a seal if it all 
slackens up a bit, but can anyone recommend anything better please? I had 
also thought about greased hemp or even string, but would I need to knot it, 
with the knot then causing an obstruction, for instance.

With thanks in anticpation,

TonyW.

MODEL ENGINEERING DISCUSSION LIST.

To UNSUBSCRIBE from this list, send a blank email to, 
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.

Other related posts: