# Threading stainless steel



## shereenp (Oct 30, 2012)

At this job were at we are doing a whole **** load of process piping and the dumb ass engineer decided to use stainless for reverse osmosis for the most part. And some runs will carry nitric acid. We determined you need a high speed high temp threading oil, and special dies , however the pipe dope we've been using isn't sufficient. Just regular **** , with Teflon. So we called up the guy at pinacle , stainless distributor, and told us he has had much luck with copper coating compound. So far so good, but were curious to know if there's anything better out there that might save us from leaks or cracking of the fittings because of stainless reaction from metal to metal. First time using stainless and it's been a hell of an experience . Any suggestions or tips on threading stainless and it's be much appreciated.


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## shereenp (Oct 30, 2012)

Also if anyone knows of a compound that is compatible with acid. We learned copper coating is no good. Thanks


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## Redwood (Sep 8, 2008)

304, 316, Carpenter 20?

What acids? nitric only?


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## U666A (Dec 11, 2010)

I've had to use a rheostat before to stop the dies from tearing the crowns off the threads when working with 304...


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## Redwood (Sep 8, 2008)

A good thread cutting oil designed for stainless is important for threading stainless steel... :laughing:

Without it the life of the dies will be shortened and galling of the threads is almost guaranteed....

As U666A stated a rheostat may help...
Metal turning is all about speeds and feeds, so when tough metals are being used speed control can be critical for success.

I was lucky enough to have access to a lathe with the last stainless steel I threaded so I had all kinds of speed control.


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## shereenp (Oct 30, 2012)

Redwood said:


> 304, 316, Carpenter 20?
> 
> What acids? nitric only?


304, and nitric only, but now sodium hydroxide is being talked about ...


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## Redwood (Sep 8, 2008)

shereenp said:


> 304, and nitric only, but now sodium hydroxide is being talked about ...


304 is fine with Sodium Hydroxide... :thumbup:

But...

Nitric Acid may be a problem depending on the level of concentration...

If the concentration is over 50% you may want to use 440 stainless steel...

The temperature of the solution may also have some bearing...


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## shereenp (Oct 30, 2012)

U666A said:


> I've had to use a rheostat before to stop the dies from tearing the crowns off the threads when working with 304...


Oh yes we've already screwed two sets of dies beaches we didn't have the right cutting oil? But now everything is good, threads cut super smooth. Now we're just wondering what a good sealing compound is that can be used for such a high friction rate, and compatible with nitric acid.


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## shereenp (Oct 30, 2012)

Redwood said:


> 304 is fine with Sodium Hydroxide... :thumbup:
> 
> But...
> 
> ...


Man 16 lengths of 304 have already been ordered and all the pipes cut , thread and installed. Haha, we have a dimwit for an engineer, and he thought PVC just wouldn't do the job, and I guess when your spending someone else's money, it's pretty easy to do carelessly ! Who needs stainless to carry water ?!? I mean come on!!!!


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## Redwood (Sep 8, 2008)

Tygon tubing would have been a great choice for any concentration of Nitric Acid...:laughing:

Cheap too!

PVC once again okay up to 50%....

Engineers are supposed to know this shiot....


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## MarkToo (Dec 17, 2011)

Why not use T-tape for stainless? It's a sort of silver grey colour. Works well.


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## Redwood (Sep 8, 2008)

Teflon Tape is fine with both Nitric Acid and Sodium Hydroxide...

Oops we are supposed to call it PTFE Tape...

DuPont is paying big bux to educate us in ads that Teflon is a Dupont owned trade name for PTFE - Polytetrafluoroethylene...

Dupont doesn't make teflon tape...:laughing:

Watch the ads show up now... Click them and make Nathan rich...:laughing:


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## MarkToo (Dec 17, 2011)

Redwood said:


> Oops we are supposed to call it PTFE Tape...


:thumbup:


I didn't use the T word. You however, are in big trouble mister.


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## 422 plumber (Jul 31, 2008)

There is a tape made for stainless. I can't tell you the brand name, but I have seen it at a coal burner.


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## MarkToo (Dec 17, 2011)

Here you go.


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## shereenp (Oct 30, 2012)

Redwood said:


> Tygon tubing would have been a great choice for any concentration of Nitric Acid...:laughing:
> 
> Cheap too!
> 
> ...


The guy did his engineering degree in china. No Canadian certification. Need I say more ... ?


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## shereenp (Oct 30, 2012)

Thanks for all the help Guys. Unfortunately we can't get a hold of the stainless ptfe tape, and a rheostat is out of the question. But at least ill be more readily prepared for the next stainless job if I'm ever stupid enough to accept it hahahah joking. Thanks again everybody


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## plbgbiz (Aug 27, 2010)

This is what we use on stainless threads.

We get it from: http://www.pipingalloys.com/


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## shereenp (Oct 30, 2012)

plbgbiz said:


> This is what we use on stainless threads.
> 
> We get it from: http://www.pipingalloys.com/


What are the components in that? Nickel and? Thanks


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## rjbphd (Feb 5, 2010)

RectroSeal won't work.....????


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## Redwood (Sep 8, 2008)

http://www.mcmaster.com/#pipe-thread-tape/=k0qjqr

As my regular tape I usually use the Std Mill Grade tape which is the equivalent of that blue tape some of the guys are using now... Been using it for years...


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## shereenp (Oct 30, 2012)

plbgbiz said:


> This is what we use on stainless threads.
> 
> We get it from: http://www.pipingalloys.com/


What are the components in that? Nickel and? Thanks


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## plbgbiz (Aug 27, 2010)

shereenp said:


> What are the components in that? Nickel and? Thanks


Specifically I don't know. It was recommended to me by piping alloys on a 2000 PSI washdown system install. I've been using it ever since.


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## plbgbiz (Aug 27, 2010)

rjbphd said:


> RectroSeal won't work.....????


We tried it and it leaked like a sieve.


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## rjbphd (Feb 5, 2010)

plbgbiz said:


> We tried it and it leaked like a sieve.


All the threads must've been cross threaded...laughing


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## rjbphd (Feb 5, 2010)

shereenp said:


> Thanks for all the help Guys. Unfortunately we can't get a hold of the stainless ptfe tape, and a rheostat is out of the question. But at least ill be more readily prepared for the next stainless job if I'm ever stupid enough to accept it hahahah joking. Thanks again everybody


 Okay, okay.. so the Rectumseal got throw out...what about exPANDO??


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## plbgbiz (Aug 27, 2010)

shereenp said:


> Thanks for all the help Guys. Unfortunately we can't get a hold of the stainless ptfe tape, and a rheostat is out of the question. But at least ill be more readily prepared for the next stainless job if I'm ever stupid enough to accept it hahahah joking. Thanks again everybody


Why can't you get it?

http://www.google.com/products/cata...&sa=X&ei=JO6WUPGNCqPEyQHXvIEg&ved=0CFQQ8wIwAA


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## shereenp (Oct 30, 2012)

plbgbiz said:


> Why can't you get it?
> 
> http://www.google.com/products/catalog?q=Nickel+ptfe+tape&hl=en&num=20&bav=on.2,or.r_gc.r_pw.&bpcl=37189454&biw=1024&bih=672&um=1&ie=UTF-8&cid=5953446813632980259&sa=X&ei=JO6WUPGNCqPEyQHXvIEg&ved=0CFQQ8wIwAA


We're in Yellowknife and for some silly reason , NWT wholesale doesnt carry "specialty" items such as stainless tape in their stock. I guess because there isn't much stainless work going on up here. the engineer didnt even know we needed a special oil let alone the tape...anyhow, we would have to order it and probs wouldn't show up for a week which is way past out deadline for this project


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## shereenp (Oct 30, 2012)

rjbphd said:


> RectroSeal won't work.....????


Never heard of rectroseal, what is it?


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## rjbphd (Feb 5, 2010)

shereenp said:


> Never heard of rectroseal, what is it?


 My favorite kind of pipe dope... number 5... they have other kind for their special purposes.. for real problem threads, I use Expando..


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## Redwood (Sep 8, 2008)

plbgbiz said:


> Why can't you get it?
> 
> http://www.google.com/products/cata...&sa=X&ei=JO6WUPGNCqPEyQHXvIEg&ved=0CFQQ8wIwAA


I get mine from McMaster overnight with standard delivery...:laughing:


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## MarkToo (Dec 17, 2011)

Redwood said:


> I get mine from McMaster overnight with standard delivery...:laughing:


Every supply house here has it plus all the other colours of the rainbow on the shelf...


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## Redwood (Sep 8, 2008)

shereenp said:


> We're in Yellowknife and for some silly reason , NWT wholesale doesnt carry "specialty" items such as stainless tape in their stock. I guess because there isn't much stainless work going on up here. the engineer didnt even know we needed a special oil let alone the tape...anyhow, we would have to order it and probs wouldn't show up for a week which is way past out deadline for this project


well then just use the super duper thick blue teflon tape and you'll be fine...


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## rjbphd (Feb 5, 2010)

I just googled Rectorseal.. I they have what you need for SS pipes..


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