What washer for use in fermenter?

[dreaddan]

So I've ordered a thermowell, which has turned up with no washers or backnut
I can get a 1/2 brass backnut from screfix quite easily but what washers can I use that I can get easily for use in my fermenter?
Looks like it's either rubber or fiber
Thanks

 

[dcbrookes]

Dowty type washers are best for sealing anything of this type, but the stainless ones are very expensive. I have used the plated steel ones on my kegs but only on the outside. There are plenty of sellers offering Dowty washers on Ebay.

 

[LeeH]

An o ring will also work. A stainless lock nut is a better option unless you like lead in your beer.

 

[Davy6Mac]

I personally would use silicon washer/O ring, because it's suitable for food grade/products.
A stainless steel locknut is the better option as well

 

[dreaddan]

Cheers ill have a look at these

Are the lock nuts food safe?

 

[Bigdiggers]

These washers should fit

https://www.themaltmiller.co.uk/product/12-bsp-stainless-steel-washer/
these nuts definitely do

https://www.amazon.co.uk/gp/product/B07BKTBGVL/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

[dreaddan]

Thanks.