I have a couple of full size boiler water gauges for my steam launch that have cocks that need repacking. These are not a taper cock, the moving part is a parallel cylinder. The fixed part has a cylindrical hole with four dovetail slots along the length of it. These are filled with packing, and there is a ring of packing around each end. This is put under compression by the retaing ring and plug that go in each end. I've attached a picture of the parts in my album. That one is a blowdown cock, but the steam and water cocks built into the gauge fittings use the same construction. The other blowdown cock is a Klinger type, and uses a cylindrical packing that I was able to replace from a local supplier.

I removed the old packing, partly because it had gone very hard, and partly because it is probably asbestos based. (OK, I disposed of it carefully.) So what should I use to repack them? Heritage Steam recommended some graphite ribbon, but that does not seem to work, it breaks up when you pack it into the slots and bits of it fall out the steam/water holes once the cock is assembled. It seems to need something more fibrous. Does anyone know of anything suitable? There used to be fibrous packing that was based on hemp or the like, but nobody seems to know anything about that sort of thing. Somebody in the preservation movement must have done this before.

John

Edited By John Olsen on 09/03/2018 04:28:27

The stuff I have is this one **LINK**

I wonder if I would be better with the woven teflon stem packing, maybe mixed up with some graphite.

I think A & T Burt have gone the way of the Moa. I have talked to various suppliers in Hamilton, but no useful suggestions so far. Mind you, I am finding that people like Asmuss can't even supply stuff that is listed in their catalogue and supposedly in stock in their computer. I'm trying to get suitable steam rated fittings and a globe valve for my main steam line, it has been over a week and they have not managed to get them down from their stock in Auckland. Meanwhile John Deere can get me parts for an obsolete lawn tractor within 24 hours from Melbourne in Oz

John

I've found a way of doing it. You take 6 lengths of ordinary teflon tape, and twist them into a strand. Repeat two more times, then plait the strands into a braid. Press together so the stuff sticks to itself. Cut into lengths about half as long again as the slots in the body. Press into place with a small round thing, I used a pin punch, using the side to press the braid into the dovetails. Put the cock part in and put one end plug in place temporarily. Use the end of the pin punch to press the excess into the ends of the dovetail on the other end. Fit a ring of teflon tape into that end, remove the other plug and repeat. Try it under pressure and if it weeps, add more packing under each plug and retighten. The stuff packs down quite a lot. Hasn't been tried under steam yet, but they are holding water pressure at up to 300 psi. (They don't have the glasses in yet, just a piece of stainless the same diameter for test purposes.)

John