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vectorges
04-24-2007, 07:08 AM
I noticed last night when I drained my air compressor that the water coming out was a bit red. Is there anything that can be done to keep the inside from rusting out? Seems like a little something added through the bottom bleeder hole could coat the area. Phosphoric acid? Rustoleum? Obviously it needs to harden before using the compressor. Or will the rust itself just form a protective layer?

mike6845
04-24-2007, 08:57 AM
There is always going to be heat build up when you compress air and condensation resulting when the air cools off inside the tank. It is this condensation in the form of water which will settle in the bottom of the tank and form rust. The only effective method to minimize all this is to install an automatic drain valve and let it blow off the water build up. I've got a solenoid valve on my I.R. compressor for this purpose. You can find them on E-Bay for 50-100 bucks. Your other option is to install a manual valve and blow off the water manually.

metallurgy
04-24-2007, 10:03 AM
http://www.everyaircompressor.com/asp/show_detail.asp?sku=CHP1352&refid=FR79-CHP1352

this keeps the water from getting in...

old blue
04-24-2007, 10:15 AM
y'know, they do have water filter things that go on compressors so water dosen't get in them. they take the moisture out of the air. There is one on the big compressor here...:

http://www.everyaircompressor.com/asp/show_detail.asp?sku=CHP1352&refid=FR79-CHP1352

Is it worth 100$?

That is an outlet filter.. doesn't do jack with regards to keeping anything atmospheric from passing thru the pump into the tank.. it only reduces moisture and contaminants entering the hose.
Additionally, if you're spraying paint, you also need another trap at the gun end of the hose.

As previously mentioned the only practical method, for most, is draining the tank condensate.

Roospike
04-24-2007, 03:09 PM
Auto drain works best ( as so you dont forget to drain ) I have the Ingersoll Rand auto drain.

You can put a a elbow with a pipe and a ball valve at the end to drain , not only is it easier to drain the tanks, the water sits in the pipe/drain and not in the bottom of the tank.

Roospike
04-24-2007, 03:13 PM
http://www.everyaircompressor.com/asp/show_detail.asp?sku=CHP1352&refid=FR79-CHP1352

this keeps the water from getting in...


I have the Ingersoll Rand set up like this for the main air line and i also have the CH set up you link to on my plasma cutter with the extra air control / gauge . I also have the motorguard filter set up on the plasma.

JHCHOPPERS
04-24-2007, 04:00 PM
Auto drain works best ( as so you dont forget to drain...

We have one of these installed, works great...

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46960

Roospike
04-24-2007, 04:41 PM
We have one of these installed, works great...

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46960

With the Harbor Freight drains dont they have to get down to a lower pressure in the tank to open ? ( i cant remember for sure )

I thought i was reading of the plastic lines breaking on theses HF units . Any problems with yours JHC from plastic lines ?

Nickoli
04-24-2007, 09:28 PM
I thought i was reading of the plastic lines breaking on theses HF units . Any problems with yours JHC from plastic lines ?

I changed out the plastic line that came with the unit with 1/4" copper tubing when initially setting up...auto drain unit works great and keeps the water in the tank emptied. The valve opens and stays open up to 20psi and then opens and closes every time the compressor cycles.

Roospike
04-25-2007, 02:42 AM
I changed out the plastic line that came with the unit with 1/4" copper tubing when initially setting up...auto drain unit works great and keeps the water in the tank emptied. The valve opens and stays open up to 20psi and then opens and closes every time the compressor cycles.

So when the compressor is 175 PSI and drops to 150 psi and the motor / pump kicks on it will open/cycle ? ............. and for how long ?

I heard of the lower pressure cycle but didnt know they did in the upper pressure.

The HF web site dont say what max pressure set up for the unit is (for the auto drain)......... I know there electric air line dryer is for only under 150 PSI so it wounldnt work on the bigger boy compressors.

Roospike
04-25-2007, 02:47 AM
Op , I found it. ( right under my nose ) So i guess it not for 2 stage compressors and/or over 145 PSI .


From there web site:
************************************************** ************************************************** ******************
AUTOMATIC COMPRESSOR DRAIN KIT


Removes condensation without you having to give it another thought. Includes 1/4'' NPT street T, 1/4'' pet****, 1/4'' tube fitting x 1/8'' male NPT fitting and 8 ft. of 1/4'' 145 PSI polyurethane tubing.
Prevent the buildup of slime and tool-damaging particles
Extend the life of your compressor tank
Automatic clog-free discharge
High quality brass construction
************************************************** ************************************************** *******************

Hotfoot
04-25-2007, 09:48 AM
The HF one has to re-set at about zero pressure, then stays open (allowing water to be pushed out) until 20 psi, at which time it snaps shut. Mine has worked beautifully for about three years. the plastic line it comes with gets soft when hot (as in - near the compressor!), and blows off. I replaced that line with some black line the local Compressor Repair shop uses. They call it "Brake Line".
I ahve VEY little water get into the rest of my cobbled-up system. The first filter is one of the big blue and chrome HF units with the gauge on it, then 25' of iron pipe with two 24" drop tubes with ball vales at the end, then another twin jar type seperator/filter where the hose hooks in. Never any moisture problems.
A good test is to point a blow gun at your dry concrete floor from about 8 -10" away and blow. You should not get any moisture. Then, do the same to the palm of your hand.:)

JHCHOPPERS
04-26-2007, 10:47 AM
I thought i was reading of the plastic lines breaking on theses HF units . Any problems with yours JHC from plastic lines ?

We got our kit for $6.99 when it was on sale. All we wanted was the pressure value, for the rest of the kit you can either use it or make up your own with copper tubing.

whateg0
04-26-2007, 12:28 PM
I would think that the cooling systems that many people have put together or can be purchased would do a good job of not allowing the water to accumulate at all in the tank. I know that there are times when my compressor doesn't run for several days. During those times any water that has condensed and accumulated in the bottom of my tank (I know there isn't that much from one cycling of the pump) is just sitting there. If it goes through a series of cooling lines the condensate collects in a location prior to reaching the tank where it is likely to do much less damage.

At least that's my take on it.

Dave

TEK
04-26-2007, 03:01 PM
T
A good test is to point a blow gun at your dry concrete floor from about 8 -10" away and blow. You should not get any moisture. Then, do the same to the palm of your hand.:)

This is not really a good practice. Safety guys are always harping about it. Think about a piece of crap in the line piercing your skin and then high-pressure air blowing into the cut:eek
This is not a high probability accident but it does happen. In my 30+ yrs in the trades I met one guy that had it happen. His arm was a shriveled mess. Dont blow hi-press at bare skin.

enlpck
04-26-2007, 08:08 PM
I'v been half following htis thread, but everything I had to say had already been said to this point....

I second TEK on blowing air at your body. DON'T do it. Don't use a blowgun to dust your clothing, either. This is one of the most dangerous tools in the shop, mostly because the danger isn't recognised. Responsible for a lot of eye injuries, and it can blow debris into your skin, as well. I've know several people that have had crud blown into the eye, either by a blowgun or an air tool exhaust.

Several options:

In terms of keeping the reservoir (and air system) dry, the best thing is as much cooling surface prior to the tank as possible. A flex from the pump to a good run of steel pip is about as good as it gets. I have one compressor set up with 20+ feet of 1" prior to the first tank. Even on the most humid day, running hard, almost nothing gets to the water trap or second tank. More pipe would be better, but not worth the cost and space. Just don't want to leave low spots in the cooling pipe to trap water.

Another system has two tanks (need the capacity for heavy draw tools) and the first catches most of the water and does most of the cooling, the second still catches a bit. A bit of pipe at the drain to act as a trap leg gets the condensate out of the tank, and keeps the tank dry if blown down regularly.

A third system (ya, we have a lot of air. Many machines carry their own systems) has eight--yes, eight-- smaller reservoirs. Tight space and need capacity. They are in series to provide for cooling and trapping, and little water makes it past the second one. Still have a trap on the main line after the tanks for insurance.

Only one of the systems DOESN't have an auto-spit at the first reservoir. Noone have one past that... they get drained daily. Even with the auto, you should hit it by have once in a while, and open it wide. This gets a high enough velocity to free much of what sits in pits or in smaller drops away from the drain tap. It is also CRITICAL that the drain tap be at the low spot. Vertical tanks do this automatically. Horizontal tanks should be drained from a tap near one end, and tilted slightly to assist getting the condensate to the drain.

BKD
04-29-2007, 11:33 PM
Believe it or not, most of the rust will form in the TOP of the tank, not the BOTTOM.

When I made my BBQ pit out of a 50+ year old air compressor tank, I discovered that the bottom of the tank was in nearly perfect condition... all the rust and scale and stuff was coming from the TOP of the tank... it was an eye opener for sure, and not at all what I expected to see.

The oil from the compressor pump settles in the bottom portion of the tank, protecting it from rusting, while the top portion of the tank doesn't benefit from this "protective coating" like the bottom does, and thus is exposed to the high pressure air inside (of which 20% of it is OXYGEN...) and so it rusts.

Like I said, not at all what I expected to see, but that's how it was with the 80gal horizontal tank I made into a bbq pit...

whateg0
04-30-2007, 12:04 AM
Brian,
That may not apply to the newer oil-less compressors. For a oil-lubed compressor, though, I can believe that. Just a guess here, but I would imagine that the hotter, freshly compressed air containing the moisture also rises to the top where it contacts the cooler tank. So this is probably where the majority of the condensation collects initially, before it drips to the bottom. All the more reason to cool the air and collect the moisture before it gets to the tank.

Dave

Butch007
04-30-2007, 12:34 AM
I use these on my compressor tanks. Its not automatic or fancy, but it sure makes it quick and easy to drain water from the tank. Just a quick yank for a few seconds blows the water out the bottom and then back to work.

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=MBI&PartNumber=12103&Description=Air+Valve+%2f+Drain

enlpck
04-30-2007, 12:17 PM
I'v been inside several dozen of air tanks over the years, and have found that, though the top tends to have a good bit of rust and scale, the *damage* is pretty much on the bottom. The pits are what get you, where water sits. The oil really doesn't provide as much protection as you might think, unfortunately.

bill400
05-01-2007, 11:27 PM
I got tired of reaching under my homeowner size 110 compressor to drain the tank so I added some tubing and moved the drain valve up onto the handle. That way I'm more likely to remember and take the trouble to drain it.