Leaking Stainless Steel NPT Threads 1

[AMatthews]

Can anyone suggest a good pipe sealant to use to seal stainless steel NPT threads in higher temperature service (over 250C)? Currently use Silver Goop with poor results. Previously used Masters Metallic but it has been banned from our company due to lead.

 

[Darken99]

AMatthews,

What is in the pipes and what is the operating pressure?

I did a quick google and came up with this:

http://www.jetlube.com/NewFiles/tseal.html

Regards

 

[AMatthews]

The pipes contain hydrocarbons and the pressure is up to 600# flange rating. I am hoping for someone who has had some good experience with a particular sealant since the sales literature always promises great results.

 

[Darken99]

If you are referring to the Silver Goop from

http://www.swagelok.com/

It is not sealing because is it is a lubricant, not a sealant.

You may want to move this post to:

Piping & fluid mechanics engineering Forum

http://www.eng-tips.com/threadminder.cfm?pid=378

You will get more response in there.

Regards

 

[Xianglu]

I suggest to make a seal-weld to the threaded joints.

 

[unclesyd]

Here is an add on seal (TruSeal) we used quite extensively in a pilot plant that had all threaded pipe joints in lieu of welded fittings in a futile effort to save time and money.

http://www.millerfluidpower.com/pdf/TruSeal_02.pdf

 

[Cockroach]

Use a thread sealant or thread tape. Pay attention to your torque value for NPT threads, they easily pick-up.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[zuccus]

Threaded SS connections and your pushing the limits of the 600# flange? Something doesn't sound like it got put in right.

Zuccus

 

[reidh]

Like Cockroach said, over-tightening NPT threads can be just as bad or worse as under-tightening.

Megaloc made by Hercules Chemicals has worked for us in our low pressure application.

Reidh

 

[dimjim]

Might want to try this loctite site.

http://www.loctite.com/int_henkel/loctite_us/binarydata/pdf/lt3461.pdf