Air compressors

Jim Burr said:

One way to eliminate the rust issue is to coat the tank with a ceramic coating product. Commonly used on gas tanks for classic car restoration. Since the air outlet is on the top of the compressor...no worries about clogging.

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Good luck with rolling the tank around to slosh the coating all over it for good coverage. I assume you'd need to leave the tank sit - unused - with all its orifices open so the coating can dry before pressurizing.

Actually, with regular draining, an uncoated tank should last for decades.

Ambient conditions, of course, will affect tank life. High humidity, and coastal 'salt air' will enhance corrosion. In the high desert, a tank oughtta last nearly forever.

I have said this before and had a lot of naysayers. I find volume to be a good substitute for hp. i had a CH for 20 years with an 8 gallon tank and a 4 hp motor(more like a 1hp) that did everything I needed for 30 years. I quit using it because of the tank. The real limit was the 8 gallon tank. I now have a Lowes unit with a 30 gallon tank that works fine and it is a smaller motor as well. The tank fills while I do other things I can't use any tool 100 percent. I bought a small high volume Hitachi between the units and quickly realized that tank volume was more important on my higher CFM tools. You are not going to be in production with your plasma cutter... So you cut 3 feet and wait 5 minutes big deal..

basically a 3 cfm unit will let you work 50 percent duty factor with a 6 cfm tool. Not precise but thats the way I look at air usage..

Garry brings up a good point. Which brand/ model is the plasma cutter and what is the duty cycle on it?

Garry Foster said:

I have said this before and had a lot of naysayers. I find volume to be a good substitute for hp. i had a CH for 20 years with an 8 gallon tank and a 4 hp motor(more like a 1hp) that did everything I needed for 30 years. I quit using it because of the tank. The real limit was the 8 gallon tank. I now have a Lowes unit with a 30 gallon tank that works fine and it is a smaller motor as well. The tank fills while I do other things I can't use any tool 100 percent. I bought a small high volume Hitachi between the units and quickly realized that tank volume was more important on my higher CFM tools. You are not going to be in production with your plasma cutter... So you cut 3 feet and wait 5 minutes big deal..

basically a 3 cfm unit will let you work 50 percent duty factor with a 6 cfm tool. Not precise but that's the way I look at air usage..

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Gary makes the point i have been wanting to articulate for years. Ever since i got it right to spray with a pancake compressor. Sure i cannot spray with a big high cfm gun or spray a car but i can spray small stuff easily.

When my pancake gave up for a while I got real lucky one day a Lowes and they had a one day special on a brand that they have called Blue Hawk. Well picked up one for $178 and it is a large tank think 20 gallons not sure. Just used that for spraying Xmas gifts and it was true delight. Never even came on as the pancake would. Proved the point to me about the tank and air volume availability issue.

My primary reason for getting an industrial strength compressor is so I can use a pneumatic sander on bowls and hollow forms. There are times when I'm sanding continuously for 30 to 60 minutes at a whack, and I got tired of hearing my little buzz bomb compressor running the entire time. With a pump that puts out 19+ cfm, my compressor can now get ahead of the 8 cfm sander and sit quietly about half the time. (It's also a LOT quieter when it's running compared to my old one.) I'm the first to admit that it's overkill for a hobbyist shop, but then again so is my Powermatic lathe.

Jim DeLaney said:

Good luck with rolling the tank around to slosh the coating all over it for good coverage. I assume you'd need to leave the tank sit - unused - with all its orifices open so the coating can dry before pressurizing.

Actually, with regular draining, an uncoated tank should last for decades.

Ambient conditions, of course, will affect tank life. High humidity, and coastal 'salt air' will enhance corrosion. In the high desert, a tank oughtta last nearly forever.

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Did it with 20-27 gallon tanks and no issuse...sorry, it was just a thought

With regard to the plasma cutter's air requirements and duty cycles. The short answer is, it depends. Anywhere from 50% to 100% duty cycle, depending on the thickness being cut. It has a flow meter and the indicator must reside in the middle position. There is a test mode setting to check that. I have a line on a couple of 20 gallon units, but I agree about the tank volume being essential. Those units are horizontal and used (who knows how much and whether any drainage ever occurred). I am leaning toward a vertical machine, probably new. A friend got one from HF to use with his lathe, same as Vaughn. His first one leaked like crazy and never could get it right. Would up getting another that works just fine. So that is an option. I am thinking 30 gallon minimum on the tank unless I get lucky with a bigger one. Thanks for the input and things to consider.

I just looked at the HF site. 29 (5.9 cfm at 90 psi) and 60 (15.8 cfm at 90 psi) gallon compressors are both on sale. Flow rates are given in the specs. Hope you find what you need at price you can afford.

Wayne

Another way to get a higher capasity air compressor.


Several years ago while talking to two different licensed plumbers I posed the question about making a air-compressor from a hot water tank. Both of them said that should be no problem at all because a HW tank was tested to well above the pressures I would need in a woodworking shop. That & the fact that my Dad had made one from a 30 gallon HW tank & used it for 25-30 years with no problems convinced me that I could safely go ahead with the project.

In talking with a friend of mine I mentioned the project. He said I have a horizontal 20 gallon tank with compressor head & motor with busted guages & no plug on the cord that was given to me that you can have if you'll bring the tank back to me when your through. Well that was a no brainer.

I took the AC home & wire nutted a long wire pigtail I had onto the power cord & wheeled the AC outside & pushed the door to & plugged the AC in & waited for the boom but it pumped up & shut off pressure unknown. Well at least the pressure switch worked.

I took it apart & put my project together & have had a 50 gallon AC for about 8-10 years now for the cost of a bit of welding rod & some paint & a nice ball valve to drain it. I do wear ear muffs when I open the valve. My tank doesn't rust it is glass lined. It runs all my staple & nail guns fine at almost no cost. I will some day buy a HVLP gun. I plan on building a wall hung cooler & moisture trap system of copper pipe which will add to the capasity .

If I need something to help keep up I'll just purchase one of the compressor heads available at HF.

http://www.harborfreight.com/3-hp-145-psi-cast-iron-twin-cylinder-air-compressor-pump-60638.html