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Topic Review (Newest First)
11-11-2004 08:44 PM
julmer I think our plant is plumbed with black iron also and it was built in 1973. We use enough air to warrant a 100HP screw compressor. The system was originally set up with a big drier up in the mechanical room. The major difference is that most industrial applications can tolerate fairly low quality air or have the necessary filtering built in to the machines that need it. When building a system where painting will be a regular activity, I'd prefer to be a bit more fussy right off the bat.
I'll probably nitrogen purge and silver solder mine when I do it but I have the stuff on hand because I do a little A/C work.
11-11-2004 07:37 AM
pmeisel Echo on the drip stubs -- and the filter -- and another thing, make sure you drain all the water out of the tank either once a week or every time you use it if less often... and plumb the pipe so you can drain water and blow down the piping once every few months -- and your system will last you for years.

Factories than run all kinds of things on compressed air use black iron pipe and it lasts for years. Now we use air dryers but we used to just rely on the filters and a semi-annual blow down.
11-10-2004 10:03 PM
julmer Yes, pipe threading oil! I've never owned a bottle of the stuff so I use whatever is handy, usually the nearest quart of motor oil.
The only thing I'd say about black iron is be sure and put drip stubs (they should be there regardless of what kind of pipe) below your outlets and filter it right at the wall when you paint.
About copper and pressure. Copper is used extensively for residential water systems where working pressures can range up to 150 psi. That is with generic soldering techniques. There are a couple of different grades of copper and the better stuff is used in air conditioning where it may see 400 psi. The only real difference is the A/C stuff is usually braised or silver soldered. I'm going to be doing my garage soon and I plan on using copper. The only thing unusual is I'm going to use long radius elbows designed for A/C work.
One thing I've seen done is some shops is to run a large (6" or bigger) pipe down the center of the shop and branch off of it for other lines. If it's very long, it eliminates the need for a separate storage tank.
11-10-2004 08:14 PM
Iron Pipe

I've been in the garage tonight looking at the iron pipe I purchased. It is coated in orange primer on the outside as standard nowadays due to many plumbers complaining they have to spray it themselves. Upon closer inspection I noticed the inside of the pipe to be painted grey. This grey paint could prevent it from rusting internally. So all is not lost.

I suppose having spent a small fortune on this pipe, I might as well use it. If it does give me trouble later on then I'll strip it out and install copper. In hindsight copper would have been better because its easier to work with. I also wouldn't of had to spend more money on a pipe threading kit. Oh well you live and learn.

Anyone know what kind of oil is used to lubricate when threading a pipe manually? Don't say pipe threading oil I wonder if I can get away with a little engine oil?
11-10-2004 07:02 PM
Iron pipe

WEll in over 40 years in the trades always used the black iron for air only lasts about 30 years or so in service so should be ok..Never had any complaint about rust flakes or any of that..

UPC (the plumbing code specified iron pipe) so that is what we used..Only time I have ever experienced any issues was when the filter/seperator was not serviced on a regular basis..
11-10-2004 02:30 AM
Copper pipe

Thanks for the info Julmer. Unfortunately I've just spent a small fortune on Black iron piping and fittings.....if only you mailed a few days ago

I did wonder to myself if copper piping was up for the job. I thought that soldered joints wouldn't be strong enough to contain compressed air and would eventually leak. I would of rather used copper piping because it cheap and very easy to work with.

I'm now in a dilemma, do I assemble the black iron piping or do I accept a loss and use the 3/4" copper piping I already have in my garage? Hmmmm.
11-10-2004 12:53 AM
julmer Black iron pipe is a poor choice for air lines. Its black because it has no coating. It is used for natural gas because gas has a detoriating effect on the zinc used to galvanize pipe which causes the zinc to come loose and end up in the gas stream. Little gas orifices don't like that at all.
The problem with black is that it rusts. Moisture in you air lines will rust the inside of the pipe and then you will be dealing with rust flakes entrained in your airstream. Compressed air and galvanized pipe seem to get along just fine. My personal chioce is copper pipe. It's light, can be assembled with nothing more than a propane torch, is very smooth inside, and helps cool the air off better.
I've had a couple of people say that the total installed cost is only a bit more expensice than other methods and you have a lifetime job.
11-08-2004 04:18 AM
Black iron Pipe

Just a little note to folks in the UK who are having trouble finding 'Black iron pipe'. It seems not very popular and hard to locate.

I found a company called PIPELINE based in north London that stock black iron pipe and fittings. Address & phone no. are as follows:

Mowlem Trading Estate
Leeside Road
N17 0QJ

(0208) 808 6633

Click here to view a map and get directions.
11-03-2004 10:38 AM
electriclightfoot The instruction manual does say to run with the lines wide open for a specified period to run her in.

Can't thank you enough.

11-03-2004 10:26 AM

the schedule 40 pipe is what we use for gas piping..Dunno what it s called in the UK but I am reasonably sure that you guys use natural gas for heating your use that type of pipe..Same stuff..

Blowing down the air ines is done by opening the drain valve of your filter wide open and letting the air escape..and opening the drain on the compressor wide open..the air rushing out takes the excess moisture out...let it run until the air is dry then shut off the compressor..

Really simple deal to do..drains off any accumulated water in the lines and tank.. there ya go.

One more thing when you put in the new compressor let it run witht the lines wide open for a break in period...shoudl say something about that in the manual...
11-03-2004 09:17 AM
Compress setup

Brilliant! One more thing, I've never heard/come across "black iron pipe schedule 40" over here in the UK. Is there another name for this piping?

Also you talked about at the end of the day/session, turning off the compressor and "blowing down your lines". How do you do this? Do you literally blow with you mouth? I know it's a daft question but I'm slowly getting there

thanks Dean
11-03-2004 08:51 AM

Yup your diagram is fine,,,put the filter air /water seperator regulator at your work station..

There you got it
11-03-2004 06:58 AM
Setup plans

Thanks very much guys for your input.

I designed a quick diagram - see attached file. Tell me if its ok or where I need to change things etc. and whether there should be a moisture filter/coalescer filter?!? somewhere in the setup?


11-03-2004 03:10 AM
julmer There have been a couple of different threads on the subject on this forum. Search a little and you should come up with lots of ideas. The only big caution I would add is DO NOT USE PVC (plastic water pipe) for your project.
It looks quick and easy but the pipe will fracture on impact and send shards of sharp plastic all over your shop - and you if you are in there.
11-02-2004 11:20 PM
Chopper64 Try this link. Lot of good info here.

This was posted a few months back. There is a link to an oldsmobile website that has some diagrams on piping.

Good luck, as I am in the same process of plumbing air lines in my garage also.
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