Black pipe air line question

[mcarroll_nz]

Hey guys/gals, I've been a big fan of this site for a quite awhile and has been invaluable in helping me thru my 1,000sqft garage/workshop build decisions. Almost there and will post up pics when I'm done.

Last stage is putting in air lines for my 5hp compressor. I've decided to go with black pipe over copper as it should be a fairly easy win - no sweating of joints, just bolting the whole thing together like a giant lego kit.

Anyway, to initially cool the air I'm planning to run 30 ft of 3/4 inch black pipe down a wall with a slight decline and 1/2 inch water drops at each 10 ft join. Then loop back for another 20 ft of slight decline before going thru filter and water trap and then distributing off around the shop.

I'm guessing that black pipe is pretty inflexible, unlike copper, for bending in a slight decline after coming off another join. At the end of the 30 ft I was thinking maybe a hose to get the angles correct to looping back around.

I have another 20 ft to run across the ceiling to the other side of the shop so I have the problem all over again. Anyone got better ideas or suggestions for getting black pipe to give a slight decline?

Thanks.

 

[930dreamer]

With those lengths the pipe should have enough flex.

 

[Flail]

If you use black pipe I recommend “Tru-Blu Rectorseal” for the threads. Can get if from the Homey store.

 

[ChaseDE]

Yeah with that small of pipe it will flex (deflect) for your anticipated pitch just fine.

The only actual deflection would be the joint at the compressor. If you want to be real proper you come out the back with an ell pointed down slightly then go that way but the small pipe will naturally slope down if you let it without much stress.

When you loop back around with 2 ells, the second ell you should be able to thread and tighten to the desired pitch and if not add a union (probably a good idea anyway)

 

[Squankum]

You could get a lot more flex from PVC. I've heard if you put a really thick coat of black latex paint on it, that will make it stronger.

Can you assemble it all at ground level then raise it? Oh, wait, let me guess, the shop floor is not empty, is it?



_

 

[ChaseDE]

You are talking about probably 3 spools with 2 unions to really do it right and be properly serviceable.

I pup piece out of the compressor. A section for the 30' and a section for the 20' with unions between each piece.

Makeup the 3 spools then use the unions to get your drop right. See sketch. Orange circle is your compressor.

 

[Bretny]

Use 3/4 for everything. I have seen 1/2in pipe so rusted after only 15yrs that it had a 3/16 hole in the center. Or really do it once and use copper.

 

[mcarroll_nz]

Thanks for the responses - much appreciated.

I've been in two minds between copper and black pipe but thought I was set on black pipe. I'm thinking the pendulum's swung back to copper - easier to deal with on my own, being more malleable and a lot lighter.

I priced up the two today and was surprised the black pipe option will be more expensive, what with the gazillion fittings I need to buy - as opposed to buying 10 foot lengths of copper and spending a ton of time cutting and sweating pipe, not something I've done before. Six of one...

I'll post up a new generalized post with my intended air line design for the group to critique. Thanks again.

 

[marinusdees]

Thanks for the responses - much appreciated.

I've been in two minds between copper and black pipe but thought I was set on black pipe. I'm thinking the pendulum's swung back to copper - easier to deal with on my own, being more malleable and a lot lighter.

I priced up the two today and was surprised the black pipe option will be more expensive, what with the gazillion fittings I need to buy - as opposed to buying 10 foot lengths of copper and spending a ton of time cutting and sweating pipe, not something I've done before. Six of one...

I'll post up a new generalized post with my intended air line design for the group to critique. Thanks again.

My shop is 27+ years old. Air plumbed with black pipe. None of the awful issues forecast here on GJ. I won't live long enough to regret the blackpipe. I think I can deal with any issues now. I'm only 80.

 

[Lelandwelds]

My shop is 27+ years old. Air plumbed with black pipe. None of the awful issues forecast here on GJ. I won't live long enough to regret the blackpipe. I think I can deal with any issues now. I'm only 80.

Thirty inch steel pipeline wiggles like spaghetti if long enough piece.

Nothing wrong with black pipe once it is installed. Downside is all the cutting and threading. Use plenty of unions. Don't rigidly tie down until complete. Go to a for real supply house and buy your thread sealant there. Use 3/4 everywhere.

Copper works too. So does aluminum or pex.

 

[Boomer343]

http://www.silfos.com/htmdocs/product_support/alloy_selection_guide.html

This is a good link for soldering products and how to. I use Clean n brite 6 along with the Tec liquid flux. The solder isn't cheap but makes the job easy if used with the flux. Get it online or from a local refrigeration supply house.

This solder handles vibrations without an issue.

 

[ItsNemo]

I'm a black pipe fan if only because of how much more durable it is. You can get some flex out of it or just install a couple elbows and assemble with whatever slope you want. Unions are handy for repairs, pulling out sections, or just being able to get things together...I also used T's with a plug in one side instead of elbows in most locations so that I can split off a new line if need be without disassembling.

 

[Lelandwelds]

I'm a black pipe fan if only because of how much more durable it is. You can get some flex out of it or just install a couple elbows and assemble with whatever slope you want. Unions are handy for repairs, pulling out sections, or just being able to get things together...I also used T's with a plug in one side instead of elbows in most locations so that I can split off a new line if need be without disassembling.

It is a PITA to work with even with an electric threader. And, it is a special joy when it is all assembled and you check for leaks and find the malleable iron fitting leaks through solid iron. You get to take all that beautiful black pipe goodness apart and fling pieces across the parking lot. Ah, good times.

 

[isb cornbinder]

I installed black pipe for the air system in my 900 SF shop. That was in 1991.
The inside of the pipe started to give off some rust after a few years. I use parker air filters as required. The only problem has been intermittent particles holding valves open. A second blast and reconnect usually fixes the situation.
I am satisfied with my airline.

 

[kwb]

Had a nearly dead end apart out of my system that is 10+ yrs old and pipe was still nice inside. When I have tapped into the T's where a coupler would have done the trick in areas with more flow - no rust.

Not sure how so many have so much water to get pipes to rust like that.

All 3/4 Black Iron, No Dryer, No Cooling Loops, just a simple pipe out of compressor head and into the tank.

 

[Lelandwelds]

Had a nearly dead end apart out of my system that is 10+ yrs old and pipe was still nice inside. When I have tapped into the T's where a coupler would have done the trick in areas with more flow - no rust.

Not sure how so many have so much water to get pipes to rust like that.

All 3/4 Black Iron, No Dryer, No Cooling Loops, just a simple pipe out of compressor head and into the tank.

Isn't PNW famous for humidity so high it falls from the sky?

I have found if you understand "stuff runs downhill" black pipe works fine. Most of my installs were o2, c2h2, and n2 where water is measured in ppm. I have done side jobs for air compressors.

There is a big variance in black pipe quality. Does your compressor use oil?

 

[LandofRath]

I have iron pipe in my shop and never had any issues.. I have 3 drops and have never had water past the first one. and not much there. About to add onto the system..

 

[LandofRath]

Isn't PNW famous for humidity so high it falls from the sky?

We do gets lots of rain but not nearly as much humidity in the air as when I lived on the east coast.. With most of the wind running east or west and our mountains we tend to stay cooler and colder air does not hold as much moisture as warmer air so... That could be a big reason we dont see as much moisture as some have reported.

 

[ddawg16]

I used 3/4" copper. It was a lot easier to cut and sweat all the joints vs cutting and threading black pipe.

If I was going to do it again, I think I'd use PEX. Unlike PVC, if it blows, you don't send shrapnel everywhere.

 

[493mike]

I vote for PEX also. I do have copper in my shop but, PEX is CHEAP, pressure rated, available in straight lengths, and EASY to work with. Need a branch? Just cut and insert a tee! You do need to follow recommended air line design and routing for a good system.
Mike

 

[cadunkle]

Why use pipe for cooling? It adds complexity as well as joints to leak and does not cool very effectively. Run an aftercooler before the tank and catch your water there, it'll keep the vast majority of it out of your tank and lines. I used a large Hayden oil cooler, no fan on it yet but it'll drop temps around 200* and the water separator before the tank will dump huge amounts of water if running the compressor hard.

 

[Bretny]

Why use pipe for cooling? It adds complexity as well as joints to leak and does not cool very effectively. Run an aftercooler before the tank and catch your water there, it'll keep the vast majority of it out of your tank and lines. I used a large Hayden oil cooler, no fan on it yet but it'll drop temps around 200* and the water separator before the tank will dump huge amounts of water if running the compressor hard.

I did something like this years ago with a coil of 3/8x20ft copper and 1/2in copper prob totaling 20ft. Hangs behind my compressor. The heat that thing puts off is amazing. I get about a shot glass full of water out of my compressor tank every 3-6 months.

 

[mcarroll_nz]

I did something like this years ago with a coil of 3/8x20ft copper and 1/2in copper prob totaling 20ft. Hangs behind my compressor. The heat that thing puts off is amazing. I get about a shot glass full of water out of my compressor tank every 3-6 months.

I like the aftercooler idea and am considering a Hayden 1260. I want to start off with a basic install - oil cooler only with no fan or water filter. Will have a water drop and then uphill copper pipe back to the compressor.

Anyone run a similar configuration? In your experience is the filter necessary at this stage? Will be using a water and oil filter once it hits the main line so trying to cut back on the cost of a 2nd one.

Thanks.