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Old 05-15-2008, 12:04 PM
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Removing moisture from commpressed air

Hello everyone,

I am having problems with air in my lines while sandblasting and went to the TP Tools place to see what I can do about it. The guy there told me I will need at least 25 feet of line to cool the air and showed me a diagram in their catalog that shows to run line with a riser and drain line. Just want to make sure this is accurate info before running line all over my garage.

My current setup is just a regulator/filter of the compressor the the quick connect fitting and this is not working.

Thanks for any advice

Karl

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Old 05-15-2008, 12:27 PM
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compressor drain

I have an auto drain on my 50 gal tank and i still get water. the lines slope and run 60 ft to the sandblaster ... a drain at the end of the line and all outlets are on a soldered U that goes up out main line then down to the quick fittings ...on my plasma cutter i have a motor guard filter and some clear plastic desecant units...moistuer will ruin plasma tips...in commercial shops where i have worked they had refrigerated moisture dryer. HF sells one but i don't know how wel it works..

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Old 05-15-2008, 02:58 PM
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Welcome

Actually 25' is not enough if you plan to paint or use a sand/media blaster. You could run a conventional set-up and try to run that much line around your shop but a better way would be this very ingenious design by one of the guys here. This is a fairly simple space saving design that looks as if it would work really well and indeed the word from those who have tried it says that it does just that.



Airline Piping Question


There has been a lot of discussion here about this subject so if you search "airlines" you should be able to turn up a lot of info, some of it quite recently. Setting up a good pipping system is extremely important but it does not have to be complicated nor expensive so do that search and if you still have questions someone will be here to help you out.
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Old 05-15-2008, 07:48 PM
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I have a TIP cabinet and have had good luck by having a water trap at the compreser and also one at the air fitting at the cabinet. Because my cabinet is across the garage from my compreser, and is only used once in a while I just run an rubber air hose between the traps. Even with the trap at the compreser the one at the cabinet does collect a lot of water. This setup keeps my cabinet working nice and dry.
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Old 05-16-2008, 08:08 AM
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Quote:
Originally Posted by Henry the 32nd
I have a TIP cabinet and have had good luck by having a water trap at the compreser and also one at the air fitting at the cabinet. Because my cabinet is across the garage from my compreser,

Even with the trap at the compreser the one at the cabinet does collect a lot of water. This setup keeps my cabinet working nice and dry.
The trap at the compressor is almost wasted effort and they should not be placed there. If you look at how a water trap works it is easy to understand why they do next to no good when used close to, or on, the tank. When the air first exits the tank it will be hot and most of the water will be in vapor form so it will pass right through the trap because the trap can only separate liquid water and not vapor. As the air travels along the line the pipe acts as a heat exchanger radiating the heat from the air allowing the water vapor to condense into liquid water that can then be removed by the trap. In order for a pipe system to work properly the water trap needs to be located as far as possible from the compressor and the air needs to be carried by a metal line so it will have a chance to cool. Copper works best but Iron, either black Iron or galvanized, does just fine also but a rubber hose will not work well at all due to it's insulating qualities. PVC is also a poor conductor of heat and does not work well at all for moisture removal but PVC should NEVER be used anyway because it is VERY DANGEROUS in spite of what some might say! But that is a whole different subject. Some will argue that the trap does work ok when attached to the tank because it will catch some water but about the only time it will do much good when that close is when the air is first drawn from a cool tank and the compressor has not had a chance to heat it. If only relatively small amounts of air is being used (or at the beginning of a heavier use) then the air will not be hot yet and at that point only will any real amount of water be removed. These piping systems are not just a neat way to get air from point A to point B they are a very important part of any air system and if improperly done the whole system becomes a major headache! Each part of the system has an important job to do and although the compressor is the heart of the set-up the other components, especially the piping, are necessary for a properly operating system in order to have clean dry air.
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Old 05-16-2008, 11:53 AM
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To emphasize what oldred has to say - don't even consider PVC. I did before he and several others here suggested that it was a bad idea. I pulled it apart - and for whatever reason, every joint fractured. I installed a copper line and while it for sure isn't fancy, really did the job. I used about 50 feet of 1/2 line, a valve on each vertical line as well as two water traps. One trap, a Harbor Freight really will only knock part of the water as well as and dirt out then it feeds into a good Sharpe trap then into the regulator. So far, absolutely no water carry over. I painted a car last fall during a fairly humid period - and the traps plus the valved vertical runs knocked it all out. The trap at the compressor - unfortunately, is there only for looks. Remember how humid it gets when the outside temps get up there? That's exactly the same with a compressor. Heated air will hold significantly more moisture then cool air so the long copper line works as a heat sink. If you wanted to, you could even run a loop of copper air line thru a bucket/barrel of cold water and traps would work even better as water droplets come out of suspension and can be "knocked out" by the trap easier as big drops instead of small ones.

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Old 05-16-2008, 03:04 PM
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Quote:
Originally Posted by Irelands child
TIf you wanted to, you could even run a loop of copper air line thru a bucket/barrel of cold water and traps would work even better as water droplets come out of suspension and can be "knocked out" by the trap easier as big drops instead of small ones.Dave W
This most certainly does work and I have seen it done several times. A good pipe/trap system is still required to catch the condensed water but a coil of Copper in a barrel of water with some ice added can work almost as good as an expensive refrigerated dryer, for a while anyway. This is easy to set up and for painting or short sandblasting sessions can be just the ticket if humidity is a problem and the job requires really dry air, probably not something most people would want for a permanent setup but for those special occasions it can work really well.
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Old 05-18-2008, 12:25 AM
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Heres this if it will help. http://www.1969supersport.com/draw1.html

Rob

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Old 05-19-2008, 07:26 PM
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Look, the length of hose or piping is immaterial....the moisture will be carried with the air and your ****ed no matter what...

you have only two choices to make the blaster work right:

1) a water trap at the air compressor and then run through a refrigerated air dryer.....in my shop, thats what I use....and it works excellent!!

2) you can do what the professional mobile sandblast companies do and buy a large canister type 'dessicant' dryer....that uses dessicant crystals....

dessicant crystals are not cheap...but can be dried out in an oven and re-used.....

without either of the above, you will have a constant headache from moisture!

PS: TIP>>>> step up to a larger nozzle size too! you'll blow thru sand quicker but they dont clogg as easy from moist sand.....

also , if you dont use your blaster a lot, dump it out after you use it because moist sand will corrode out the tank....
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Old 05-19-2008, 10:10 PM
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Oldred:

I seem to recall someone building their own (refrigerated?) air-dryer system out of an old A/C condensor or more?

Do you (or anyone else) recall seeing it?
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Old 05-20-2008, 09:28 AM
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[QUOTE=dustyrustee]Look, the length of hose or piping is immaterial....the moisture will be carried with the air and your ****ed no matter what...

you have only two choices to make the blaster work right:

1) a water trap at the air compressor and then run through a refrigerated air dryer.....in my shop, thats what I use....and it works excellent!!

2) you can do what the professional mobile sandblast companies do and buy a large canister type 'dessicant' dryer....that uses dessicant crystals....

dessicant crystals are not cheap...but can be dried out in an oven and re-used.....

without either of the above, you will have a constant headache from moisture!

/QUOTE]


Dusty, I have to disagree on both points- the length of the pipe makes all the difference in the world and a trap located at the compressor does little good and the reason is the same for both cases, this is well known engineering info and not just an opinion. It is standard procedure to run pipe in such a manner and of the proper material that the air will have a chance to cool before it reaches the separator otherwise the water will be in vapor form and pass right through. If you use a short pipe or locate the trap right on the compressor the air will be hot when it passes the trap and the vapor will then pass though only to cool and condense in your air hose and as it exits into your tools. If on the other hand you use enough metal pipe, preferably at least 50', then the pipe will act as a heat exchanger allowing the air to cool and the water vapor to condense into liquid water that can then be caught in the trap which must be located downstream on the line after the air has had a chance to cool. This is the reason that Copper pipe works somewhat better than iron when only short sections can be run (less than 50') and why PVC pipe does so poorly at removing moisture. A properly run metal piping system with a good trap/filter is usually adequate for most home or small shop systems unless a huge amount of air is being used.


66, The system you mention is not actually refrigerated but it does use an AC evaporator core. This can be used instead of, or in addition too, the long lengths of pipe required otherwise. In the case of the AC core system you would simply run the hot air from the compressor into the AC core and force cooling air through the setup with a fan then attach the water separator to the line after the compressor air exits the AC core. The system I first mentioned here some time back has since been modified to box in the AC core and use a fan to pull cooling air through it instead of simply placing a fan behind an open core, this seems to work even better. This could be an excellent alternative to using a long air line but I have been hesitant to suggest doing it because of possible hazards involved. It need not be at all risky but anyone considering doing this should first look at all the safety issues. Is the core in good enough shape to handle the air pressure? Are all the fittings installed PROPERLY? Is the AC core isolated from line vibration? (EXTREMELY important!) Done properly and with caution in mind this can work very well and in fact the system I mentioned works really well even powering a sandblaster, which is it's main use. This could even be cooled with water to make a very efficient setup that could rival (I said rival, not equal) a refrigerated system in performance but at a fraction of the cost, might be an interesting project!

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Old 05-20-2008, 10:27 AM
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Quote:
Look, the length of hose or piping is immaterial....the moisture will be carried with the air and your ****ed no matter what...

you have only two choices to make the blaster work right:

1) a water trap at the air compressor and then run through a refrigerated air dryer.....in my shop, thats what I use....and it works excellent!!
How do you think a refrigerant dryer works?

It's a series of heat exchangers, cooled by a refrigerant, to condense the water in the compressed air so it can be removed. Same principle as oldred's pipe system.
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Old 05-20-2008, 03:53 PM
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Removing moisture from compressed air

We use a dessiacant drier, not cheap but it works fine.We have it set up so we use it only for painting or blasting,regular air goes thru 2 traps mounted far away from the compressor. I know some one will give me some flak on this as it is my way and not someone elses.I dont much care,'cause we do everything WRONG. Our entire system is plumbed with HOSE.
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Old 05-20-2008, 08:40 PM
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removing moisture

I live in the humid South Texas area and the metal pipe system works great. I started with a 20' piece of 3/4" galvanized pipe and followed the layout on the TP tools site. It worked great up until I went to a bigger higher volume compressor and a larger blasting cabinet. Now it works great most of the time, but in the middle of summer on high humidity days after running the cabinet for a long period I start to get moist sand. I'm in the process of doubling the length of pipe now. If that doesn't do it, I'll add another 20' section. I don't even have a water separator,filter or dryer. Just the pipe and a drain.
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Old 05-20-2008, 09:13 PM
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Put that extra pipe in then put some of these f-88's in, http://www.1969supersport.com/draw4.html and your days of moisture in the sand are over.

Rob

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