air compressor thoughts

[jay case]

I have a oilless 12 gal now. Its a bit low on capacity when I want to blow out the shop and is the most noisy machine in my shop.

Looking at getting a used vertical 50 gal, 220v, 5hp 120psi or in that ballpark. Oil type. I could go over the top and get a double piston 175 psi and that longer between charges. Looks like somewhere between 300-500 for the 120psi models.

Any experience on what mfrs or other characteristics to look for and look out for?
thanks for any tips

[David Kreuzberg]

Jay-

It depends on what you want to do with the air. If you're just using it for blowing out the shop or spraying finish, or the occasional tire rotation with an impact wrench, then the 50 gal., 125 PSI should be just fine. If you plan to use pneumatic tools which gulp tremendous amounts of air, like sanders, then the two-stage is the compressor of choice, as it can supply air constantly at higher volumes and pressures.

The important numbers are expressed as SCFM (standard cubic feet per minute). They'll be listed somewhere on the unit, usually as XX CFM @ 90 PSI and XX CFM @ 40 PSI. These numbers mean that the compressor can produce a constant supply of air at those CFM's and pressures. Your air tools will have CFM requirements on their labels; just make sure that your compressor can keep up with the tool.

If you plan to spray oil-based paint, shellac, oil-based varnish or solvent-based lacquer, make sure you have a dryer to remove moisture before it gets to your spray gun (this is good practice for any air tool).

As far as manufacturers, I would avoid anything manufactured in China, which is more than likely what HF will have. Sears is questionable, but worth investigating. Check out Eaton or Campbell-Hausfeld (might be Chinese by now?) or Ingersoll-Rand. Try Craig's List. Farm supply stores usually have a good selection.

What you want is a compressor with a large enough tank for your needs, that includes a motor and piston(s) with enough oomph to fill the tank in a reasonable time and keep up with your tools. Look for a cast iron cylinder head.

Hope I've made sense, and let me know if you need more information.


kreuzie

[Harold Shay]

We just spent this saturday installing a 60 Gal DilVilsbiss. It was used and I knew the owner. I would be carful of a used compressor unless you get the chance to inspect the compressor. You will want to check for rust in the tank. There is always rust where there is mosture. Just make sure you buy with confidence. I would sugest Cast iron compressor and a 220 volt motor. Noticed HF has a 60 Gallon US General for 400 this week end. Almost all the good oil compressors are quiter than a oilless type.
Good hunting
Harold

[David Freed]

I bought a Campbell Hausfeld "Iron Force" 5 hp, 60 gallon compressor a few years ago and have used it quite a bit.

Several months ago I let the compressor run out of oil and it locked up, burned the belt off and filled the shop with smoke. I was outside making noise and didn't hear the screeching of the belt. I took it apart and found it was made with a steel crank, aluminum connecting rods, and no bearings. It used the splash method to lube everything. I heated the rod using a propane torch and was able to unseize it. I turned it by hand for several minutes, first spraying WD-40, then using 3 in 1 oil, then motor oil. It gradually got easier to turn and I finally put it all back together, lubing it with Lucas Hub Oil and filling the crankcase with it also. It has worked perfectly ever since.

I tell this story to show how well the compressor is working. It was my fault that it locked up. I was surprised that it was so easy to repair it using no parts. IIRC the company recommends using 30 wt oil, but I am sold on using the Lucas. When cold, it is almost like thin grease, but I heated it until it would run freely before I poured it in so it would flow into the rod "bearings". Now when I use the compressor for extended amounts of time and it gets extremely hot, the oil doesn't get as thin as water. When I shut the compressor off, the Lucas "sticks" and doesn't all runout into the crankcase.

[Chris Parks]

Pressure produced is largely dependant on the pressure valve/switch setting which either turns the motor or unloads the compressor head. It is not a specification which is fixed in stone so to speak. It can be set where you want it but then maybe cheap ones can't be but I have never used one of those. If you want more pressure just change the setting. Of course the compressor head itself won't compress past a certain point. The tank if in good condition will take a much higher pressure than any single stage compressor will subject it to.

[jay case]

Thanks. Thats all great advise.

What about a dryer? What would be appropriate for a home shop? With my 12 gal oilless when I paint, I remove moister from the tank and then I will put a desiccator in line with the HVLP gun to grab moisture.

How much is a dryer and where do you find those?

thanks for the tips?