Heres this. --------------------------------------------------------------------------------
I wrote this up a couple of days ago on another forum, anyway.
With galvanized pipe you have galvinization inside the pipe, that could plug up a regulator or filters.
Also black pipe will rust inside, but I think the rust is the lesser of the two evils.
Whichever you use might be a wash, but my experience with black pipe has been really good.
So lets get down to the basics here, the heat from the compressor heats the air going into the pipe, as it cools it turns to water, so, we know have either rusty water or pieces of galvinized flakes going with it.
Our main concern here is trying to get long life out of our air pressure regulator, and most important is to keep rust or flakes or water out of our paint gun or air tool, or keeping the moisture out of our sandblaster pot.
Water will take the rust and flakes with it, and this is one of the things that will eventually do an air tool in.
So, we plumb our air lines on a taper so we don't have any flat spots, (where water can lay in the pipe).
At the bottom of these lines we put in drains to get rid of the rusty water or flakes.
In order to cool the hot air you put in a minimum of 50' of pipe, 75 to 100' would be better, then your pretty sure of your air coming out at more of a room temperature if possible, I probably shouldn't use room temperature.
At the end of this long run of pipe, thats where you put your filters. You will still have some water and rust or flakes or whatever coming into this first filter.
I use an f-88 sharpe filter, but no doubt there might be some out there a lot better then the f-88s, but these work good.
At the end of my long pipe run, I have three f-88s one after the other right in line.
These f-88s have a white stone type filter in them.
A couple of years ago my compressor bit the big one, so I changed it out.
So I took out the stone filter in all three of them, the first filter was pretty brown looking, the second one was a little tinge of brown coloring to it, and the third one was almost snow white, and mind you they have been in three quite a long time, I never have to change them out, only did because the compressor let go.
Now if i would have had galvanized pipe, would the flakes have gotten through to it, I don't have a clue on that, maybe or maybe not.
Heres another thing, I have been buying air tools since 1980, anyway I bought a bunch of them that year, thats 28 years ago, some of these air tools are just average priced air tools, not expensive but not the cheapest either, anyway, the only air tool i have ever replaced was a metal crimper and a couple of good napa air ratchets, worked them to death, they were good ratchets.
I counted my air tools the other day, because I haven't been working in the garage, I would give each one about three drops of air tool oil every 3 or 4 moths, and run them a few seconds, this is a good thing to do if you don't use them on a regular basis.
Anyway a couple of times I oiled them I forgot about one in my regular tool box, so I count them now, theres 23 of them and they all work just fine.
Did these 3 f-88s filters and a good set of tapered air lines keep these tools this good for that long, maybe, I'm not out there every day, but they have gotten a lot of use over the years.
Would galvanized or copper or whatever air lines have been better, maybe.
I'm 66 years old and can still work pretty good, so i still use these tools today. As you get older you don't get any smarter, maybe you get dumber, probably, buy older guys have seen more s**t happen, so you learn over the years if something works really good, its best to leave it alone, in most circumstances anyway.
I've set here and beat the drum on the black iron pipe and how i like it, but if something works good, you know the deal.
Hooking up a good set of air lines takes some planning and a little researching, the extra time looking at different setups will save you time and I would bet a good amount of money, in air tool life and wasted paint.
I'm not real sure on copper lines and how they cool compared to black pipe, maybe there better and probably rust free, but there are other things with copper that need to be looked at, but the galvanized or black pipe will take a little more punishment then the copper.
Running long lines of pipe and keeping it from leaking is a job. If you take a small wire brush and clean all your pipe connections with that and some lacquer thinner, you will have a lot less chance of a leak.
I use pipe dope or tape, it doesn't matter, I probably have about 150 or 175' feet of pipe run in all different directions, with zero leaks, but it took me a while to get it that way.
Its going to take you a while to run it, but once its in you can forget about it, and if you run it right you don't need an air dryer, I run a couple of sand blasters and a fairly large bead blaster, and I don't have a moisture problem with silica sand, and thats the worst stuff you can run if you have any moisture in your lines.
The air line drawing I put up a couple of post before this, gives a decent overview on how to run your lines without flat spots, hopefully somebody can get some good out of it.
You will see some mention of automatic drains on filters, for a commercial body shop thats probably a good deal, but as a hobbist, you might want to get the ones with the little wingnut, drain it at the end of the day, and check your finger tips, if it feels slippery something let loose in your compressor, and this could save you some major airline redoing to get the oil out, don't ask me how I know this.
I was pretty long winded on this, sorry about that, but if just one of you read it and get anything out of it, I guess it was worth it.
I will say this though, galvanized or copper might be better, but this black pipe works good for me.
Heres that drawing again, its about four feet long, thats the reason for the sections.
http://www.1969supersport.com/draw1.html
Rob
http//www.1969supersport.com