Need help with stainless tank tee setup

[DStyduhar]

Hi guys,

Have one of those Boshart stainless tank tee setups with the union. How do I adapt the stainless to the copper piping without corrosion occurring? I know some folks say dielectric union but I'm not sold on that. Not to mention I can only find galvanized/copper versions.

Basically I'm trying to adapt from 1-1/4"female SS thread to 1" copper pipe. What about a 1-1/4"F to 1"F schedule 80 pvc bushing? And then a 1" male to 1" sweat copper fitting threaded into that?

Thanks for any advice.

Drew

 

[Valveman]

Galvanized will be eaten out quickly when screwed to brass, SS, or copper. But never had any problems with brass into Stainless. The PVC bushing will work, but I don't think it is necessary.

 

[Sponsor]

 

[Reach4]

Idea regarding your concern about galvanic corrosion: http://www.designbyinitiative.com/files/8514/2711/8760/Galvanic_Table.pdf is one of the galvanic tables. Two different electrodes in an electrolyte should give a voltage corresponding to the difference in electronegativity. The bigger the difference, the more galvanic corrosion.

Suppose you put some of your copper and your stainless tank tee partially into a plastic bucket with some electrolyte, such as a vinegar solution. Use your multimeter to read how many millivolts difference you get. The smaller the difference, the less galvanic corrosion.

Usually brass and stainless are close enough to not worry. Stainless varies.

 

[DStyduhar]

Yeah I'm sure this stuff is cheap Chinese stainless....304 grade.

You know whats interesting though.....how close brass and copper are. I have heard you should not connect stainless to copper but brass can work.

 

[Reach4]

Yeah I'm sure this stuff is cheap Chinese stainless....304 grade.

https://www.rcworst.com/BII-07ST-13-2U-Stainless-Steel-Union-Tank-Tee-With-PTFE-Seal-1-25-MPT-x-1-FPT-13-Center-p2183.html confirms 304.

Your tank tee may have a 1 inch female and 1-1/4 male thread. You could put a 1 inch EP pex fitting into the tank tee, and do part of the run in 1-inch pex. People avoid the plastic female threads.

 

[DStyduhar]

I have heard about avoiding female threads but usually its sch 40 stuff and also its a bell end. Unless I'm mistaken, the issue is when tightened the female portion expands and wont seal....possibly cracking. Is this true?

My plan was to use a sch 80 bushing where the male threads are tightened into a stainless ball valve. Seems like this would prevent it from expanding but who knows. I'll have a backup plan haha.

 

[Reach4]

I have heard about avoiding female threads but usually its sch 40 stuff and also its a bell end. Unless I'm mistaken, the issue is when tightened the female portion expands and wont seal....possibly cracking. Is this true?

On threaded well drop pipe, the pipe is usually schedule 80, and the coupling is schedule 120. Plus the well person has to be more careful to not overtighten vs using stainless couplings.

https://terrylove.com/forums/index.php?threads/drop-pipe-choice-with-new-pump.53385/#post-389198

There is another consideration. Newer plumbing codes seem to not allow PVC pipe indoors. I suspect there is some kind of defacto exception for stuff around the pressure tank. I don't know if this would apply to pvc fittings also. So murky IMO.

 

[DStyduhar]

gotcha.

Here is another wacky idea I have. What about buying a brass bushing with 1-1/4 female threads and something small for the inside threads. I can chuck it in my lathe and use my boring bar to ream out the ID to make a nice slip fit to copper 1". Then sweat it.

 

[Reach4]

"What about buying a brass bushing with 1-1/4 female threads and something small for the inside threads."

The female threads of a bushing are on the inside, and male on the outside.

You want to make your own 1-1/4" x 1" Copper x Female Adapter?

OK... you want brass as an intermediary. Got it.

Here is brass:

1" Female Sweat x 1" MIP Full Slip Brass Male Adapter