Air Lines....black pipe....

[alex2929]

I have a bunch of 3/4 black pipe and fittings. I want to run some air lines in my shop so I think I'm going to use it. Most of it was used for airline for about 1 year....a few pieces are new.....but its in good shape.

My compressor is on the other side of my shop that isn't fixed up. I am thinking of have a port right by the compressor. Then i would go up to the ceiling and get it in the shop. Once I get a line in the shop, I would basically have a "T" shape with one drop/port on 3 different walls.

A couple questions...
------------------------------------
Best way to seal joints? Tape.....dope.....both?

The ceiling wont be as conveniant to install but i think will make my walls look less cluttered in the end. Any issues with this?

Any reason i can't paint the pipe once its up? a few pieces have a little more surface rust than others.....I think this would look nice and not be super hard.

Mounts/Hangers....I was thinking of using a split ring hanger with a mount and 3/8 threaded rod. This would get me away from ribs on the metal and on top of electrical conduit and stuff. Any other ideas?

Would it work to put a union or two in the lines or am i asking for leaks? I was thinking if I had issues at some point down the road these may be really nice.

My "switch" for my compressor will probably just be the breaker which is right by the entry door. I was thinking of trying to find some sort of electric ball valve that is normally closed i guess? can't imagine it would take much of anything to open it, so maybe i could wire it to one leg of the 220. The ball valve would open when the breaker is on and close when the power is off???

 

[imagineer]

I did an air loop (actually, it's more of a "U", 18' x 24' x 30') using 1/2 black pipe. I used yellow pipe sealant at all joints. In hind site, I should have used tape and better quality sealant, but after tightening a few connectors, it doesn't have any leaks. Also, in hind site, I should have used 3/4" pipe (for added air volume and I think it would have threaded better).

My system has only one union, right before the main water filter and regulator. I have 5 air drops and a hose reel at the end of the 18' run.
Each air drop has an extra 12" of pipe beyond the "T". At the bottom of which is a ball valve for draining any water.

As far as mounting the pipe, I just used EMT conduit clips and screwed it to the underside of the roof trusses or to the header joists.

 

[karoc]

Few years ago I read someplace that it’s better to run pipe to where it makes complete loop. I believe so that there’s no drop in cfm’s, true or not I don’t know. But I would put drip legs in at raise where go up to ceiling and st each drop. Help keep condensation to minimum

 

[alex2929]

Few years ago I read someplace that it’s better to run pipe to where it makes complete loop. I believe so that there’s no drop in cfm’s, true or not I don’t know. But I would put drip legs in at raise where go up to ceiling and st each drop. Help keep condensation to minimum

I figured on drops with ball valves at the end. I could see the loop idea make sense. I don't think i'll use it enough that it will really matter.

 

[bdbecker]

Loops are great in an industrial application because of all the people potentially using air at the same time. However, unless you've got some really high CFM tools, 3/4" pipe for a single person shop should be more than adequate without a loop.

Compressed Air - Size of Pipe vs. Capacity

Air pipe lines capacities at pressure <i>100 psi (6.9 bar)</i>.

www.engineeringtoolbox.com

 

[rattle_snake]

Black pipe has + & - 's like the rest. It absorbs heat and will cause the moisture in the air to condense out in the piping. So you want a filter/reg at every drop, if the application needs a filter or a regulator. Put a drip leg in the first vertical run out of compressor up to ceiling.

Use both paste and tape, paste first.
Unit strut is a good hanger method, with the associated pipe clamps.
No unions. If it leaks, then add.
No need for elect ball valve.

 

[dave*99]

My "switch" for my compressor will probably just be the breaker which is right by the entry door.

Most breakers are not meant to switch loads on and off routinely. Post a photo of the nameplate on your compressor motor. The HP rating, voltage and current will dictate the wire size, breaker size and wiring method (direct or plug and receptacle)

 

[Stuart in MN]

I know you're using black pipe, but the Rapidair website has a useful diagram showing a typical layout - the principle is the same no matter what kind of airline is used. https://www.rapidairproducts.com/wp-content/uploads/2019/05/LOOP-DIAGRAM-9-2015.pdf They also have a design tool feature on their website where you can draw up a system, again the principle is the same.

Teflon tape will work fine as long as it's used properly. Don't wrap the joint a million times, and make sure there are no strands hanging inside the airline. Dope works too, it's really a matter of what you're comfortable with.

The more joints or couplings you have, the more chances there are for leaks. Use couplings where they're needed, but I wouldn't put in any just to have them.

The pipe can be painted after installation, it won't affect how it works. Black iron pipe is usually kind of dirty and oily, so make sure you clean and sand everything so the paint will stick.

A simple toggle switch can be wired in series with the compressor's pressure switch if you want to disable operation when you're not present.

 

[trashauler]

I just did 3/4 black pipe in mine over the weekend. I debated even doing it as I hardly use the compressor anymore with battery tools. I ended up doing two walls. The bottom 8 foot of my walls is osb and the top side is metal siding. I ran it at the top of the osb and used unistrut to mount it. Went up fast.

 

[OccupantRJ]

Here is the thread on my black pipe air line install if you want to take a look.

RJ's Progressive Air Piping Thread

I have been working on the air compressor piping for my shop for a while now, installing as I got the time and inclination. The system is feeding two media blasting cabinets, providing general shop air through 7 drops, and providing two external through the wall outlets for outside use, one on...

www.garagejournal.com

 

[NUTTSGT]

If you're going to paint it, I would paint it first, then touch it up after you're done.

I would do tape and dope. I didn't and do have a slow leak somewhere. Not enough to worry me but yeah, both.

Mine is mounted near the top of the wall and drops come down. Each drop has a "tee", quick connect, valve w/drop leg drain.

I used hydraulic hose between the hard line and compressor and air reels.

 

[no704]

Have a drip leg or have your fittings come off the top of the pipe to prevent water in your drops. Mount the horizontal runs with a little slope with a drain on the low end.

 

[T444e]

I prefer Loctite 545 on compressed air piping. I supported mine with strut and strut clamps. Use unions only as necessary. I second NUTTSGT, paint first then touch up.

 

[Kaizen]

I did this in my old garage and would not recommend it. The vibrations eventually caused leakes at pipe dope seams. I made a heat sink on the wall going back and forth at an angle that drained past the compressor and to a drip leg. It worked well for that. But man oh man when i took that system apart it was rusted tight all through it. And not just a surface but actual crusty's of rust. I trashed it all after that and went with the blue plastic stuff and glad i did. Even if i had a ton of it for free with fittings i'm not sure i'd want to do that again.

 

[TurnipTruck]

I used new 1” galvanized pipe with US-made fittings placed on top of the truss bottom chords (in the attic, under a foot or two of insulation) from the compressor at the front of the shop to a half dozen drops at the rear. I used hydraulic hose to prevent stress caused by movement at the compressor and the two-post.
Until I added a second and third air hose reel, the system would hold pressure for several months.
It is pretty dry here, so I haven’t noticed or experienced rust flakes in the six years in this shop or the thirty years at work. (The humidity stays low because it’s in solid form for 200 days of the year.)
All pipes chamfered and reamed, five wraps of blue monster tape and a wipe of generic pipe dope, tightened as much as I could with 18” pipe wrenches and a bum shoulder (therefore not oilfield tight!).
All told, all that 1” galvy plus the 1-1/4” black gas line was $400 delivered. The fittings were largely dumpster finds, but I had to buy the more unusual fittings.

 

[rattle_snake]

If you have air hose reels, they will leak somewhat. It is what it is. So a minor leak in piping probably won't be noticed.

My compressor had been constantly powered for 25 years. Only one time did it have a run-away condition, when the head gasket went out. The motor went into thermal and protected itself and the pump. I only shut off power when I go on vacation. The system is always pressurized.

The soft hose on the lift pictured above is helpful as the posts do move at the top.

 

[djjsr]

Clean threads, tape first for 2 or 3 wraps, then a little dope over the tape. I'm not a plumber but I had an old guy tell me that and I've never had a leak.

 

[jimkinney]

The only one I helped install in N. Alabama rusted and plugged up several air tools.
Definitely need dehumidifiers and filters.

 

[finn]

If you're going to paint it, I would paint it first, then touch it up after you're done.

I would do tape and dope. I didn't and do have a slow leak somewhere. Not enough to worry me but yeah, both.

Mine is mounted near the top of the wall and drops come down. Each drop has a "tee", quick connect, valve w/drop leg drain.

I used hydraulic hose between the hard line and compressor and air reels.

My shop is plumbed in 3/4” black pipe. It has a leak somewhere up high, near the ceiling, where it goes over the door.

I’m not climbing a ladder that high to fix it, so I live with it. I did install a ball valve at the compressor tank outlet, and the leak is slow, so it doesn’t materially affect capability, but if I forget to shut the valve, there’s not much pressure left in the morning.

I do the majority of my work in a 24x32 room that was added later, and that’s fed by an air hose now. This spring I’ ll order a MaxAir or knockoff to that room. The black pipe isn’t worth the hassle of dealing with it when there are quicker, and probably cheaper and easier methods of running air now.

 

[thammel]

All the concerns about rust flakes had me do my copper system. Very happy with it!

 

[gba2331]

All the concerns about rust flakes had me do my copper system. Very happy with it!

I also polished and sprayed a clearcoat so the copper stays pretty!

 

[CraigStu]

Mine is a 120V compressor so I put a twist the knob timer on it. The timer controls both the compressor and a 120V air valve on the compressor outlet. I crank it to 60 minutes, it opens the valve to charge the piping to the 2 hose reels, and as I use air the compressor cycles. Best thing is I never have to remember to turn it off. I am not sure if the same is available in 240V but you could use a timer to control a 240V contactor to power the compressor.

 

[teknikfrog]

Black pipe has + & - 's like the rest. It absorbs heat and will cause the moisture in the air to condense out in the piping. So you want a filter/reg at every drop, if the application needs a filter or a regulator. Put a drip leg in the first vertical run out of compressor up to ceiling.

Use both paste and tape, paste first.
Unit strut is a good hanger method, with the associated pipe clamps.
No unions. If it leaks, then add.
No need for elect ball valve.

You can install compressors outdoors?

 

[alex2929]

Thanks for all the help.....I think i have some ideas to go with.

Wish i didn't have the black pipe laying here.....i would just buy a rapid air pipe system.

 

[Highbeam]

Thanks for all the help.....I think i have some ideas to go with.

Wish i didn't have the black pipe laying here.....i would just buy a rapid air pipe system.

No law against scrapping that old iron pipe.

 

[larry4406]

Thanks for all the help.....I think i have some ideas to go with.

Wish i didn't have the black pipe laying here.....i would just buy a rapid air pipe system.

My last shop I ran black pipe. Didn't stay there long enough to know if it rusted. My supply line was down low, sloped downhill in the direction of flow, with the taps off the top and a drain on the far end. I did not want a drip leg at every tap. My piping was inside the walls.

My current attached garage, I ran copper in the walls as I harvested it from when we gutted the basement. However, I want to relocate my compressor to the detached barn, so I need to get from the garage, into the basement, outside to connect to the direct burial Rapid Air product already in place, and then in the barn run the piping.

I too have a large stash of black pipe and threader for this project. I am 62 and thinking that the black pipe lengths will work for me and my time left.

 

[GrayFlattop]

My last shop I ran black pipe. Didn't stay there long enough to know if it rusted. My supply line was down low, sloped downhill in the direction of flow, with the taps off the top and a drain on the far end. I did not want a drip leg at every tap. My piping was inside the walls.

My current attached garage, I ran copper in the walls as I harvested it from when we gutted the basement. However, I want to relocate my compressor to the detached barn, so I need to get from the garage, into the basement, outside to connect to the direct burial Rapid Air product already in place, and then in the barn run the piping.

I too have a large stash of black pipe and threader for this project. I am 62 and thinking that the black pipe lengths will work for me and my time left.

I installed 3/4” black pipe when I built my garage around 1990. Mounted on unistrut with 1/2” black iron drops. The drops each have a tee pointing up from the main runs. I have a 6” drip leg on each drop. At the time I used a ptfe pipe dope. No issues with the piping in that time. Typically the only leaks in that time have been the regulators or the quick couplers.

If I had it to do over, I would have used type L copper - but only at 1990 prices. Current copper pricing would be far too much $.

 

[scooby074]

Im all black pipe in my home shop. Everything is pitched down to drip legs to catch any rust or water. I filter before the black pipe to try and drop out any water I can. Anywhere you have a T to have a drop for a hose, make sure the T is facing up, this will keep dirt from making it too your tool.

 

[SouthernIllinois]

I used 1/2” and 3/4” black pipe for a red neck cooler moisture separator. After that it goes to 1” Transair aluminum pipe with a filter/regulator at each drop.



The jumper hose from the black pipe to the blue Transair pipe isn’t connected in this pic.

 

[HoosierBuddy]

I'm a little shocked by how many people are on the "use tape and dope" bandwagon.

I'm unaware of any pipe sealant maker or teflon tape maker that would instruct you to do it that way.

So, my recommendation would be to use one or the other. To nail that down a bit, based on my experience it's easier to get leak free joints with a quality pipe sealant than it is with teflon tape. To be even more specific, I recommend Rectorseal #5 pipe sealant. Their instructions include stirring thoroughly, clean the threads, apply to male threads only up to 1 1/4". Apply to male and female if larger. I allow it to tack a bit (maybe 1 minute) but that isn't in the instructions. Assemble joint to ansi standards (hand tighten and then tighten another 2-3 turns). For pressures above 100 PSI allow to fully cure before pressurizing.

Oh...also if you haven't got your elbows, tees, and couplings yet....I'd recommend getting them at a plumbing supply store rather than a box store. Maybe they are better now, but I've seen some pretty jank fittings from my box store in the past.


So...personally...I did this in 2006 on my shop air system. It's still working great. I have not gotten the rust issue. That said....I do have an automatic tank drain on my compressor and another manual drain that I use regularly.

 

[nadogail]

Compressed Air pipe systems should take into consideration many different factors including the size of both the compressor and the load on the system. Another important factor is the budget and materials on hand.
If for example you have a large stock of iron pipe and fittings, it would make a lot of sense to use what you have, instead of buying a lot of Copper Pipe and Silver Solder to make a system for a small compressor In a home workshop. Rubber Hoses are inexpensive and easily modified as needs and priorities change.
Anybody can be a Monday Morning Quarterback when they are rambling on about how they would spend someone else’s time and money.

 

[T444e]

I only use tape and dope when the pipe threads are in poor condition, i.e. 50-100 year old piping and replacement requiring opening wall/floor. New install dope only, compressed air Loctite 545. I know fitters that use dope on tape on every joint, belt and suspenders.

My compressed air system is type L copper.

 

[SouthernIllinois]

FWIW, RapidAir requires tape and dope for their compressed air plumbing.

I ended up going with Transair for my compressed air plumbing and it doesn’t require either for their fittings.

 

[Metal-Marc]

Black pipe has + & - 's like the rest. It absorbs heat and will cause the moisture in the air to condense out in the piping. So you want a filter/reg at every drop, if the application needs a filter or a regulator. Put a drip leg in the first vertical run out of compressor up to ceiling.

Use both paste and tape, paste first.
Unit strut is a good hanger method, with the associated pipe clamps.
No unions. If it leaks, then add.
No need for elect ball valve.

This bugs me.

There I fixed it.

 

[SouthernIllinois]

FWIW, anyone considering using RapidAir or Transair aluminum piping - look at what is available locally.

Foolishly, I started buying RapidAir fittings and tools without looking at the shipping costs.

For me the cost of shipping the 20’ sections of pipe was more than the cost of the pipe itself. If I recall correctly, the shipping alone was around $500.

Come to find out a local family owned auto equip dealer sold the Transair system and would deliver all the parts for free.

I have had the RapidAir parts listed on here for half price for months with no takers.

The blue piping in these pics is my Transair plumbing.



I did use black pipe off the compressor to the first filter and then it ties into the plumbing.

I have Motor Guard filter regulators at each drop. This is for air tools and primer only. I am lucky in that my best friend has a bodyshop less than a mile away with a brand new down draft booth with a 220v refrigerated air dryer system.



These are the RapidAir parts I’m trying to get rid of. If anyone is interested, I’ll make you a hell of a deal.

 

[larry4406]

FWIW, anyone considering using RapidAir or Transair aluminum piping - look at what is available locally.

Foolishly, I started buying RapidAir fittings and tools without looking at the shipping costs.

For me the cost of shipping the 20’ sections of pipe was more than the cost of the pipe itself. If I recall correctly, the shipping alone was around $500.

Come to find out a local family owned auto equip dealer sold the Transair system and would deliver all the parts for free.

I have had the RapidAir parts listed on here for half price for months with no takers.

The blue piping in these pics is my Transair plumbing.



I did use black pipe off the compressor to the first filter and then it ties into the plumbing.

I have Motor Guard filter regulators at each drop. This is for air tools and primer only. I am lucky in that my best friend has a bodyshop less than a mile away with a brand new down draft booth with a 220v refrigerated air dryer system.



These are the RapidAir parts I’m trying to get rid of. If anyone is interested, I’ll make you a hell of a deal.

Nice Corvair!

 

[jhelrey]

I'm all copper. Easy to run and easy to make changes.

 

[Firebrick43]

FWIW, RapidAir requires tape and dope for their compressed air plumbing.

?What? For the npt side of the npt adapters just like your transair npt adapters do. The pipe side of the fittings are compression fittings in both the maxair and fastpipe lines and require no dope or tape

 

[SouthernIllinois]

?What? For the npt side of the npt adapters just like your transair npt adapters do. The pipe side of the fittings are compression fittings in both the maxair and fastpipe lines and require no dope or tape

You’re right.
I misspoke.

What I should have said is RapidAir on their installation instructions is to use BOTH tape and dope on the npt side. That was the point I was trying to make - poorly at that.

I shouldn’t have spoke about RapidAir fittings as I have never used them. I have a box of unions and T’s I can’t give away.

 

[Milton Shaw]

I have a bunch of 3/4 black pipe and fittings. I want to run some air lines in my shop so I think I'm going to use it. Most of it was used for airline for about 1 year....a few pieces are new.....but its in good shape.

My compressor is on the other side of my shop that isn't fixed up. I am thinking of have a port right by the compressor. Then i would go up to the ceiling and get it in the shop. Once I get a line in the shop, I would basically have a "T" shape with one drop/port on 3 different walls.

A couple questions...
------------------------------------
Best way to seal joints? Tape.....dope.....both?

The ceiling wont be as conveniant to install but i think will make my walls look less cluttered in the end. Any issues with this?

Any reason i can't paint the pipe once its up? a few pieces have a little more surface rust than others.....I think this would look nice and not be super hard.

Mounts/Hangers....I was thinking of using a split ring hanger with a mount and 3/8 threaded rod. This would get me away from ribs on the metal and on top of electrical conduit and stuff. Any other ideas?

Would it work to put a union or two in the lines or am i asking for leaks? I was thinking if I had issues at some point down the road these may be really nice.

My "switch" for my compressor will probably just be the breaker which is right by the entry door. I was thinking of trying to find some sort of electric ball valve that is normally closed i guess? can't imagine it would take much of anything to open it, so maybe i could wire it to one leg of the 220. The ball valve would open when the breaker is on and close when the power is off???

I ran my ball valve to the 120 volt light circuit. When I switch the lights on the air turns on. Works great isolates the air compressor without having to cycle the circuit breaker and keeps the air secured from leaking down. I used a heavy duly hydraulic hose to connect to the valve and air system.