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

If using graphite cord, the 'cord' is made up of thinner
cords twisted to make a thicker one.  When I used it for
the PM1 piston (the ring groove(s) was not cut to specs)
I just wrapped it around several times, tucked it into
ring groove so that it just peeked outside/above it and
squeezed the whole mess into the cylinder.  With the cord
it was a tight but reasonable fit.  Reassembled it, tried
it on air (yes!) and then steam.

If using it on an item without a ring groove I've found the
teflon tape to work best.  I used it on the gland nuts on
both of my small PM engines, a #3 and #7, with success. 
It is a bit of a balancing act to get it all right.

Wayne

I noticed if I tighten down my gland nut, the piston can barely move… is this because it presses the gland packing down around the piston rod too tightly?