Air Compressors and Blow Guns

[Tom Wesenberg]

This is a repeat of many years ago, but how many people drain their air compressor tanks of water that condenses inside the tank? Also change the oil every so often. I was in the basement on the computer several years ago and heard a loud explosion. My neighbor's air compressor just blew up because the tank was so rusty. When he gave me the remains I actually found that he had put a sheet metal screw in a rust hole so he could keep using it. This guy used to run dragsters and also ran a tranny shop, so you'd think he would have known better.

Last week my other neighbor put a like new air compressor out on the curb with a sign "FREE LOCKED UP". Luckily I was the first to see it and drag it home. What I found was the motor pulley was out of alignment with the pump pulley, and the belt came off. I dusted it off and painted the two pulleys and handle, which the factory likes to leave bare metal, which turns to rust. Anyway the compressor doesn't look like it has more than a few hours on it. I called my neighbor as soon as I got it home to ask him if it locked up from setting, or while it was running. He said he wasn't sure and it was one he got from his dad when he passed away. He said he got a new one and didn't care about his one. You'd have thought that he would have known the belt just came off.

I actually use one like this to do all my work including sandblasting. This will maintain 40 lbs. at the cabinet with the trigger pulled. If I was heavy into sandblasting I really would need to buy a larger two stage compressor, but this size works well for most of my work. I would never buy an oiless direct drive compressor. They are too noisy and wear out too quickly.

Also shown are two blow guns I bought. The one with the narrower pipe is from Harbor Freight and is junk which cost $4.99. I can blow more air with my mouth and a drinking straw than this piece of crap does. The other blow gun came from Fleet Farm for $3.99 and works great.

[DennisR]

I open my drain valve after every use and leave it open until next use, I just check oil level and top up if required and change the oil yearly.

[Bruce of MN]

I piped the drain port to the front of my new compressor to make it accessible, just a few nipples and elbows.

[George Miller]

Yes on both. My compressor is a 1953 that my Dad had. It is in need of a valve job, but still works ok.

[Tom Wesenberg]

Originally Posted by Bruce of MN

I piped the drain port to the front of my new compressor to make it accessible, just a few nipples and elbows.

Good reminder. I like to do the same and will have to buy a couple fittings to do it to this one.

I never drain all the air from the tank, but just the water. Actually a quarter turn ball valve (or taper valve like the Model A lower pipe uses) is much easier to use than the cheap drain valve most of these compressors come with, so I'll look for one of those also.

[Afordman31]

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I drain mine after using, I don't use it in the winter as my building isn't heated. I have a homemade one in my garage that I use if I have to air up a tire or blow something off.
I also have mine piped outside so I won't be sucking in primer dust etc.
Been working good many years.

[Vin-tin]

I put a small valve, elbow, and hose barb with a length of clear hose which I ran to the outside. I don't drain my tank as often as I should.

[ddweave]

I use an "automatic" compressor drain from Harbor Freight. Every time the compressor shuts off, it "blows off" a small amount of air through the tank drain. Once every couple of years I have to take it off and clean it - if it gets a piece of junk in it it will constantly leak.

http://www.harborfreight.com/automat...kit-68244.html

[pgerhardt]

Once they rust out on the bottom they drain themselves!

[aermotor]

I saw the results of a 50 gallon tank blowing off the bottom. The tank went through the roof and landed about 75 feet away, pop off was at 124 psi. - was not a pretty sight and no one hurt.

John

[Terry, NJ]

Mine is an upright 1947 American compressor that was given to me. My friend Kris was threatening his father to get it out of there or he was going to scrap it. I took it instead and promised his father (An old friend) that he could have back whenever. It's in good shape, But there are two 2-21/2" plugs in the side. I opened the bottom and took about 5 lbs of soggy rust particles out of the bottom. This kinda scared me and I lowered the cut off pressure setting to 90Lbs from 120Lbs. But from an old experience with hot water expansion tank that blew out the side of the garage........ It ain't necessarily the pressure that get you, It's the atmospheres! One atmosphere is 14.7lbs, two atmosperes are 29.4 and so on..This is why they test hydrostatically, because when a tank's volume is full of water with a very small airspace then you don't have that much airspace throwing metal around
the room. When it's all air, then you get a lot of expansion and it throws shrapnel in all directions.
Terry

[Fullraceflathead]

Harbor freight has a auto drain valve that I put on mine.
When the pressure gets low enough it opens to drain the water out completely then closes.

[katy]

I don't buy long air blow guns. I just remove the tip and put in a fitting w/a piece of copper tubing on it. I have one w/a piece of 1/4" tubing about 8-9 inches long that I can leave straight or bend into whatever shape is needed to get into or around corners, need to replace that tube every few years due to it being bent too many times. Also have a fitting w/a 3/8" tube about 3' long for the hard to reach places or just wanna stay away from the dust that's going to be kicked up.
I also have the drain on the tank relocated w/a ball valve for quick easy draining, drain it lots except in the winter when the water in the bottom of the tank is frozen. Did that once and boogered up the valve.

[jax55]

I piped mine to also use a ball valve instead of the "Radiator drain vavle" that came on it.
Piece of hose to route the condensation outside, and change the oil yearly.
I do all this after losing one to a seized pump and lack of maintenance.
This one has lasted many years and is still going strong.
I tried a couple of the HB auto drain deals, but kept blowing the hoses on it apart.

[Tom Wesenberg]

Yep, about 5 years ago I bought a H/F auto drain, and the hose blew apart the first time it cycled. My friend had a horizontal air compressor tank explode. He said it blew about 30 feet into the air. The bottom was rusty and split from end to end.

I usually lower the pressure switch shut off pressure to about 80 lbs. I don't usually need more than that, and it's easier on the pump and motor.

[mshmodela]

Yeah, water in a metal tank plus air plus time plus high pressure and well at some point you have a bomb.

[wmws]

Is there any way you can tell how much rust may be in the tank. I don't drain mine as often as I should. When the water comes out it does look rusty but no big particles.

[Marvin/TN]

The top blow gun most likely has an orifice in it to limit the PSI at the nozzle. Remove the long pipe, look in the body of the blow gun and you will see a brass orifice. you can either unscrew it or drill a bigger (1/8) hole in it. OHSA required the PSI limitation many years ago, about 40 years ago. I just drilled a bigger hole in it now have all the air I need. The bottom blow gun is probably the same bit I have never seen one like it. My blow gun had a short pipe. I drilled out the opening in it as well and soldered up the 4 holes opening side ways. They were to keep someone from getting hurt by pressing the end of the nozzle against the skin. I work by my self so no horse play with the air hose.

[holdover]

I have two 60 gal Husky compressors plumbed so I can use one or both at the same time. Works great when using air tools. The first thing I did when I purchased them was to plumb a drain with a ball valves to easily drain the tanks of H2O. I do a lot of painting so I drain the tanks at least twice a week and every time before I paint, even though I have water filters on the distribution point and at the spray gun. Takes lesss than a minute to drain both tanks

[Tom Wesenberg]

Originally Posted by wmws

Is there any way you can tell how much rust may be in the tank. I don't drain mine as often as I should. When the water comes out it does look rusty but no big particles.

This free air compressor I just got has the heavy duty tank with large threaded plugs in each end, so it would be easy to unscrew them to look inside. I got an air compressor for $15 about 15 years ago because the bottom of the tank had a small leak. I cut a piece out about 1" by 4" and that was the only rust spot in the tank. I welded a 1/4" plate with a drain plug over the hole I cut, and it's working fine.

The top blow gun from Fleet Farm is an excellent blow gun, but the just one from H/F blew so little air that I thought the holes were plugged with metal shavings, or not correctly drilled. I took it apart and nothing was wrong. It's just a poor design.

Here's a picture of how I ran my drain valve yesterday. I went to Menards and bought a 1/4" street el, a 6" pipe, and a ball valve. At first I ran it to the end of the tank, but this was no good because it would hit the ground when I lift the handle to roll the compressor, so I turned it to exit near the back of the wheel, where it's well protected and easy to drain.