It looks like Hallite is a UK Co with website, contact phone numbers and on-line expert chat…and google throws up stockists..

https://hallite.com/

Like wise have used Hallite seals in the dim and distance past, but don’t remember Hallite washers. Having done a web search seams there is Halite washers, note one l. These appear to be from gasket material referenced a few times on my search as used on Lambretta joint faces. So perhaps not a flexible seal material as such.

Hallite seems to have disappeared, I needed [wanted] some a short while back but ended up using an alternative from Ebay — enter Hallite Gasket Material and search you should find something suitable to make your washers from – easy enough to make a couple of one use punches from the scrap box.

My recollection of Hallite is it was a paper based material with graphite impregnated and some form of reinforcement but I don't remember it as wire ? Stand to be corrected of course.

John

Used to be able to buy this in a rolled up sheet which was about 1/32 thick have used this in the past for seals on steam boilers may have some ofcuts still as left overs will have to look what i have if any interest , years since i bought any..

Regards Brian

Like NDIY, I wondered if Dowty washers would do the job. Depends on the rubber insert having a high enough temperature capability.

You could make your own washers, by punching out from a sheet of gasket material. Punch the hole first, and then the OD!

Howard

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… I expect Dowty would be pleased to see that  ‘generic’ bonded seals are  not being marketed under their trade name.

MichaelG.

Edited By Michael Gilligan on 12/07/2020 08:31:38

Bonded seals/ Dowty washers are used to seal banjo type fittings on hydraulic systems, a particularly specialised function.
Dave W

There really is no need for the washers but I presume that you have made the parts to the drawings so the gap for the O ring will be too big for the O ring alone. Your PTFE should be fine to make the washers or you could just make a spacer washer out of brass (put on the boiler side of the O ring) to make the gap the right width for the O ring on it's own.

I've used the O ring seal on several locos and it works very well. Much better than the threaded joints beloved by LBSC which are an absolute pain!

John