Cylinder packing question

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Peter H1956
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Cylinder packing question

Post by Peter H1956 » Fri Jun 30, 2023 2:04 pm

After my engine runs for awhile I get some leakage from the packing. Not allot , but I wonder if this is normal with steam engines. The engine is a Hasbrouck#1 and I am using tefpack shaft packing with PTFE. Can anyone recommend a packing that they like?
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barts
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Re: Cylinder packing question

Post by barts » Fri Jun 30, 2023 3:12 pm

I've had excellent luck with simple thin PTFE faucet packing on Otter's engine. Yes, a bit of tightening is sometimes required as things warm and settle in. Keep in mind that PTFE packings are much more "plastic" than traditional graphite flax and the like; the PTFE seems to flow into any air spaces over time, reducing the sealing effect. After some time, this disappears and the packing remains tight until renewed or disassembled. Tighten gently; PTFE does not need a lot of pressurfe on the gland to seal.

I have a fresh roll of larger PTFE for Rainbow's engine which I need to install.

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Kelly Anderson
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Re: Cylinder packing question

Post by Kelly Anderson » Sat Jul 01, 2023 3:47 am

When I can, I will make a bushing of virgin Teflon on the lathe, and disassemble the rod as needed to install it, and forget about rope packing.

As Bert says, virtually every packing gland needs to be tightened from time to time. If yours is constantly in need of being tightened, some things to look for would be:
1. Perhaps the piston rod is tapered, leaving a gap between the packing and the rod at one end of the stroke.
2. Perhaps the rod has a rough surface. BTW, stainless steel is prone to galling and tearing up the packing. Monel is a much better choice. It self polishes against the packing to a mirror finish.
3. Perhaps the crosshead is out of line with the piston, causing the rod to move sideways a few thousandths as it travels through the packing, stretching the hole in the packing away from the rod.
4. Perhaps the packing nut is simply backing off when the engine is operating.
Last edited by Kelly Anderson on Sun Jul 02, 2023 10:48 pm, edited 1 time in total.
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TahoeSteam
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Re: Cylinder packing question

Post by TahoeSteam » Sun Jul 02, 2023 2:55 pm

Many factors involved, as stated above.

Have you been 'stroking the limbs of the dragon' (lubricating the piston and valve rods)? A mixture of steam cylinder oil and graphite applied with your sibling's toothbrush or an old antisieze brush will do the trick for lubricant.
Peter H1956
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Re: Cylinder packing question

Post by Peter H1956 » Sun Jul 02, 2023 6:57 pm

I have not been lubing the piston rod. I will be now. Thanks
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