Composite washers for Bullfinch and Sievert propane torches

I have both Bullfinch and Sievert torches. The screwed joint between torch handle and extension tubes are sealed by means of what appears to be some sort of fibre washer. These have become worn over time and I am getting gas leaks from them. I have looked on the Bullfinch and Sievert websites, but they don't appear to be listed as spares.

Does anyone know what these "washers" are made of. I do have some thin rubber sheet that would do at a pinch. But I may as well use the correct material if I can find out what it is?

Thanks,

Andrew.

Edited By Andrew Tinsley on 14/11/2020 15:09:33

I found these on a search:

**LINK**

Brian

Good to see Bullfinch are still on the same site.

CuP Alloys list the Sievert washers, £7 for two, if you want the genuine article. I just sourced a pair as one of my burners was missing the washer entirely!

IIRC they used to be lead but the current ones certainly aren't and looked to be from 1/16th gasket/jointing if you have that thickness handy.

Mike

Thanks all, I didn't see the washer on the Bullfinch site, although it doesn't seem they are a regular spare. At £7 for two Sievert washers I would expect them to be at least gold plated!

I do have some thick rubberised gasket material come to think about it. I will use some of that. Thanks everyone for your suggestions, much appreciated.

Andrew.

I've not played with Bullfinch stuff much, but I'm an expert in burning my hand on the Sievert nozzle.

So I can assure you that the nozzle gets hot. Very hot. Oxide dis-colouring hot.

Upon which basis I doubt that a rubber washer is going to cut the mustard (hot or otherwise).

I've also had experience (albeit not to an expert level) on having the nozzle come loose on the neck, and the whole thing breaking out in a ball of flame. Which is exciting but not useful. That's why I grabbed the nozzle to tighten it, and regretted it shortly afterwards and for some time thereafter.

My impression is that the Sievert washers are lead or possibly some kind of graphite material.

Seven quid a pair? Bargain of the week!

Stay safe (or is it too late?)

Simon

edited for minor typo

Edited By Simon Williams 3 on 15/11/2020 00:22:48

Ummmm....

I should be more careful to say exactly what I mean.

I do not believe Andrew's rubberised gasket material will be at all suitable. When I said gasket/jointing, I meant the material that is used for joints on steam engines for the likes of cylinder covers. To be clear, I'm talking full-size, not model. I very much doubt the average model engineer has much use for 1/16" steam jointing.The washers I bought appear to be from something like this, although it is impossible to be certain of the exact grade.

Given that the washers used to be lead, years ago, I wonder if a more accessible route would be to cut them from offcuts of lead flashing. I would think a couple of tubular mild steel punches would suffice for this, without any need for hardening unless going into production.

Mike

Thanks again,

The washers I am talking of go between the torch handle and the extension tube, which goes to the burner itself. There are NO washers between tube and burner unit. So the washers will be operating in a cool region. Rubber would be fine in this position. but not as hard wearing as 1/16 gasket material, which I also have. If all else fails, I can go the lead flashing route. I have lots of that left over from a major extension project.

Abndrew.

Silicon rubber withstands i/c glow engine exhaust, but that's tubing.

I am confused!

My sievert torch is a pro 86. The washers fit between the burner and neck tube. The burners concerned are 3938 - 41 and 2941 - 44. These are the ones sold by CuP so they are not suitable for you - even gold plated!

There isn't a washer between handle and neck tube. You will get a gas leak here if the connection is not nipped up tight.

I share Simon's experience when changing burners during demonstrations of sievert torches. I did learn eventually!

Sorry that I can't be of more help.

Keith

I'm with Keith.

Could Andrew put a photo of the bits up for us, we must be talking at cross purposes here.

Rgds Simon

My Bullfinch equipment is about 50 years old. All 6 burners and the extension tube came with sealing washers in the female threads. These washers appear to be CAF. They do need a good tweak to make sure that they're sealed, esp. the smaller burners.

I've never needed to replace a washer, but it would have to be a different material nowadays of course.

I've not seen a lead washer for this application, but the graphte-like coating on the CAF does give it rather leaden appearance.

Add; I realise the Sievert extension doesn't have the same type on connecting joint.

Edited By Clive Brown 1 on 15/11/2020 13:50:06

I have several Sievert Propane blowlamps, the older handles have a 10 x 1 thread to take the neck tube, the newer ones have a 3/8 BSP RH thread for the neck tube The neck tubes have a hemispherical end which seals against the cone within the handle. No gasket is used. If there is a leak one or both of the mating surfaces is marked or the neck tube captive nut has not been tightened sufficiently.

This method is exactly as used on oxy/fuel gas lamps for the hose tails at the regulator and at the blowpipe.

The burners do have a gasket where they seal against the neck tube but I cannot say what the gasket is made of.

HTH

Dave