Railroadman

New air compressor is set up and wired in. Next step is to run some lines and related accessories such as air drier. I have a Harbor Freight blast cabinet I will be running from it, about 6 feet away. And will want at least to lines to the shop, or rather one line with at least 2 outlets.

How may air driers - one before the cabinet, and one for the shop line? Or one at the far end of each shop location?

Any particular type? Any other advice? I'm figuring on iron pipe, not something stupid like PVC. What other factors should I be considering?

Thanks!

Pic is before wiring - it now sits farther back in the alcove, on rubber strips cut from an old tire. Direct wired, 240v, 10 gauge wire put in by a licensed electrician.

dafloi001

I use black pipe with a filter dryer and regulator near the compressor and just run it out to your drops. I did in stall a smaller regulator and dryer on my blast cabinet just to be convenient. Never had any moisture problems. I also have a auto drain on the tank. I R makes a nice electric tank drain. You could also use copper tubing

Roger Walling

Run 3/4" black iron pipe and angle it down so that it may drain.

Most sites say to angle it toward the tank but I think that it should go in the direction of the air. Use downpipes and have a valve on the bottom to drain. Take the air off the same pipe with a tee, at least 6" above the drain.

Use as large of an air dryer as you can afford. Place it as far away from the tank as possible and before the first outlet.
You will still have water in your blast cabinet if you use it for a long time as they use such a large supply of air.

A fan blowing on to the tank and the air cooler will help cool the air, allowing the moisture to drop out in the tank.

63 340HP

On the air side, the first line of water transport defense is a automatic tank drain. There are many electronic valves, but the traditional idiot proof method is to install a small steam trap like an Armstrong 1-LD (1-LD Liquid Drainer). The link has a file download for a pdf document on how to pipe it with the compressor. Source it from a commercial plumbing supply house or parts house like Granger. The advantage of a steam trap is the larger drain valve that resists blockage, and a reliable passive float that is designed for a 50 year life with harsh steam (it will outlast you).

The primary air dryer and water/oil filters need to be near the compressor before the first distribution manifold or branch to any equipment, and before any regulator to step down pressure. The goal is to remove water & oil, and prevent water and oil migration, before it gets to your shop piping. You do need a good primary filter like the Hankinson NGF series. The link has a file download for a pdf document explaining filtration and oil separation. The lowest grade SF filter will catch everything larger than 3 microns (good enough for shop use except for high quality painting). You can always spend more, for better removal of solids and oil (like the HF series).

Secondary air dryers usually are unnecessary with a good primary air dryer. Why filter already filtered air?

A commercial refrigerated air dryer, like a Hankinson HPR 5-10, is overkill unless you plan to use the shop air for SEMA exhibit quality painting (and helps if you do).

If you plan to run air tools with an auto-oiling system, run a second network of dedicated tool piping separate from the shop air piping. Mark or color code each valve, to identify tool air with oil, separate from clean shop air.

You may not like PVC, but it does not rust. Schedule 80 PVC that is properly installed with extra hangers to minimize sag, and bracing at the valves where the flex line for a tool hook up is installed, will survive a long long time. If you are sour on PVC, install copper, because it does not rust (avoid steel pipe unless it's stainless because of rust).

Railroadman

Wow, some good info there - thanks! I have some sketching and some shopping to do!

Muttley

For a smaller shop, you may want to consider a kit from RapidAir. The piping is designed for compressed air, won't corrode, looks good, and you don't need much in the way of pipe fitting skills to put it together. It's available through Amazon and a number of other retailers:

https://www.rapidairproducts.com/

On PVC, this one always generates opinions. You will undoubtedly be able to find piping rated for the pressure, but the problem with PVC is its failure mode. Unlike a liquid, compressed air stores a lot of energy, and PVC tends to fail via brittle fracture. That means if it does let go, the compressed air will propel sharp pieces of plastic in random directions, with great force. I don't believe it's worth the risk, no matter the odds of that actually happening.

wolfman64

/www.rapidairproducts.com

Railroadman

Uh-oh! Now you've gone and done it! That looks like something I may not be able to resist!

At first glance that looks nice, does anybody have negatives about something like that?

63 340HP

The Rapidair system kits make it easy, and the tool hookup ports that mount rigid to a wall or backing pole are very nice. HDPE pipe is what is used in most new underground natural gas piping installations, and the Rapidair aluminum case just adds to the durability. The kits simplify the design process. The need for more pipe clamps in a surface mount system is the same as with any flexible pipe system.

PVC pipe failure shredding is a concern with little observed data to back up the premise. PVC has almost no mass, and a shard carries almost zero momentum when it breaks. That said, some State's ban the use of PVC in compressed air applications (but allow more brittle ABS plastic pipe that is even more dangerous). The greater PVC problem is heat. I have seen 3/4" PVC pipe soften under the heat of a 500W halogen lamp clamped to the pipe, and balloon into a football size section until holes formed and air leaks stopped the deformation. Copper is always the reliable pipe of choice.

skids

http://cached.tptools.com/Images/air...ng-diagram.pdf

outofspec

Nice compressor Don! Save yourself some aggravation, and get good quality quick connects, for your drops and tools. There’s various good ones out there. I chose Milton, because they are readily available and reasonably priced. I got mine at JBtoolsales.com . Also, there are a few different design platforms, I.e, automotive, industrial. I don’t think it matters what one you use, but you need to be consistent. I was constantly disappointed with the air leaks in my Chineseum connectors and finally bit the bullet, and got all new matching Milton’s.

Paster

Moved to a new place last year. When I was planning my air lines I contacted Motorguard and asked for their recommendations. I was advised to have a minimum of 20 feet of hard line before the moisture filter to allow the air to condense so that the filter could do it's job. I mentioned that I had a limited amount of space in the garage closet and it was suggested that I use a coil to provide the 20 feet.

The red flexible line on the left comes from the compressor and allows for a quick disconnect if I need to move the compressor out of the closet. (house water heater is in the same closet and will need to be replaced someday)

One thing I should have installed is a drain on the downpipe from the coil. I will add that someday.

I used to get moisture in the blast cabinet when I had the compressor set up in my old house without the 20' hard line before the moisture filter. Now I get none.

I did consider using one of the RapidAir kits but once I got started with the copper decided to use it for the entire install.

-Michael

Railroadman

Nice setup, Paster, and it looks so much like air compressor line the revenooers will never suspect you're making moonshine!

By 20 feet of "hard line" do you mean without take-offs or outlets, or are you talking copper or iron as opposed to flexible plastic? Would 20 feet of the Rapidair work, or it needs metal for heat transfer?

The only thing I don't like about your layout is all that sweat soldering. I have done it, I can do it but not well, and I don't like doing it. Maybe by the time I got done with all that, I'd be better at doing it.

benrep

I used copper and compression fittings. Easy to use and can be changed out for modifying the system. No soldering! Copper is easy to bend to your will, around corners etc. It is also easier to cut with a tubing cutter.

John McGraw

I absolutely disagree with the notion that either a refrigerated or desiccant dryer is overkill. In any compressed air system, the air inside the pipe will be completely saturated. That is to say, that the air inside the line will be at 100% relative humidity at all times. All the good advice about nice long runs and metal pipe to help condense water out of the air line, is very good advice, but the fact remains that the air is still going to be at 100% relative humidity, unless you introduce a process that drops more moisture out. You might ask why this is important, so here we go.

Assume that the temp of you shop is 80 degrees, and therefore the air lines and the air inside them are all 80 degrees, and the air is at 100% Relative humidity. As soon as that air passes through an air tool, a blast cabinet nozzle, or the nozzle of a spray gun, that temperature will drop dramatically, and moisture will condense to whatever moisture level equates to 100% humidity at that temp. This will leave little drops of moisture in your blast stream, or in the paint you are shooting. It is not at all uncommon for the temp at these points to drop to 40 degrees F, or even lower. When I use air tools for an extended period of time, I have to wear gloves, because the tool gets so cold!

Keep in mind, that relative humidity, is exactly that, RELATIVE. It is a measure of how much moisture air can hold at a given temperature. As the temp goes up, air can hold way more moisture, and as the temp goes down, it can hold way less. When the temp goes down, the moisture has to fall out of the air stream, until it reaches the saturation point (100%).

What a refrigerated air dryer does, is to drop the temp to just above freezing, to drop out the excess moisture, and then when the air warms back up to 80 degrees, the temp drops to less than 2% relative humidity!

This makes it almost impossible to condense moisture out inside an air tool or nozzle.

I have both a refrigerated air dryer and a desiccant dryer in my shop. The Hankinson refrigerated dryer drops the dew point to about +40 degrees F in most of the shop, and then I use the desiccant dryer for the painting regulator, and it drops the dew point to -40 degrees C on that line. Air used for painting can never be too clean, or too dry. Most commercial paint shops use this same level of dryness, and for good reason.
The desiccant dryer is kind of a pain to regenerate, as I have to bake the desiccant in the oven until it turns blue again, to drive the moisture out. Fortunately, this dryer is large enough, and with the already dry air from the refrigerated dryer feeding it, I only have to regenerate about twice a year. The refrigerated dryer is very low maintenance, as it automatically drains out the water as it accumulates. I pull the moisture trap off once a year to clean it, but otherwise it is zero maintenance. If you keep an eye on Ebay and Craigslist, you can find a clean, used 10-15 CFM unit for a few hundred dollars, and it is money well spent.


Regards, John McGraw

Paster

Great info John, Thanks! I'll have to keep an eye out on Craigslist for a refrigerated dryer.

The way it was explained to me by Motorguard was that they recommended metal lines for the first 20' leading up to the filter. Iron pipe was not recommended because of the rust potential. Also no 90 degree bends before the filter so I used 2 45's to make a 90 degree bend. The copper sweating wasn't bad at all, it's the first time I had done that and when the job was done only one junction was leaking. Easy fix, just reheated and applied a bit more solder. I just made sure each junction was completely clean and used liberal amounts of flux on each joint.

John McGraw

All my lines are copper as well. but I do this stuff for a living, so it was kind of a no-brainer for me. A lot of guys use iron pipe, and it is fine. You are, after all, going to be filtering the air before you use it.



Regards, John McGraw

John McGraw

Another little tip on the refrigerated dryer, These dryers are designed to just run non-stop 24/7/365, but I did not want mine to run when I was not in the shop. they do not consume much energy, but no sense in wasting electricity! I have a pressure switch that turns it on when I open the ball valve as I walk in the shop. My compressor is in another shop, and I have gotten in the habit of shutting the valve as I walk out the door every night.

Regards, John McGraw

Roger Walling

One problem when using plastic pipe or soldered copper that has not been mentioned is what happens when fire hits the pipe.
The flames melt the plastic or solder turning the piping into a massive, turbo charged blow torch, spreading the fire all over the shop.
I have black iron in my shop for over 40 years and except for an occasional cleaning out the drain valves because of small rust particles, I have never had a problem. Besides that, black iron is easy to modify the system for additional outlets.

Robert61

PVC pipe failure shredding is a concern with little observed data to back up the premise. PVC has almost no mass, and a shard carries almost zero momentum when it breaks.[/QUOTE]



30 years ago a friend plumbed his automotive shop with pcv. I said I don't think this is a good idea. One day one of his down spouts blew off flew across the shop and hit a customers tire. Fortunately a tire and not the body or somebody. Recently I was working on the compressor where I'm doing the body work on my 61. I was changing the pressure switch. I knew he had pcv inside but I didn't know he had it outside at the compressor. I'm nor sure if I touched it or what but the fitting broke popped me once and flailed around a few seconds while the pressure bled down from the inside hose. It may be easy maybe neat and won't rust but DONT DO IT. Jmo