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Shop Air Dryer, DIY suggestions?

Freemasm

Well Known Member
Anyone have some DIY shop air dryer suggestions/experience they can share? Lots of postings/tutorials/YT vids out there. Wondering what some of you have tried that did/didn't work well. Let me know. Would like to save some money but in the end, it has to be effective. FL weather sucks related to tool life. Would also like to paint at some point, probably adding a small. temporary, in-line, desiccant dyer.

Your suggestions and experience are appreciated. Thx.
 
I’ve seen PVC used effectively and the cheap, large diameters would help water drop out. Even though it’s rated for the pressure, unlike metal a rupture has particularly bad consequences.
 
It's about cooling the compressor outlet air. If you want small and temporary, copper loops in a ice tub. The permanent solution is about 50 feet of standard steel pipe run around the shop perimeter, with drain drops at intervals. Take paint air from the last drop, tool air (with lubricator) at the next to last.
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best photo I have

you can see the five runs of vertical black pipe thru the back glass. there are a total of three drains, one at the bottom of each loop. the first drain catches most of it but they all catch some. I catch more drain water
in the Winter.

and as Dan mentioned, for painting, I also used a cold water bucket with loops of hose in it before the vertical pipe dryer.

I painted this aircraft in the Winter and didn't have any water issues.

IMG_20200929_172241(1).jpg
 
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Don't forget to drain the compressor tank itself.

Funny story. A local farmer bought a new compressor to replace his tired older upright one. Then we found that the old compressor tank had about 25 gallons of water in it. It was never drained.:eek:
 
@DanH. Yes you've got to cool it but getting the velocity down helps the drops that form fall out but then the tubulation is down so the overall Q drops and the dance goes on. Haven't calculated a sweet spot for surface area versus inner velocity versus turbulation. Maybe right at an Re of 3000 for max flow? Of course, you're rarely at max flow. I like the ice (or even water) cooling idea. Maybe a valve in one of the low point cross-overs to isolate and then use the local drains to attach a cooling loop. That's a nice looking shop BTW.

@Vince. In humid AF Florida, I don't cycle drains. I leave them generously cracked and they weep/run continuously.

Maybe one large bore vertical section plus some brass runs. Don't know that I have enough interest to do an optimization calc on a Friday.
 
This kinda doesn't answer the question directly except it works.
Get on Craigslist/Market place and buy a second air tank, say an 60-80 gallon. Put it in line with your system and get the larger volume and cooler air. The less the compressor runs the dryer the air will be
I have an 80 gallon outside piped in to an 120 gallon then to my air system. Never any water concerns. love the 200 gallon storage. I paid $100.00 for the extra 120 gallon tank.
Now for DRY air to paint with I have a actual dryer inline just for super dry air. All hoses after air dryer are dedicated to painting so NO crud oil or anything is introduced it the paint system.
Hey maybe it is over kill but I've painted enough stuff and did a poor job because of bad air.
Art
 
pvc is rated for water pressure. Air pressure reduces rating substantially. I have seen it explode at 100psi and the shrapnel isn't pretty. Fittings expecially are only rated to 15 psi air. Buy a harbor freight dryer with a 20% off coupon. Its what I do for my cnc plasma table.
 
pvc is rated for water pressure. Air pressure reduces rating substantially. I have seen it explode at 100psi and the shrapnel isn't pretty. Fittings expecially are only rated to 15 psi air. Buy a harbor freight dryer with a 20% off coupon. Its what I do for my cnc plasma table.

Unrelated, but Harbor Freight has gone to shiat.. Haven't seen a 20% off coupon in months.. Finally unsubscribed from their mailings and texts...
 
My main compressor connects to a 12ft vertical loop of 5/8 aluminum tube, then to a 5gal expantion tank, then to the usual filter/regulator. It works perfectly. I get clean dry air even in the Texas humidity. Once, When I was painting the plane, it started raining. Even with that, my air was dry. I drained a gallon of water out of the tanks after that session, they started dry...
 
Aftercooler & Copper Lines

DIY aftercoolers work really well if you don't have a reason to run lines around the shop and just want something to cool the air right at the compressor. If you are going to run pipe anyway because you want more drops for air hoses, then you can probably get away without an aftercooler. You just need enough pipe to let the air cool so the water can condense out. Of course with either method you need vertical drains.

Compressor tank size makes a difference as well. Smaller compressors will push more hot air based on the demand and larger tanks will let the air cool a bit before you end up using it. I currently have an 80 gallon tank and about 25-30 feet of copper line, ending with a vertical drain, water separator, and then a regulator/filter. So far, I've had virtually no water make its way to the final filter at the regulator. Once I get ready to paint, I'll probably throw an inline desiccant filter into the mix as well just to be sure.
 
I have a 20 gal compressor connected to copper lines that run with a slight up-hill, a moisture trap and valve at the low point. The copper lines run along the ceiling with the slight slope until a big down to bench level for the hose connections. There are fancy air/water separators just before the air hose connections that have yet to see a drop of debris or moisture in them. I have an oil lubricated compressor, so I'm sure they capture some oil, but are otherwise spotless.

After a day of heavy air tool use, there's a decent amount of moisture that comes out of the air line drain valve and the air tank drain, but still nothing in the filter/separator.
 
When I bought my HF pneumatic riveter for pop rivets it was terrible and pulled maybe 10 rivets before it broke. Threw it away. But I did get from the back of the manual for it the best drawing I've seen for how to setup a shop air system. It clearly laid out a copper pipe system, with a regular drop by length, a drain at the end, and takeoffs for air supply points that came UP from the pipe run so the air you take has to go up and 180" to come down to your work from the piping run. Water doesn't want to entrain on that up-leg of the air.

Before that I had water everywhere when I ran a die grinder. I put that in, with the run going in a circle around my 2-car garage, and presto! no water in anything at all except the drain line I purged occasionally. Their advice was the best $30 of anything HF ever sold me - except the cheap paint guns.

In my hangar shop I ran PEX with a slightly higher slope (less heat transfer) and it has been flawless.
 
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