Suggestions for running shop air lines?

[Downeaster]

I'm thinking 3/4 PEX and a RapidAir kit for about $200 that has 100' of line and enough components for 3 drops.

Questions:

1. Do I really need 3/4 or will 1/2 do? 1/2 is cheaper but I wonder if it will move enough air for a small blast cabinet and occasional use of air impacts and ratchets.

2. Kit, individual components or a combination? I'd like to add a ball valve at the compressor and make provisions for a drain leg at the compressor as the first run will be about 6 feet vertically to get out of the compressor room.

3. Is there an affordable (sub $100) air drier that actually works?

4. Where should the air dryer go in the system - Right at the compressor or just before the drops?

5. Regular PEX or the PEX-AL-PEX stuff?

 

[RustiePyles]

DE it really all depends on what you plan on doing with your air system? 1/2 is fine for most things, if you plan on doing a lot of painting and using an HVLP gun or doing a lot of sandblasting I'd go with 3/4. What I would do is come off of my compressor with a 3/4 line with 1 port then reduce it down to 1/2 for the rest of the run.

 

[alfredo]

For the pressure to ID of hose check out this chart (link to site with more details). This PDF from a separate site is also a pretty good source of info.

As for the dryer - I would suggest plumbing in a $50 or $100 desiccant dryer directly after a medium to large standard water filter. The desiccant lasts forever, just cook the moisture/oil/vapor off in an oven when the granules fill up. I doodled up something real quick to better visualize what I mean:

That should get you as far as you're looking to go without having to implement a full evap. Hope that helps.

 

[RC4MAN]

What I learned in industry is go bigger, especially if you're running tools that need lots of volume. Air motors, air grinders, air impacts all need either lots of volume or lots of air NOW for a short time.
On job sites we ran 1" hose everywhere with 10' long 1/2" whips at the tool for smaller tools, 3/4" whips for the "Harley Grinders", big 10" disc air grinders.
I worked in a shop once that ran PVC for air line, 90 psi max., it worked but would let loose on occasion. I like the sound of PEX if you think it's up to it.
Personally I'm a fan of rigid metal pipe and threaded fittings.

 

[kshansen]

For the pressure to ID of hose check out this chart (link to site with more details). This PDF from a separate site is also a pretty good source of info.

View attachment 196592

As for the dryer - I would suggest plumbing in a $50 or $100 desiccant dryer directly after a medium to large standard water filter. The desiccant lasts forever, just cook the moisture/oil/vapor off in an oven when the granules fill up. I doodled up something real quick to better visualize what I mean:

View attachment 196593

That should get you as far as you're looking to go without having to implement a full evap. Hope that helps.

When the shop I worked in for 45 years was set up with air we plumbed it up with 1 1/2 galvanized pipe. Now you have to understand that the shop had most of the time half a dozen to one dozen guys working there and some could be running 3/4 inch air wrenches at the same time so volume was a big factor. Back then about the only "air dryer" was a small tank on the outlet of the main tank with a float valve that opened when water level got high.

One thing that was done is on all the drops as shown in Alfredo's drawing is there was a Tee and about a foot of pipe below it with a drain valve that could be open to drain any water. The connector for the air hose was in the side of the tee. My sketch is not as good as Alfredo's but you might get the idea:

 

[GLJ]

If you brass for your shop I just bought these of of Amazon. They look like very good quality. 6 ball couplers. Plus they came in a nice case.
https://www.amazon.com/AmazonBasics...5HDJ54AZ9B5&psc=1&refRID=3ESYQ3TJHF5NTKZQZA9R

 

[Jim]

Another thing to take into account is the number of tools expected to run at the same time. The ID of a standard QD coupling is 1/4" So conceivably a 1/2" line would work just fine for anything using that coupling.... as the 1/4" restriction would be the choke point. Granted, ID wall drag for long runs means you'd need larger than 1/2" line, but not by much considering the size of your shop.
Using two identical power tools at the same time would double CFM carrying ability needed.
But keep in mind the the 1/4" "choke point as the limiting factor unless you plan to go with larger QD coupling.

 

[Downeaster]

@kshansen - That's what I did with the black iron pipe plumbing for the original installation in my garage. That works fine, but EVERY threaded joint leaks. Partly because I used teflon tape instead of pipe dope (or both...) like I should have and partly because it's crappy Chineseum pipe with even crappier threads.

I intend to leave the existing plumbing in the garage and go with new in the shop. It sure looks to me like the PEX-AL-PEX kit from RapidAir is going to be the easiest and quite competitive price-wise. I looked at 1/2 inch Type L copper and that's SERIOUSLY expensive. Close to $30 a stick for 10 foot sticks!

@Jim - One man shop, one tool at a time. Your point about the 1/4" connector is well taken. The biggest air hog in my inventory is the blasting cabinet. Most often used tool is a die grinder which also uses a fair bit of air.

Depending on how badly the basic distribution plumbing and the furnace deplete the shop fund, I hope to build a multi-loop copper pipe air dryer.

 

[RC4MAN]

Use 3/8" QD couplings

 

[kshansen]

Another idea I have heard of is to plumb in a loop. In other words put a tee at the outlet from the tank or air dryer and run piping all the way around the shop and back to the tee. This is suppose to prevent some of the loss from the lines and depending on the size and layout of the shop may only cost a couple sections of tubing.

 

[Jim]

Another idea I have heard of is to plumb in a loop. In other words put a tee at the outlet from the tank or air dryer and run piping all the way around the shop and back to the tee. This is suppose to prevent some of the loss from the lines and depending on the size and layout of the shop may only cost a couple sections of tubing.

The main reason for an "extended loop" is to allow more time (and surface area) for the air to cool..... dropping it below the dew point... allowing more of the water vapor to precipitate out and drain into the water traps.

 

[GLJ]

The loop is also done for air delivery if you have multiple people/machines using air. Usually in factories it will be rather large pipe. 2+ inch. Correctly design is to come out of the top of the header. 90, 90 down with a drip leg at the bottom of the drops. Also the header will not be level. It will slope downhill from the compressor room with a drain leg at the lowest points.
As DE said 1 man shop. One tool running at a time.
Same for me. I don't use a lot of air so this works. Biggest air user is my bead blast cabinet. Crude but effective.

 

[mike in idaho]

My 3/4 inch line runs from the compressor up to the ceiling then runs to a wall corner (about 15 feet away) with a line going down to a drain valve, almost to the floor. About halfway up the wall is a branch teed in, with a line running back up to the ceiling at a 45 degree angle, and running back down to the air drier mounted near the compressor. Running the line over to the corner, with the return branch pitched uphill seems to catch most of the moisture and oil before it gets to the drier.

 

[Grimly]

I hope to build a multi-loop copper pipe air dryer.

I used 1/2" copper and PEX with compression and push-fit, with the idea of creating an air ring main around the ceiling. The ring's not complete yet, but it works quite well as is.
For drying, I made a coil from 1/2" copper about 3ft high.

Some other parts of the system, with drops and drain points...

This is the main drain from the cooling spiral.

On this last one, you can see where I plan to extend the ring main to the left.

It's all fed from a FIAC 150L 3HP comp, with the option of connecting another 60L 3HP comp in tandem when I eventually get around to doing some blasting.

 

[FLEA]

 

[Jim]

I made loops from 1/2" copper tubing with a common drain valve at the bottom. Every outlet has an additional regulator/water separator. The copper was on hand. If I weren't so damn cheap I'd have made loops all the way across the wall. Still... it does a good job. In order of most water drained, the tank has the most... the copper loops are next, and the separators usually have very little water. No problems at all with the blast cabinet in the next room... always stays dry even when I get a full pint out of the tank in an hours use.

 

[Downeaster]

Here's what I came up with. About half from bits and pieces I had laying around, the other $100 worth from Deep Homo.
One ten foot stick of 3/4 copper was $35!

Air in upper left, air out upper right, drain via 1/4 turn ball valve just out of frame at the bottom. I see the bottom is a bit cockeyed, come from working on a 24" bench.

EDIT: Someone on another board pointed out a design error. I need to add two valves on the bottom loop to isolate it, otherwise the air will take the shortest path - down the first leg, across the drain loop and up the last leg. Doh.

 

[RC4MAN]

There are times when I think that you're all speaking in code and really building Stills

 

[Downeaster]

There are times when I think that you're all speaking in code and really building Stills

 

[Xs650911]

I'm thinking 3/4 PEX and a RapidAir kit for about $200 that has 100' of line and enough components for 3 drops.

Questions:

1. Do I really need 3/4 or will 1/2 do? 1/2 is cheaper but I wonder if it will move enough air for a small blast cabinet and occasional use of air impacts and ratchets.

2. Kit, individual components or a combination? I'd like to add a ball valve at the compressor and make provisions for a drain leg at the compressor as the first run will be about 6 feet vertically to get out of the compressor room.

3. Is there an affordable (sub $100) air drier that actually works?

4. Where should the air dryer go in the system - Right at the compressor or just before the drops?

5. Regular PEX or the PEX-AL-PEX stuff?

I've used the "hot n cold" cvpc plastic water line. Read on it and see what the psi rating is on it...plenty. Use 3/4 it's worth the extra volume but in the end you have to have a compressor and tank big enough to support the bigger line or it don't really matter how big the one is. I'd run 3/4 as much as I could.