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Darren

Ultra Member
Premium Member
I was supposed to have a custom system built for my shop in 3/4 half halo, with 1/2" drops all in black pipe. Customer was going to pipe it all. Tired of waiting and tripping over hoses on the floor. I've done systems in PVC, no failures, but not doing that here. Considering pex based system, copper ($$$ ouch), or a rapidair type system .

I'm ruling out iron if i have to deal with threading. It will never get done. No time.

Shop is 36x50, so the half halo 3/4" mainline would be around 110', with a total of 8 drops. The drops can be 1/2". Likely the whole system could be 1/2" but if i ever get an apprentice, i want to make sure we don't have pressure drops. The 1/2" drops would be 10' long (14' ceiling).

Looking at rapidair type systems online, I haven't found a customizable system, just packages. Makes me lean towards a pex based system. If i need to add to it in the future, running to HD is more attractive than chasing down a proprietary fitting.

Any thoughts? Experiences?
 

DavidR8

Scrap maker
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I have 100' of pex and fittings in the shop all ready to run. Looked at Rapid Air but it was horrendously expensive.
 

Darren

Ultra Member
Premium Member
I'm definitely leaning towards pex. the best part about the rapid air systems is the blocks. But i can make them, or make them up with off the shelf fittings.
 

Jswain

Joe
I always hated black pipe because over time it scales/rusts bad inside the pipe. You need some heavy filtering & replacing the filters to make up for the additional work with heavy use.

I like copper & used that for my air system because it's basically lifetime, easy to add to anywhere, and cools down the air so if you have enough copper ahead of your filters they more easily remove the moisture. If you're not painting/sandblasting this might not be of concern to you though.

PEX is a good choice because it cheap, if you are painting or sandblasting you will need(or want) additional filtering or a cooler likely to get the temp down enough to remove the moisture.
 

Susquatch

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I'm definitely leaning towards pex. the best part about the rapid air systems is the blocks. But i can make them, or make them up with off the shelf fittings.

I've learned to hate PEX water lines SOOOO MUCH, you would have to connect me to 24kv through each testicle to get me to try running air that way.

My whole house is pex water. It is constantly leaking someplace. I just finished installing a fancy new laundry tub for my wife. The water connections were those new pex push-to-connect fittings. God awful design that sprayed water everywhere. Had to resort to new shutoffs with crimp on connectors. Didn't matter what I did, they failed the go-no-go test. I finally just tightened the collar and resigned myself to the possibility of another future leak.

Copper or galvanized might cost more, but that's what I'd be doing if I were you. My own choice would be copper.
 

jcdammeyer

John
Premium Member
I did my shop with this:
Although originally listed at $199 for the kit it appears the list price is now $169 and on sale for $119. Way cheaper than copper.
 

Susquatch

Ultra Member
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I did my shop with this:
Although originally listed at $199 for the kit it appears the list price is now $169 and on sale for $119. Way cheaper than copper.

The only problem I see is that I think @Darren needs high volume for his shop.
 

JustaDB

Ultra Member
Did mine in 3/4" black pipe (main & drops) ~28 years ago, w/ a double wire hydraulic hose connecting to the compressor (I was concerned about vibration). Perimeter run w/ a drop on each wall (4). I still use the one nearest the compressor the most (airing up tires, blowgun & air tools for projects, tire changes on the driveway, etc). I also have a 1/2" self-retracting hose reel connected at that point.

The balance of the perimeter is valved separately from that position. I occasionally use the drop directly over the workbench & have used the one closest to the back yard once. I have brass radiator-style drains at the bottom of each drop. They were the only mistake I made on that project. PITA to open/close. I will be replacing them w/ 1/4" brass ball valves at some point. I think that will help clear out any interior corrosion, too.

Reason for the 3/4" black pipe? It was free. Costs were the fittings & threader rental. Oh, & beer for Dad & I...
 

DavidR8

Scrap maker
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I've learned to hate PEX water lines SOOOO MUCH, you would have to connect me to 24kv through each testicle to get me to try running air that way.

My whole house is pex water. It is constantly leaking someplace. I just finished installing a fancy new laundry tub for my wife. The water connections were those new pex push-to-connect fittings. God awful design that sprayed water everywhere. Had to resort to new shutoffs with crimp on connectors. Didn't matter what I did, they failed the go-no-go test. I finally just tightened the collar and resigned myself to the possibility of another future leak.

Copper or galvanized might cost more, but that's what I'd be doing if I were you. My own choice would be copper.
Odd. I’ve run literally hundreds of feet of pex working with my plumber nephew in law. Never had a leak.
 

Darren

Ultra Member
Premium Member
@Jswain I started looking at copper but its pretty expensive right now. I've ran a fair bit of copper and sweating the fittings isn't a big deal. easier than threading pipe.

@Susquatch if i go with Pex, it will be the crimp rings or the expander type. There won't be any sharkbite fittings.

@jcdammeyer that system is pretty much the same as used in trucks with the push to connect fittings. I have mixed feelings about using it in my application.

@JustaDB I will have 1/4 turn drains at each drop.
 

Darren

Ultra Member
Premium Member
The only problem I see is that I think @Darren needs high volume for his shop.

I should probably do some calcs and research. Compressor is 25ish cfm, 175psi. Biggest demands are die grinder, 4.5" air grinder and blast cabinet. I can probably get away with 1/2" at 175psi and regulators at the drops . Right now i have 2 regs at the compressor, one at 100, one at 150.

Trying to avoid some design mistakes like we had at at the last shop i worked at. If 2 air impacts were used on the same branch, you could feel it.
 

Dan Dubeau

Ultra Member
I like copper. Black iron rusts, and I still don't trust plastic, even though I know PEX is rated for pressure and much different than PVC (which is a huge no). I don't currently have a compressor worth running lines for, but when I do it'll be 3/4 copper main and 1/2 drops with drip legs. I picked up a very cheap container full of 3/4, and 1/2" elbows and tees a few years ago, so I'll only be out for pipe and a couple threaded fittings and valves.
 

mbond

Well-Known Member
Premium Member
I my experience, there is a knack to making a PEX crimp. The first dozen or so I attempted had chronic leaks. But then I got better at it and haven't had a problem since. It is so much faster and cheaper that it is hard to go any other way
 

phaxtris

(Ryan)
Premium Member
Premium Member
My whole system is copper like some others here

I don't know if I would do copper for the op's size of system, that would get hella expensive, pex would be fast, easy and inexpensive

I've never had an issues with pex or shark bites and leaks, at least with water, I have never used it for an air system
 

slow-poke

Ultra Member
I just replaced the copper in the garage with PEX. The copper was just routed in a weird way with a low spot that would collect moisture and moisture and Ottawa winters are a bad combination. Touch wood the PEX is working great so far.

One thing I overlooked when using copper is how restrictive all those 90 degree bends are when you add them all up.
 

Mcgyver

Ultra Member
I've not had trouble with a Pex crimp connection, maybe just a bit of luck. I does seem risky compared with a proper soldered joint. otoh i've had the odd pin hole leak develop in copper pipe so its not bullet proof either.

One thing with PEX is it doesn't like UV light. There is some 30-60 day max period it should exposed to direct sunlight. Not usually an issue when its run through walls, but might be in shop if surface mounted and there are lots of windows. Makes it brittle and may crack, but its not suppose to shatter/explode like PVC
 
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