The Stovebolt Site Forums The Shop Area Paint and Body Shop Compressor, moisture separator, and air hose reel

Would like advice from fellow Bolters on what piping material is the recommended for use in connecting these components. Went to Lowe's to purchase black iron or galvanized and they did not have all the fittings I needed. The employee in the plumbing section said metal pipe would be a problem even if I had a moisture separator and he suggested plastic pipe, such as PEX. Willing to read your suggestions. What works and what doesn't?

I'd go with PEX given the choices, No rust or corrosion issues and it's chemically resistant and no burst concerns that PVC has. There are several threads here is you do a search for PEX it narrows the field down...

I go by TP Tools & Equipment's recommendation for Air Line Hookup - Metal Piping Diagram.

I bought brass shut-offs from Harbor Freight.

My air-supply system has a cheap moisture separator. And, I have a refrigerator/cooling separator when it gets real humid (not very often) or when I am using the blast cabinet. I paint with a turbine HVLP system, so there is no need to worry about moisture when painting.

What size compressor are you running? May make a difference as to what size line i'd run. 10-15 cfm, should get by with 1/2" line, 15-30, I'd run 3/4.

Back to the "plumbing" guy at Lowes, I think you stumbled on someone who just knows you'll be back for some cutting and threading of black pipe (which they do free of charge). With PEX, he sends you out the door and doesn't have to get his hands dirty.


The benefit to PEX is that it's easier to install with typical tools. Copper you'll need to cut and solder. Black steel you may have to cut and thread. Unfortunate to the "plastics", they are quick to assume the temperature of the incoming air. So after a couple cycles of your compressor, the tubing is up to temperature and does little to "precool" the air prior to reaching your moisture trap. This lends the PEX as a better fit for an install that uses a cooler or dryer device to condense the moisture.

For the metal pipes, and likely something you'll see in the above TP tools link, most compressor/airline manufacturers such as TP tools recommends at least 25 to 50' of pipe prior to your water trap so that the metal pipe will cool/condense any water vapor out so the water trap can do it's job. If you've ever had water dripping out of your air tools even if using a water trap, it's because the water has not condensed and passes through the water trap as a vapor, and is condensing on the other side. If you live in a dryer climate, you may get by with closer to the 25' of metal pipe, more humid may require closer to the 50'. So IMO the metal pipe would be more suitable if you had no means of condensing the compressed air prior to a regulator/water trap. (cooler, refrigerant dryer)

And as an example of what NOT to use, here's an article on PVC pipe that exploded in a factory, sending many of the employees to the hospital with plastic shards imbedded....

http://www.wave3.com/story/17113807/explosion-at-fairdale-factory-injuries-reported

I guess there is a reason OSHA has the stuff outlawed for compressed air..

I did mine with 1/2" copper but if I was to do it again I think I would use the PEX

Good morning Tim,

This was a really good link. Gave me a lot more to think about and consider before I jump into something I might not be happy with.

Thank you,

John

Another vote for PEX. Mines held up for years.

And for moisture seperation a heater core plumbed in towards the end of the long run will do wonders on it own and for extra boost put it in a bucket of water.

i haven't plumbed my garage yet but my local flaps that deals mostly in paint also told me of the 25' thing for moisture. can a person just run a 25' coil of copper or does it have to be a straight line pipe. i am a believer of copper my self but a buddy of mine is using truck airbrake line and seems to be working great for him.

If you go with the airbrake line you'll need something like the heater core to help get the moisture out of the air. Since I added it to my line my moisture has dropped to next to nothing and thats without a water bath. I just happened to have a spare small 12"x12" out of a lincohn and gave it a shot for sh!ts and giggles. I cobbled some fittings and JB welded them in. I bet a radiator would REALLY dry it out Plus your have a built in drain valve!

If you are going to go with an aftercooler / moisture remover separator you want it as near to teh compressor as you can. The whole idea is to get as much water out of the air as possible before point of use.

I would not recommend using heater core or auto radiator on comprssed air over 15psi.

Dan Bentler

Well its working like a dream running 120psi 30 ft from the tank with a drop just after it before it re enters the garage... I had all sorts of water before I added it and barely a drop since. I guess not knowing any better works for some of us

every body ive talked to says a water seperator has to be a minimum 25' of line away from the compressor or else it's not going to work. i dont know why a guy cant just add a 12" sediment pipe down off of every air drop with a bleeder valve. kind of like in natural gas lines to our heaters we use in our shops.

A picture is worth a thousand hard to visualize (hard to understand) words.

The TP Tools & Equipment diagram at the link in my earlier post has well thought-out features to improve condensation and water-separation.

In addition to the use of metal piping:

Each "take-off" for an outlet from the main line uses:
- a riser,
- a T-fitting off the down-pipe (with "bleeder" at the bottom), and
- that"take-off" from the T in the down-pipe uses another riser before putting any moisture/oil-removing apparatus just before the terminal regulator/gauge.

This accomplishes the "sediment pipe" at each "air drop", described above.

So for full disclosure I am running PVC since when I was given the compressor I had a bunch of it laying around after using it as framework for an AgBag garage/shelter of sorts.
That said it or the preferred PEX makes retrofitting your system a lot easier than metal. Which is what I did with the heater core.
As I said it was a whim I had and as the core was just sitting there seemed like a way to test an idea. I figured if it worked to a degree I might upgrade if I needed.
heater core air line dryer
As a experiment I just grabbed what was laying around thus the braided water closet lines which just happened to be the right size for the core hook up lines. It does make it handy however as I can move it around and drain any moisture that collects in the core itself with the drop I just open the valve and blow it out. Prior to adding the core I had water in the line at the drop and also inside at the moisture filter which needed nearly daily blow outs. Since the core was added I have had nearly zero accumulation at the filter and open the clean out about once a week if that.
I'll no doubt upgrade when things begin to fail but/leak but it began as a test and so far the test continues>>>
Oh I forgot... I no longer use the bucket as it works without the water in it.

I think the manufacturer's have the 25' to 50' guideline when installed in ambient shop air situations. I have seen this installed in a manifold type of arrangement, up and down, repeatedly, to accomodate the 25 to 50 length in a shorter wall span. Realize here that each drop would need a drain.

Any time you can introduce a cooling mechanism, whether it is a coil of copper in a bucket of water, a heat exchanger/cooler, or a dryer system, you have now replaced the pipe length requirement with a device to perform the same function, likely more effectively. I have even heard of a copper coil passed through the shop refrigerator to cool the air and condense any vapor. (use caution with this not to drill through freon lines)

Other air system layout practices tend to fall under "common sense". Where the TP tools link shows some good theory, one of them still can be improved upon. One version shows a perimeter system in a loop, with all the "drops" that go up before dropping to the air outlet, using a separate drain. Where the other version shows more of a straight run, with any and all moisture dropping to the air outlets, requiring a moisture trap at each outlet. By simply using a 1" drop every 10' run in your system layout (to promote drainage to the end) and using the "all outlets go up before dropping", you will promote draining any moisture to the end of the line and not the outlets, as gravity works to keep it from the outlets. Following this scenario, you can use one drain at the end of the run instead at each outlet. Here's a link that shows my system for some examples of these..

http://www.garagejournal.com/forum/showpost.php?p=2100537&postcount=57

thanks for the info on the routing, what i really want to do is run the airline up into the attic and at every drop i want to install a 20-30 gallon air tank above them. this will add another 80-120 gallons into my air storage. thats why i am thinking about a 10 inch sediment trap with a drain on the bottom of each drop. also would like to either make a manifold or coil system before my drier/water seperator then out to my air plumbing.