Repacking OxyFuel Torch Valves--Substitute for Graphited Asbestos?

[jackw19]

What's the right material to use for re-packing valve stems in vintage oxy-fuel torches? Back in the day I expect graphited asbestos cord would have been the material of choice, but short of a trip to India or China I think that'll be a little hard to come by.

I do understand that cleanliness is next to Godliness and that one could well meet the creator face to face in the presence of oil or grease. It is possible to find PTFE valve packing cord that's rated for oxygen service, but the smallest I've been able to locate is 0.125" diameter. That's just too big for the aircraft torches I'm restoring.

Some forum members have mentioned machining PTFE bushings for this purpose. That'd work, but the necessity in some cases to split the bushing in order to install it over the valve stem threads makes that solution somewhat less attractive. The same consideration would apply to a square profile PTFE O-rings, even if such could be located in the required grade and sizes.

Maybe fiberglass string and litharge?

Thanks.

[FlaJoe]

Maybe fiberglass string and litharge?

Can you even buy litharge anymore? I haven't seen any for years.

"I expect graphited asbestos cord would have been the material of choice, but short of a trip to India or China I think that'll be a little hard to come by".

I don't know if this material is acceptable or not but I wondered if you checked Flea-Bay? Anything and everything seems to be available from China via them.

" It is possible to find PTFE valve packing cord that's rated for oxygen service, but the smallest I've been able to locate is 0.125" diameter. That's just too big for the aircraft torches I'm restoring."

I don't know if it would work but can you use teflon tape for packing or will it leak? I just bought five rolls of US made oxy-grade tape from Flea-bay for a very reasonable price.

[jackw19]

FlaJoe, I'll bet you're right. Litharge probably means another trip to China.

Thanks for the tip re oxy-tape. Enough times around the mulberry bush just might work. Test w/ argon.

[Jax]

I was hopeing to see a lot of knowledgeable feed back on this because I have a torch that knobs are real hard to turn. I have a roll of graphite impregnated string sold to repack plumbing valves. I picked it up at plumbing supply about 5 years ago. The dia is about 0.125 ,same as you found. Mine has 5 smaller cords twisted togeather which are easy to separate when a small cord is needed. I always figured the cord was cotton but could be asbestos for all I know. Regarding Teflon tape,they sell Teflon packing string anywhere plumbing supplies are sold,I've even saw it at Lowes and Home Depot. I wasn't sure if any of those should be used so hopfully wiser people will chime in. While on the subject,is 100% silicon grease not to be used with compressed gas aperatuses?

[Dana gear]

Victor equipment uses oxygen safe Teflon on valve stems for sealing.
www.sealseat.com supplies most of the parts to gas apprentice rebuilders, and I believe will sell to end-user's.
There going to offer replacement valves for quite a few different brands.

[walker]

I use cardboard. Simply put the torch in a box and send it to regulatortorchrepair.com. Excellent folks to deal with, very reasonable pricing. The stuff works and looks like new when you get it back.