Seeping threaded fittings... *stainless/brass plastic*

[Deuce]

Hi all, just joined to try and get a definitive answer on this!

When connecting threaded fittings, metal of plastic, what single application thread seal product works best?

We have tried:

• PTFE + silicone. Virtually always seals but will seep if agitated after cured.

• PTFE with Fernox general purpose thread sealant, still sometimes seeps on larger threads 1" or over, and can also fail if agitated after cured.

And also just silicone on some ABS/PVC threaded fitting, as advised by the manufacturer (PTFE can react apparently).

We have to quite often adjust the layout of the kit we assemble and we need to be able to make and break threaded connections relatively quickly, cleanly and not waste time re-working seals as we currently do sometimes. We use threads up to 2" max.

Cost of solution is really not an issue as it's having way more impact on time than we can afford as it is. We also need to be really confident our kit will not leak/seep at all.

I have been looking at Loctite 5776 (LOCTITE 5776 - Thread Sealant - Loctite) and wondered if anyone here had used it, or similar, or could reccomend another product.

I guess as it's so important we don't get leaks, products used reliably for gas might prove most appropriate?

Many thanks in advance

David

 

[ShaunCorbs]

577 is great but won't work on anything plastic

Sounds like you need loctite 55 or boss white and hemp

 

[Chalked]

As Shaun says . Don't use 577 on plastic! It ONLY works with metal.

 

[Deuce]

Thanks both of you.

How reliable/foolproof is 577 generally? For example silicone smoothed into first few threads is normally extremely reliable, initially. But it's not reliable long term. So we need a high tech product that seals as reliably but also copes better with a little movement over time. Can't use a thread 'lock' product though as we do need to be able to break the connections sometimes..

 

[ShaunCorbs]

Never had a leak and you can disassemble when you need to

 

[Deuce]

Have you used on threads up to 2"? And I assume just the 577, no other products used alongside it?

 

[ShaunCorbs]

Yep and straight medium non tapered pipe

Even done an pita 4" one that was in a floor

Follow the spec tho eg need to clean the cutting oil off before you apply it

 

[Last Plumber]

Hi all, just joined to try and get a definitive answer on this!

When connecting threaded fittings, metal of plastic, what single application thread seal product works best?

We have tried:

• PTFE + silicone. Virtually always seals but will seep if agitated after cured.

• PTFE with Fernox general purpose thread sealant, still sometimes seeps on larger threads 1" or over, and can also fail if agitated after cured.

And also just silicone on some ABS/PVC threaded fitting, as advised by the manufacturer (PTFE can react apparently).

We have to quite often adjust the layout of the kit we assemble and we need to be able to make and break threaded connections relatively quickly, cleanly and not waste time re-working seals as we currently do sometimes. We use threads up to 2" max.

Cost of solution is really not an issue as it's having way more impact on time than we can afford as it is. We also need to be really confident our kit will not leak/seep at all.

I have been looking at Loctite 5776 (LOCTITE 5776 - Thread Sealant - Loctite) and wondered if anyone here had used it, or similar, or could reccomend another product.

I guess as it's so important we don't get leaks, products used reliably for gas might prove most appropriate?

Many thanks in advance

David

I take it this is a threaded joint?
What are you putting together?

 

[Deuce]

Yep and straight medium non tapered pipe

Even done an pita 4" one that was in a floor

Follow the spec tho eg need to clean the cutting oil off before you apply it

That's very reassuring to hear! I'll get it ordered.

Yes we clean the fittings, we use loctite spray cleaner.

Thank you so much for the help

 

[Best]

Don't use actual Boss White on anything plastic. It is oil based and will react with most plastics and destroy it