Diesel & silicon sealent?

[murdomack]

Hi Ted, Seastalkercat,

Teflon tape was a great invention but like all things it has it's downside. I mentioned earlier that good threads are more important than the sealant and the problem mentioned here is partly caused by people habitually rolling on too many layers of tape than what is needed.
When I was an apprentice, I can only remember the important bits its so long ago, we were told that two layers was more than enough.
I was recently working on an engine with a young Marine Engineer who had been told by his uncle, a Chartered Engineer, that he should apply seven layers. I explained to him that all the extra tape was preventing the threads from seating together and some of the tape would find its way inside the fitting with the diesel. I have seen him since and he says that he is following my advice with good results.
In the Petro-Chemical industry the tape is not allowed on some systems for similar reasons to that mentioned by Seastalker and also where there are finely calibrated instruments and valves

[marshmat]

Generally speaking, I consider the primary seal to be the job of the properly matched threads, with the one or two wraps of Teflon tape being there only to seal the tiny gaps that might or might not be left by the inevitable variations in thread machining tolerances. Excess sealing tape only gums things up later.

[Ben Machine]

Murdomack, could you advise a supplier of NPT fittings in the UK.
Cheers

[murdomack]

Originally Posted by Ben Machine

Murdomack, could you advise a supplier of NPT fittings in the UK.
Cheers

Hi Ben

I am away on holiday at the moment. I will send some names on Monday night. There are quite a lot in fact.

Murdo

[Ben Machine]

Thanks Murdo

[murdomack]

Hi Ben

Two boating online cataloques, www.aquafax.co.uk and www.asap-supplies.com have some npt versions of their fittings, phone and ask as they do not always have them in the online cataloques.
Try www.hydrasun.com, they are a hydraulic supplier but carry a lot of quality pipe fittings.

Try a search for "npt pipe suppliers" on a UK site (say www.virginmedia.com) that alows a UK only search. You will get a lot of leads from this, I've added two here,
www.nero.co.uk
www.waverleybrownall.co.uk

If you are still struggling why not order from the US, www.mcmaster.com have a great onlne cataloque and will send worldwide. I have used them many times. If the order is small it probably won't attract the Customs taxes, but the prices are good even if you have to pay the extra.

Murdo

[Ben Machine]

Murdo
Thanks for the information I think I have found what I neeed at Hydrasun.
Cheers
BM