O-rings on drain plugs

marshg246 · Feb 9, 2022

Stephen Hill said:
I usually think of a Dowty seal as a single use item. Particularly when I am using them on fuel taps.

There are many types of British Dowty washers. Two are Steel and Aluminum, of course, both with rubber of some sort. I'm not a metallurgist but I assume that the aluminum ones seal using both the rubber and metal and the steel, rubber only. Here's probably more than you'll ever want to know about them: http://www.potterassoc.com/pdf/bonded_seal_information_and_sizing_chart.pdf

The US stat-o-seals are similar in varity.

So, I'm sure some are not reusable, and some are. The ones I use on petcocks might be reusable, but I have never tried so I don't know - I hate petcock leaks!

L.A.B. · Feb 9, 2022

Stephen Hill said:
A dowty style washer was standard issue for the gas taps.

Not arguing over their use but the copper/rubber crush washers aren't Dowty seals and I use those copper/rubber crush washers.

The aluminium/rubber bonded crush washers are Stat-O-Seals.
Dowty seals are generally steel/rubber and not crush washers.

Earl's Performance Products UK - Copper and Aluminium Washers, Dowty Seals, Stat-o-Seals

www.earls.co.uk

http://www.potterassoc.com/pdf/bonded_seal_information_and_sizing_chart.pdf

"The metal ring resists the bursting forces and limits the deformation of the elastomeric element."

concours · Feb 9, 2022

Stephen Hill said:
Misapplication? Tell that to the Triumph and Norton factories.
A dowty style washer was standard issue for the gas taps.
Here is the original style: https://www.baxtercycle.com/product/70-7351b/
Or you could use a more modern style:

Triumph, Norton, BSA, Petcock and Tachometer Housing Bonded O-Ring Washer

Sealing washer for tachometer and petcocks on Triumph, BSA and Norton models

www.mapcycle.com

Same difference. It is actually brilliant engineering, as it seals on three faces, including the threads. And will let you tweak the angle of the petcock without leaking.

Thread sealant is a better example of misapplication!!
It's main purpose is thread lubrication on large diameter coarse thread tapered pipe joints.
"LOCTITE® 567™ High Temperature Thread Sealant with PTFE is a general purpose instant thread sealant for taper/taper threads and fittings."

I won't tell the entire vintage brit bike industry they are wrong. Clearly they work, somewhat. Please. don't do what I do/suggest, I'm a newbie, and it's JMWO. Cheers

Stephen Hill · Feb 9, 2022

Looks like "dowty seals" now come in a variety of configurations these days. Or folks just use the name loosely.
Some have crushable metal shells, some solid, etc. The current language is composite or bonded sealing washers.
Lots of info here. https://www.parker.com/Literature/Praedifa/Catalogs/Catalog_CompSealingWashers_PTD3358-EN.pdf

O-rings on drain plugs

marshg246

L.A.B.

Moderator

Earl's Performance Products UK - Copper and Aluminium Washers, Dowty Seals, Stat-o-Seals

concours

Triumph, Norton, BSA, Petcock and Tachometer Housing Bonded O-Ring Washer

Stephen Hill

Similar threads