copper or black iron pipe

[gmhill33]

Which is better or preferred? Black iron seems to be about half the price.

Thanks,
Gary

 

[nehog]

Sewer, water, gas, air, oil, electrical?

 

[gmhill33]

I guess it would help if I mentioned that is for air.

Thanks,
Gary

 

[930dreamer]

I used black pipe. Copper is easier to cut and solder.

 

[gmhill33]

I used black pipe. Copper is easier to cut and solder.

Is there a way to hold the black iron pipe off of the wall? I know they make a couple of different things for copper.

Thanks,
Gary

 

[porcupine73]

I used black pipe for my system. If I ever have this job to do again I will probably go copper. Maybe its because I used pipe and fittings from the hardware store and cut and threaded a few of my own pieces, but I had quiet a few leaks in my system after commissioning. Some were a real pain to fix and some I haven't found yet. Plus putting all that pipe together was a lot of work. It just seems copper would be much faster, easier to work with, and less chance of having leak problems all over the place. The main reason I went with black pipe is I read something about in a fire, copper connections can come apart, and then blow compressed air into the flames.

To space my black pipe off the wall, I basically just used short pieces of 2x3, then lag bolted the pipe U clamps through the piece of 2x3 and into the garage wall, ceiling, etc., wherever I was running it. It's not as pretty as it could be but it works.

 

[fflintstone]

I am blaming the poor quality fittings these days but despite having sweated pipes for well over 30 years, I find I have an initial failure rate of over 10% when I sweat ¾ copper these days.

 

[Goobzilla]

Did black iron in my 32x34 in WA and again in my new 40x64 in CO. Chopsaw and hand threader, only 2 leaks when done that were easily fixed. The price is right and really not as much work as some would lead you to believe. Good luck whichever way you go!

 

[SM Racing]

Just did copper. With as much moisture as we have in the South, Copper was the only thought. Black iron would rust way too fast. Had one leak when I was finished. Actually forgot to solder a joint at all, but otherwise it was great.

 

[sdowney717]

rusting pipes. there is a lot of water that gets in the compressed air.
So perhaps your using your iron system and those abrasive iron rust particles get into your air tools or maybe your paint if you spray..

 

[Falcon67]

Black iron here. Add plenty of unions in case you need to add drops or service a line. Wrap the chinese fittings with about 6-8 turns of good teflon tape and a little bit of good pipe dope and you'll have minimal leaks IMHO.

 

[GN4WHLN]

Copper. Just go to get it done. I've got my compressor boxed and sound deadened and I think I am going to add one of the HF dessicant driers.

 

[brats.n.harleys]

PVC. Haha. Just kidding. Copper cools better and looks nicer to me.

 

[JohnJL]

I'm a complete plumbing novice and did copper with no leaks on the first shot. See my thread last week.

 

[rickycobra]

If black iron can hold the compressed air then go with that.

 

[djd99]

I've had black pipe for for 20 years and not 1 issue. Painted over 50 cars and still going strong.

 

[GeorgiaHybrid]

I ran with copper. For me it was quicker to run, looks nicer and it will never have a rust issue.

 

[rockchucker]

I would personally use Copper. If you ever need another drop you just cut the pipe, add a tee and Solder it up. Black Pipe is a whole other process. 3/4 Copper and run with it.

Just my .o2

 

[gmhill33]

Just did copper. With as much moisture as we have in the South, Copper was the only thought. Black iron would rust way too fast. Had one leak when I was finished. Actually forgot to solder a joint at all, but otherwise it was great.

Dumb question I'm sure but is there any special copper or can I use the stuff that they sell at Home Depot or Lowes?


Thanks,
Gary

 

[GeorgiaHybrid]

Dumb question I'm sure but is there any special copper or can I use the stuff that they sell at Home Depot or Lowes?


Thanks,
Gary

Use type "L" copper that the big box stores sell and you will be OK. It is a medium wall pipe and is fine to use for airlines. Type "M" is thinner and is "iffy" on compressed airlines. The pipe will have the type printed on it down the length of the pipe.

 

[MichaelP]

You can get everything from Home Depot. Buy Type "L" pipe and use 95-5 solder. Both of them are rated for this kind of pressure.

I may also suggest tinning flux since it's easy to work with.

 

[rwhite692]

I did mine all in 3/4" black iron pipe prior to insulation/sheetrock and it's inside the walls and the space above the scissor trusses.

If I were to do it over, I probably would do it w/copper. Although in my case, working up inside of the scissor trusses with a torch would have been challenging.

With the black iron pipe I also had a bunch of small leaks to go around and fix, took me a while to get them all. Rectorseal #5 was great, I had several joints that just wouldn't seal with teflon tape no matter what and using the Rectorseal did the trick.

 

[Aberdale]

I used 1" black pipe for the main runs, and 3/4" for the drops. I've had no leaks with the black iron, but have a few small leaks with the cheap quick disconnect fittings. I'll upgrade them someday.

I made stand-offs for the black pipe out of 6" lengths of 2x4. I drilled a hole in the middle the size of the pipe OD. I then cut the 2x4 in half through the hole. Reassemble with deck screws, sandwiching the pipe in the middle. It was quicker than it sounds. I made up around 36 of these "brackets" in about 40 minutes.

Dale

 

[akdiesel]

I will be the odd ball here.
I know it was not in your choices but I went with 3/4" stainless tubing.
I work with this stuff all the time so I am cofortable with the bends and the connections. I also get a good rate from our local dealer in town. I did three walls of a 40' x 60' shop with 6 drops. I can not remember the cost but I wanna say it was acturally cheaper than using the Rapid Air stuff. I think I paid about $60 for a 20' stick of 3/4" .035 wall.
It will outlast any of use, easier to add to than copper or pipe, and higher pressure ratings (even if it is only air). I even used 1/2" lines for my pressure washer which is on the other side of the shop and used the wall brackets to hold them together for a nice fit.

 

[fflintstone]

With the black iron pipe I also had a bunch of small leaks to go around and fix, took me a while to get them all. Rectorseal #5 was great, I had several joints that just wouldn't seal with teflon tape no matter what and using the Rectorseal did the trick.

what is the story on this rectorseal 5? I never use teflon tape, but allways use paste. how does it compare?

 

[RMR&C]

Dumb question, but why not use galvinised (sp) steel pipe? No rust issues then.....

 

[kornbln]

for standing off the wall, unistrut would work nicely.

 

[c39er]

Dumb question, but why not use galvinised (sp) steel pipe? No rust issues then.....

Thats what I used-heavy wall galvanized pipe. Has worked great for 15 years. No flaking or rust.

 

[fireguy]

Ward fittings beat chinaman cheap, crappy pipe fittings. If available, I always purchase American made pipe fittings.

 

[waltmcq]

I just liked the way copper looks

 

[Bruce4310TX]

black pipe rusts and harder to work with, Copper cools better clean and easy to work with but costs more.

 

[jdaallen]

Use type "L" copper that the big box stores sell and you will be OK. It is a medium wall pipe and is fine to use for airlines. Type "M" is thinner and is "iffy" on compressed airlines. The pipe will have the type printed on it down the length of the pipe.

3/4" Type M copper tube is rated at 400 psi internal working pressure. It will work just fine for the home garage air system. I've used it for years in comercial garages and never had a problem. With any grade copper system, the anchor system is important at the stress points.

 

[Skin]

copper is more expensive, conducts heat better and cools faster, looks better, requires more care during setup and of course soldering. Black iron is cheap and can be done with just some teflon tape or paste. For me the former would be a weekend project, the latter would be an afternoon.

 

[MrMark]

Black iron here. Add plenty of unions in case you need to add drops or service a line. Wrap the chinese fittings with about 6-8 turns of good teflon tape and a little bit of good pipe dope and you'll have minimal leaks IMHO.

Sad, but true. Black pipe is hard to work with these days. The fittings are poor and the pipe is too. Even getting it to hold 15 pounds for natural gas test is a challenge. You have to crank the s#$%t out of it and it will still leak. You do need the dope (rectorseal with teflon is good, megaloc is bad, very bad) and tape (yes, we mean both together, although 6 wraps is pushing it - how about 4?) if you are going that route. I'm a purist and don't consider that method kosher so I wouldn't use the stuff.

Look for three threads in the fitting and three threads out of the fitting, anything other than that or pretty close and you have some problems. NPT is made to meet at about three, or three and a half, threads. Remember its a taper thread that crushes together and relies, allegedly on metal to metal contact, except it is a poor system and needs help from the dope and tape. Another tip on black pipe: don't ever back up a fitting if you have to line up a fitting or whatever. You must go all the way around again. Plan for this issue and it's tough to do.

Black pipe is a pain in the *** to do right, no question. Without a threader, forget it.

 

[MrMark]

black pipe rusts and harder to work with, Copper cools better clean and easy to work with but costs more.

And there you have it! Nothing more need be said.

 

[saabman]

I have used black iron pipe for 25 years. No leaks at 175 psi. I find that short pieces of pipe sold at the box houses are thin, while 10 and 12 foot sections are thick wall. A pipe cutter and threader are necessary tools when working with pipe. Main lines run in 3/4 and drops in 1/2 inch. Use a braided flex coupler at your compressor.

 

[kc-steve]

I agree Saabman. I think the techniques used in building the black pipe system are critical to having a low or no-leak system. I used two wraps of pipe tape and made sure to align pieces without backing off any to align. My system leaks at a rate of about 3 to 5 psi per hour which I don't consider to be bad at all for my needs. The small leaks probably come from the unions I installed so I can replace pipe, if necessary, in the future.

When I don't use the pipe system I close it off and take compressed air directly out of the compressor. Most of the time my system is shut down with no compressed air though.

And definitely buy the high-pressure flex pipe out of the compressor to avoid noise being transmitted to the rest of the house, in my case.

But my primary concern was cost, so it was black steel pipe for me. Maybe one day when I have a lot money to throw around I might use copper.

Steve

 

[z28toz06]

Thats what I used-heavy wall galvanized pipe. Has worked great for 15 years. No flaking or rust.

I'm not sure, but I think the "galvanized" is only on the outside, like black pipe is only black on the outside.

As far as unions go on black pipe, you can buy true unions for copper also. You just sweat them on.

 

[akdiesel]

I agree Saabman. I think the techniques used in building the black pipe system are critical to having a low or no-leak system. I used two wraps of pipe tape and made sure to align pieces without backing off any to align. My system leaks at a rate of about 3 to 5 psi per hour which I don't consider to be bad at all for my needs. The small leaks probably come from the unions I installed so I can replace pipe, if necessary, in the future.

When I don't use the pipe system I close it off and take compressed air directly out of the compressor. Most of the time my system is shut down with no compressed air though.

And definitely buy the high-pressure flex pipe out of the compressor to avoid noise being transmitted to the rest of the house, in my case.

But my primary concern was cost, so it was black steel pipe for me. Maybe one day when I have a lot money to throw around I might use copper.

Steve

3-5 psi an hour loss seems to be out of the norm for most systems. Especially if it is a simple home air system.
Every time you need air you have to wait for it to pressure up and alot of unneeded wear on your motor. I have also seen some systems start to leak from a system that is pressurized and depressureized constistantly which tends to work the connections.
You could try and put a little pipe dope on your union connections to help it seal better.

 

[sneezer41]

I've done both. copper was easier, I put a drop every 10 feet[at the end of each pipe] prefabed the drops on the bench. One leak on a ball valve. Iron drove me nuts, never stopped leaking, pilot error I know, but still....