Replumb air lines question

[Shopdog]

I am replumbing my air lines tomorrow. I want no water vapor in my paint area so heres what I am doing.

Running 25ft line across the ceiling in my shop to the adjacent wall, at the wall I will have a 5ft drop for water relief, at the 2.5ft mark will be my inlet at the top will be my outlet going to various work stations, at the HVLP I will have a disposable dessicant attachment.

So, my question is, how will this fare to help rid my paint of water vapor. Right now I have no obvious water but summer humidity is not yet in full swing, so I am trying to stop a future problem. No, I cannot afford an air dryer, so that is out of the question. I am trying to minimize the cost so I can add to my tools.

Spraying items will be few and far between.

Thanks for any suggestions

Searcher

[Leon]

You want water filter of some type as close to the sprayer as possible. The water can condense anywhere in the air line including the hose connected to the sprayer. The more the compressor runs during a spray session the more condensation will be a problem from the heated compressed air.

[Leon]

Exactly. A good point to start. You have to remove all moisture to keep it from coming out of the air lines. Moisture moves with the air and the greater the difference in the hotter compressed air temperature than the outside temperature the bigger the problem with immediate condensation as it cools and when it exits the hose.

[Lew Hodgett]

I've posted this before, so this is a short hand version.

Buy a full 20 ft length of 2" black pipe, have it cut and threaded in 5 ft lengths.

Assemble using 2 run x 2 run x 3/4 side tees and 2x2x2 end fittings to form a 20 ft run.

Hang assembly overhead with 1/12 pitch and 3/4 side fittings of tees pointing up towards ceiling.

Install two (2), 3/4" street ells to form a "U" shape take off for air hose connection. (This forces the air to first go up, then over, then down and is a natural water trap)

Install a drain petcock in low point.

What I have described ism a very basic distribution that will eliminate

90% of your water problems.

Supporting engineering documentaion available, I'm just to damn tired to post it tonight.

Good luck.

Lew

[Edwin Pawlowski]

Sure they do. The humidity is the amount of water held by the air. The higher the humidity, the more water vapor in the air, the more condensation. The longer the run, the greater the chance of the vapor condensing before it gets to the point of use. Industrial dryers cools hte air using a refrigerant so the moisture condenses out at that point and is not carried in the system. If you have a 100' foor run it is more likely to condense the moiusture than a 5' run.

Another factor in the moiusture at the point of use is the tank, and when it is filled. If you start the compressor, bring the system up to pressure, then just leave it, the moisture will probably condense int he reciver and can be drained. If air flow is immediate and of large use, it is more likely to be carriesd out. Right now, our compressor air temperature is 275 degrees. By the time it gets to the chiller, it is down to 100 degreess, then it h its a 40 degree thermal mass to condense out what is left. If the flow was not continuous, it could condense in the receiving tank, but with a use of 600 to 70o cfm, that does not happen.

Perhaps. Every system, every use is different. Your method takes a large portion of the water out, but it may not work as well for a different setup.

[Charley]

A few years ago I was having a lot of moisture problems with my compressed air system. A friend suggested that I buy a special filter that uses a roll of toilet paper as the filter media. I bought one at the local auto paint supplier for about $30 and I connect it in the air line to the spray gun or other air tool whenever I absolutely can't tolerate any moisture. A new roll of paper (cheap stuff - you don't need Charmin) before each day's use (remove it after use) and it has never failed to provide the dry air that I've needed.

[Mike Marlow]

condensation.

I don't argue with the principles you explain Edwin, but with the real world occurrances. I do a lot of spray painting and I'm not sure what your experiences are, but mine are as I described. I live in Central NY which enjoys a reasonably high humidity and as I stated in a previous post, I have repeatedly painted an entire car with no moisture problems by following what I had suggested to the OP. Perhaps your experiences differ? Certainly the OP is not going to use as much air as I do when I paint a car, making him no more susceptable to moisture issues than me.

For the application in question it will work well. Moisture build up is reasonably predictable and some simple precautions will indeed work. Again - he's talking about a lot lighter usage than what I put my system through, so he'll see less of a moisture problem. Of course - assuming a reasonable compressor to start with, but even smaller ones will perform very well for a long time. I used to shoot cars with a Sears 5HP/33gal unit. With that compressor I used to drain the tank anytime I changed over what I was shooting. Shoot primer - drain the tank. Shoot base coat - drain the tank. Shoot clear - drain the tank. I never had a problem that lead me to this ritual, but because the system was so small I took the precautions just to be safe. It was probably a bit of overkill, but it didn't take too long, and it didn't cost anything to do it.

[Shopdog]

I listened to what everyone said and this is what I have done.

I ran 25ft across my ceiling added a water/particle trap. the intake is

2.5ft below the output, hoping that water will run down before going UP to the outlets. I sealed the pipe with pipe thread sealant instead of teflon tape. Everything is leak free and I now have 4 air stations plus room for 2 more if needed later.

Thanks again

Searcher

[Edwin Pawlowski]

I don't have much experience with spray painting, but I do run a 150 Hp and a 75 HP compressor that feeds air operated controls on machines. The 150 runs 24/5. The 75 used to be the "big" compressor, but now is molstly backup. The controls and machines (plenty of air operated pistons) don't work as well when moisture is in the air. A machine can have as many as 50 air operated devices times 15 machines. We have a mechanical dryer that can handle 1200 CFM. Thre are two receivers with automatic drains before the machine. Take the dryer out of the system, you can shoot water from an air gun. We also have an oil separator. Real world enough?

[O D]

Now what? Are you going to break the pipe dope seal every time you want to get water out? If your not doing that much finishing work and cannot have moisture in the finish then you are going to have to bit the bullet and get a drier ( refrig ) or maybe nitrogen, How much of a problem if you have to re-finish an item is it? You don't want moisture and you don't want to buy the equipt to remove it.....well houston.......we have a problem!!!!!! Call a welding supply house and find out how much for a tank and see if it will do the work for you. Don't know of any other cheap air supply to try. Good luck.

[Shopdog]

No, I think I had enough common sense to install a valve complete with 1/4 tube running to a drain. Last year I had water vapor problem but it mainly occurred when I was sandblasting a large item.I would occasionally get water dripping out of a tool too, but the compressor was set up in a basement and really had no run to condense the water out. I have since bought a new house and have set up the shop and I just wanted to help get a handle on any water problems that I may have here.I keep in touch when the humidity rises the I'll go out and sandblast something, see how my efforts have paid me.

Searcher

[Mike Marlow]

Yeah baby! That's what I'm talkin' about! Now that's a man's toy. I thought you must have been referring to usage and duty cycle similar to what you just described when you first posted about my comments. Very real world... just a tad different world than what we're working in.

BTW... have you considered one of those Harbor Freight sniffers for the

150HP compressor?....