Water in compressed air - again

[Gary McNair]

My 60 gal upright air compressor is making water in my lines again. I use the compressor often for painting and small air tools. I drain the tank regularily - weekly/daily or sooner if required. I have purchased many different types of inline dryers over the years but haven't been happy with any of them.
I'm looking at inline dryers that use a replaceable desecant. Has anyone had experience with this type of dryer?

[David Christopher]

Gary, we had driers like that on some of the ships that I was on and they were expensive..at home I use a second air tank ( 10 gallon ) in line after the primary tank..I cut it open and put baffles in it and it seems to work good...no more water getting in the air lines

[Ted Jay]

Gary,
Where in-line have you placed your water separator? IMO it should be located at least 20 feet away from the compressor, it should not be located at the compressor air outlet.

It would be best to run black pipe for that twenty feet or so to give the air in the line time to cool down after the compressor tank. When the air cools down is when you get the condensation and then the water separator will be able to do it's job better.

You can spend upwards of $350 to $500 for a 3 or 4-Stage Desiccant Dryer System, or you might want only a Coalescing Filter Can which runs about $25 to $30 bucks... or a Water/Oil Trap.
How much money you want to spend?

If your doing high end paint jobs on vehicles you might want the best, or start using water based finishes!

Good Luck,
Ted

PS: I am not a professional.. but I did stay at a Holiday Inn Express for 6 months while out of town on business.

[Scott T Smith]

Gary,
Where in-line have you placed your water separator? IMO it should be located at least 20 feet away from the compressor, it should not be located at the compressor air outlet.

It would be best to run black pipe for that twenty feet or so to give the air in the line time to cool down after the compressor tank. When the air cools down is when you get the condensation and then the water separator will be able to do it's job better.

+1. Following both of Ted's recommendations should solve your problem. Another thing to do is to route your air lines UP first from your main trunk lines, and then downward. That helps keep any moisture in your main trunk line. Main trunk lines should be sloped with a water drain at the end.

[Gary McNair]

Thanks - it's all coming back now -I'll incorporate those ideas.
Habor Fright has an automatic tank drain that drains tank water based on pressure in the unloader line. Some plumbing involved but it looks like it will work.
Anyone using this?

[Steve Jenkins]

Thanks - it's all coming back now -I'll incorporate those ideas.
Habor Fright has an automatic tank drain that drains tank water based on pressure in the unloader line. Some plumbing involved but it looks like it will work.
Anyone using this?

When I bought my 7-1/2hp IR it came with that type of tank drain and it has worked fine for about 6 years so far. the other thing I did was mount an aftercooler to the wall near the comp. It works like a car radiator. the air flows through the unit and a fan blows across cooling fins. It brings the air down to ambient temp. I have a moisture trap right after it.

[Jason Raksnis]

Try the desiccant dryer at harbor freight. Its only like 40 bucks and acually works really well. I have a 80 gallon compressor and was getting some blemishes in my finishes. So before i went and spent several hundred dollars on a better dryer i saw this one at HF and thought i'd give it try. I also bought an automatic tank drain and between those two things I have no more water in my lines. Although i have a nice 3 stage filter from SHARPE and an after cooler installed i really think the desiccant filter help out alot

http://www.harborfreight.com/cpi/cta...emnumber=97686ed

[Bob Slater]

I have recently purchased a Plasma cutter and the folks from the welding forums swear by Motorguard filters. (looks like a toilet paper roll) You can get the filters with housing from Amazon for a good price. I would only use this filter as a final stage, near the paint gun. Plasma cutters want ultra dry air.

[Gary McNair]

Appreciate all these replies. Looks like there are several good methods which could be combined to finally get rid of the water. BTW, I painted cars several yrs ago and used the little disposible inline filter at the gun. Guess that's what finally saved my - you know what!
Gary
Napa, CA

[Anthony Whitesell]

I have one. I had to swap the black plastic line out for copper (it kept melting when hooked to my 30 gallon Craftsman upright). It was working great but after 7yrs it's starting to leak. Luckily they cheap enough through HF not to cry to much when I finally replace it.

[Matt Meiser]

I have the Harbor Freight drain valve which I also need to replace. Mine lasted about 5 years which is like $3/year. Like Anthony, I installed it with copper line instead of the included plastic (but I did it right away because I didn't trust the plastic--never thought about melting.)

My piping is copper, installed so that it drains toward the far end which has a drip leg with a drain. I have all the drops plumbed so they come out of the top of the trunk line. And each drop has its own filter-regulator unit. I've never had any moisture issues even on humid summer days, except maybe with my plasma cutter.

I also have one of the Motorguard filters mounted on my plasma cutter's cart. I have a disposable inline desiccant dryer after that and it lasts a long, long time now. Before it would only last an hour or two of use. But since its an occasional use tool for me, that also could have been due to ambient moisture in the air when there was no hose connected. I keep a cap on the inlet hose now.

One thing that I've seen guys with plasma cutters do is build an intercooler or aftercooler for their compressor from a length of copper tube. The idea is to drop the air temperature and cause the moisture to condense in the tank where it should sit harmlessly at the bottom until drained. Harmless if you drain it, that is.

Speaking of the tank, yours does have the air outlet somewhere near the top, or at least the middle, right?

If its a real problem, you could look at getting one of the refrigerated dryer units.

[Gary McNair]

Thanks Matt
Yes the tank outlet is about 2/3rds of the way up from the bottom, obviously on the side. I've learned a lot from this post including a refresher on some things I had forgotten about.
Here's a question - if the compressor is in continuous use like using a DA sander, water will build in the bottom of the tank. If water begins to come out of the DA exhaust, is this the water swirled up from the bottom of the tank or?
Gary

[Steve Clardy]

I have the IR auto drain on my compressors.
$200.00 valve from Ebay that cost me about $75.00

Then I have a water seperator mounted at my air supply hookup on the wall.
I also use the little disposible filters that are attached to the spray gun.

No water problems.

[Troy Donson]

Just for giggles I am going to try and explain this. Please don't take this as "gospel" but what I have learned in 30 years of being a mechanic around alot of air tools...

Again, just for giggles: Assume your relative humidity is 25%. You are sucking that air in and then compressing it into your air tank. Now you have alot of air and water vapor in the tank. As the compressor is squeezing the air, the water vapor "drops out" and collects in the bottom of the tank. That's because the air under pressure can not tolerate as much moisture (you can not compress a liquid like you can a gas).

As you release air from the tank into the air lines, the water flashes intp a vapor again because of the pressure differential as the air moves out of the tank. As it then hits an even lower pressure area like the outlet of your tools, you have a "fog" effect and if the air/water density is heavy enough you can actually have liquid water blasting all over the place.

A good way to illustrate the effect is looking at the "water traps" in some auto shops. Next to water sensitive equipment, you will see a "expansion type" water trap. The less expensive ones are simply a glass/plastic bowl that allows the air to expand and drop it's water as it passes through. The more expensive units may have a bowl and then a desicant afterward. Then there are the refrigeration style units that cool and then seperate the water from the air...

I know I am really just touching the tip of the iceberg here, but hopefully you get the gist that a good seperator/filter as close to the compressor as possible and another as close as possible to the tool being used will prevent alot of headaches with water and oil (if you are using a sump style compressor) coming out your tools.

Hope I made some kind of sense...

Troy

[Gary McNair]

Troy
Thanks for that explanation. Interesting physics! I am getting a lot of water out of the exhaust of my tools. I always suspected the water collected at the bottom of the tank found it's way up to the tank outlet.
You mention the first attempt at water collection should be made close to the compressor outlet. Others have mentioned a run of at least 20' should be made in order to allow some cooling prior to intial drying. What has been your experience?
I am getting ready to install my new system. I'll be using copper and need to be thrifty on the run lengths
Gary