On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

I'm 99% sure that Boss White is rated for potable water, but surely it
will say so on the tin or tube.

Traditionally Boss White was used with hemp (although it can be used alone).

These days I tend to use the various PTFE-based thread sealants
available from SF and TS (but seldom have issues for potable water so
don't usually worry about that). Less messy and easier to dismantle than
Boss White type products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.