Quality air line pipe unions?

I plumbed my shops air supply with 3/4 copper. Love it, easy to install and and cools the air pretty quick over the 40+ feet or so that it runs.

I installed motorguard brand filters/regulator combos as well as desiccant dryers and motorguard M60 filters for all the cnc machines and plasma drops.

Issue is, the motorguard filter/regulators are junk, and I'm swapping everything over to NORGREN brand separate filters and regulators. Because I mounted all the filters to studs and then hard-ran the copper to said locations, there is no easy way to remove the motorguard equipment without damage to the copper piping.

I'm having to cut into the copper to remove and replace the old filters and regulators. Is there any good copper unions that I can use to make future maintenance and replacement of filtering equipment easier? Or should I just hard-run the copper to the new equipment (as before) and plan on repairing the copper again if I ever need to replace equipment in the future?

Most of the box store pipe unions have crap reviews. Is there a brand you guys/gals recommend? Or, is it just more cost effective to hard-run everything again?

This supplier seems to have good reviews for their copper sweat unions: 33582 - Elkhart 33582 - 3/4" Copper Union

No personal experience with them.

You could use a flare fitting. They seal well and are easy to take on and off. The tube and the regulator stay stationary and you turn the nut with a wrench. Much easier than NPT fittings.

McMaster-Carr

I'm partial to the old school compression/brass ferule fittings Swagelock.

Not the (sharkbite) stuff

Would you consider using Shark Bite connectors? IIRC the pressure rating is 250 PSI.

My experience with unions is that their mating surfaces are not usually perfectly mating, but can be made to fit by lightly lapping the mating halves against one another, being careful to rock the halves during lapping to ensure good cone-to-ball contact over a range of angular misalignments.

One of the runs has a mist lubricator for air powered tools, so for that run at least I would want to stay with copper. 'm not sure I would trust PEX tubing (shark bite) just yet, reminds me too much of PVC. There is an aluminum product out now that uses shark bite fittings. but I want to limit the mixing of metals if I can.

Couldn't I just use high flow air fittings to connect the filters to the main supply trunks? I've never seen this done, but it looks/sounds like a good method? The end use devices are all 3/8 air lines so as long as I keep all the supply runs larger or the same size as that, I shouldn't have any flow issues, right?

Mud said:

Would you consider using Shark Bite connectors? IIRC the pressure rating is 250 PSI.

Click to expand...

Or mebbe 300 PSIG?

Around ten years or more of use now, I have learned to love 'em for waterlines - COPPER NOT PEX (they are able to do either..) - as much for their ability to swivel and be opened back up easily as to not have to deal with a torch trying to sweat a fitting in tight spaces.

Hong Kong, nearly everything is compression. That wants use of costlier imported Australian, not Chinese, Copper tubing, having a "rounding" tool to-hand, and a light touch with the pipe cutter, even so.

Flare has much the same needs - EG: the goods are cheap enough per-joint, but want more expert attention to detail to get "right", hence a time-PITA vs Shark-Bites-on-Copper.

2CW

If you have soldered connections in the system it is a mistake.

This is the way to go. Compression fittings for NPT to tube and tube to tube. Ham-Let or Hoke brands.

A 7/8" tube to 3/4" NPT fitting.



Ham-Let Group - Straights

My suggestion would be brass sweat unions, not copper. I've never had any luck with copper unions, but brass seems to never be an issue.

Tonytn36 said:

My suggestion would be brass sweat unions, not copper. I've never had any luck with copper unions, but brass seems to never be an issue.

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Or use threaded brass or better yet bronze unions in to the FRL etc etc with copper to thread fittings on those, .that way servicing is easy, as is replacement of worn unions etc etc etc.

In my book if done properly (as in old school and the way I was taught) serviceable items like FRLs, steam traps, pumps etc etc etc, should have isolating valves fitted either side, so the unit can be shut off and serviced with the minimum of air / fluid loss and time.

Limy Sami said:

Or use threaded brass or better yet bronze unions in to the FRL etc etc with copper to thread fittings on those, .that way servicing is easy, as is replacement of worn unions etc etc etc.

In my book if done properly (as in old school and the way I was taught) serviceable items like FRLs, steam traps, pumps etc etc etc, should have isolating valves fitted either side, so the unit can be shut off and serviced with the minimum of air / fluid loss and time.

Click to expand...

Isolation and independent shut-offs are nice but.. EVERY component added is one more to buy, one more to install, one more that may go wrong or need periodic maintenance.

KISS. It is often a great deal cheaper to skip the extra parts and just shut-down the whole system - or a major branch - the few times actually NEEDED to replace the fewer, simpler, parts that MUST be there.

As to unions.. lest we forget, the Shark-Bite 'clan' can be taken apart easily with the aid of a Cee-shaped clip to push in the sleeve that latches the seal. If one is damaged or leaking, new one can go directly into its place. No more tools are required for a swap than a few of those clips, colour-coded for tubing size, no heat, solder, dope or thread-tape, and not a lot of time, either.

Monarchist said:

Isolation and independent shut-offs are nice but.. EVERY component added is one more to buy, one more to install, one more that may go wrong or need periodic maintenance.

KISS. It is often a great deal cheaper to skip the extra parts and just shut-down the whole system - or a major branch - the few times actually NEEDED to replace the fewer, simpler, parts that MUST be there.
.

Click to expand...

True, BOTOH, in the case of compressed air(and we don't know the OPs circumstances ??) a small shop may well be okay without air for say 1/2 or a full hour, but a bigger shop or plant may well be a different story and speed be of the essence.

Plus a simple shut off valve needs very little maintenance.

Horses for courses.

Limy Sami said:

True, BOTOH, in the case of compressed air(and we don't know the OPs circumstances ??) a small shop may well be okay without air for say 1/2 or a full hour, but a bigger shop or plant may well be a different story and speed be of the essence.

Plus a simple shut off valve needs very little maintenance.

Horses for courses.

Click to expand...

My puny Campbell-Hausfield wheel-around's first mod before ever firing-up was a tee with a ball valve - Shark-Bite, of course - to a QD fitting in each leg of the crossbar, so... "I hear yah" .. even at the lowest-end of the scale.

Still and all, a Shark-Bite is sooo fast to swap, no need to overdo it.

Downside? My average cost per fitting is between USD $5 and $10 per-each higher than sweat, compression, or flare. Worth it to me in reduced kit-out hassle. Not to mention far easier alteration AND better re-use / re-purpose of the fittings , if/as/when need be.