How to Size Air Compressor?
 

In the market for a new one. Want to be able to run an impact, maybe a grinder/sander etc. How do I size the compressor? Currently I have a very small one that can't manage any of those things for long. The size of the 20-30g will work. Is that enough and how many HP motor?

Thanks

You will never regret overbuying an air compressor.

Don't be cheap here when it comes to buying a unit for running automotive tools or air sanders you need the highest cfm or scfm rating you can buy. Aside from the tank size you will also need some HP. Look at all specs. needed to run you tools and use that as a base line to start from.;)

Cubic feet per minute is as important if not more than how big the tank is; you can easily add a second tank to increase the air storage but a larger head is a bit harder.

cubic feet per minute is the important thing HP much less so
Personally I think IR products are worth buying

I bought a 60 gallon 220V upright Kobalt a few months ago for some light car restoration work. I use it every other weekend for some grinding, cutting, sprayed some primer, etc.. I think it's supposed to supply ~10cfm at 90psi. It cycles much more than I thought it would, but I am glad to have air tools. It seems adequate for what I am doing in my two car garage at home. If I had a real shop, or did more than an odd weekends worth cutting, grinding, etc., on cars I would sell it and buy something bigger.

I pretty much do what you need to do. Mine has an 80 gallon tank, runs up to 175 PSI at 18 CFM. 7 HP 220 volt electric motor. I regulate it down to 100 PSI at the lines and have a good filter/dryer on it. What gets you is a bead blasting cabinet or a small sand blasting unit that uses air constantly. A spray gun if you're painting an old tractor and really pouring the paint on is a big draw too. I don't consider this unit overkill either.

220v is a must, unless there is some weird limitation like 220v isn't available in your country or something odd like that. The guy I bought my compressor from had just upgraded his shop to 3-phase power :eek:

Calculate the biggest compressor you think you'd ever need, based on what you think you'll be using it for, then go two models larger.

Another way to do it is to find the biggest, baddest compressor you can afford, then get the next up.

No guy has ever said "I wish I'd bought a smaller compressor"

That thing is huge. 30 amp 220? Do you have some way to dry the air or just rely on long pipes?

10 to 16 CFM at 90 PSI sixty gallon is a good home use. You will be able to do some sand blasting (small parts) Prime and Painting if you are using an HVLP gun and any air tool you want to use. Less than 10 CFM is just a pain in the a__. I've had to use a small one for a while when the IR was broken again Just a pain in the A__.

Steve the other half of Angela

I would rather buy a good quality used one than a sub-par quality new. Search Craigslist or other local sites there are still a lot of people dumping tools to raise cash. I'm a fan of IR products they have been around a long time and are excellent quality. I was able to score a 60 gallon two stage IR a few years ago and it EASILY handles everything I throw at it. You'll never regret buying quality.

yep, 30 amp 220 with a magnetic starter. I have several of the dryer/filter units that the air goes through. Not real expensive but do a fairly good job.

oh yes, if you can find one of the old slow turning compressors you've got a deal. Those things seem to last forever. My is getting slow after 20 years of use. Time for an o/h kit.