New compressor, help me not make the same mistake.

[nismomans13]

Well about 5-6 years ago i bought a 33 gallon oil less craftsman compressor. Long story short i hate it. Its loud and can't keep up with half my tools anymore. So i'm in the market for a new one. Here is the mistake i don't want to make again.

On my current model i have a good year 3/8 air hose, in order for me to get 90 psi to my tools i need to have the air line pressurized to around 110-115 psi. This is something i don't want to do any more. I've tried to understand the cfm and all that but it seems to just go over my head. I'm looking for a 240v or gas powered model, but what cfm ratings should i look for?

 

[stricht8]

The highest you can afford! If you are operating a spray gun or air sanders you will definitely want cfm in the teens/

 

[wineslob]

Well about 5-6 years ago i bought a 33 gallon oil less craftsman compressor. Long story short i hate it. Its loud and can't keep up with half my tools anymore. So i'm in the market for a new one. Here is the mistake i don't want to make again.

On my current model i have a good year 3/8 air hose, in order for me to get 90 psi to my tools i need to have the air line pressurized to around 110-115 psi. This is something i don't want to do any more. I've tried to understand the cfm and all that but it seems to just go over my head. I'm looking for a 240v or gas powered model, but what cfm ratings should i look for?[/QUOTE]

Like the poster above me, as much as you can afford. Use 3.5 CFM per HP(real) as a guide.

1 HP is 16 amps (ave) at 120 Volts, use the motor plate as a guide, not "peak" HP that will probably be on the tank in big, bold, decals.

 

[woody 73]

Good advise from Stricht8...
Go with the largest lines that you can plumb in,use a large air hose and find a larger tank size.

 

[lametec]

in order for me to get 90 psi to my tools i need to have the air line pressurized to around 110-115 psi.

What you need is a bigger and/or shorter hose.

Pressure drop in the hose has nothing to do with your compressor.

 

[usmc_noma]

what tools are you using?

 

[ATTappman]

I have that same compressor, and yes it has limitations, but it does OK with impact wrenches, air hammers, and ratchets. You might try using Milton HVLP couplers, especially replacing the stock one at the regulator outlet. You might try replacing the regulator with a better one with less droop, but I don't know how to find one of those because they don't list the pressure drop vs. inlet pressure and flow rate for any regulator sold online that I know of.

But if you need a higher flow rate for sanding, painting, or near-continuous ratcheting, you need a 60 or 80 gal tank and a bigger motor and pump that can produce 10 CFM or more. One thing to keep in mind is that once the motor power gets above about 2 HP, you could trip a 20 amp breaker on a 120 V circuit. So a bigger motor could require you to run a 240 V circuit to your garage.

 

[nismomans13]

what tools are you using?

when i bought it was for impact gun and inflating tires only, but as i get more and more into fab work i use more and more tools. I use most everything but a d/a sander. I used a hvlp gun the other day to prime my car and it actually did VERY well. But honestly the size is just not working for me, i use my impact on 3 lug nuts and its kicking on the compressor and boy is it LOUD. I'm looking at some older industrial models i'm seeing on craigslist, but i'm taking all the advice i see here.

 

[l_bilyk]

Aim for 240v 5 running hp. I think that's the most you can get on house current. Reservoir size doesn't matter much, but you will find most compressors with this size motor will have something around 60 or 80 gal

 

[Skin]

size matters a lot for an electric compressor, the point of the larger tank is to prevent the motor from having to run constantly and for long durations.

 

[tjmonsen5]

when i bought it was for impact gun and inflating tires only, but as i get more and more into fab work i use more and more tools. I use most everything but a d/a sander. I used a hvlp gun the other day to prime my car and it actually did VERY well. But honestly the size is just not working for me, i use my impact on 3 lug nuts and its kicking on the compressor and boy is it LOUD. I'm looking at some older industrial models i'm seeing on craigslist, but i'm taking all the advice i see here.

3 lug nuts and it turns on again? jeez

I fill my 25 gallon Craftsman professional up, and unplug it. I can remove all 16 of my lug nuts plus more on that tank. Im using an IR 231 impact gun.

 

[stricht8]

3 lug nuts and it turns on again? jeez

I fill my 25 gallon Craftsman professional up, and unplug it. I can remove all 16 of my lug nuts plus more on that tank. Im using an IR 231 impact gun.

Good to know since I have the same air compressor. I use it mostly for sheetmetal fab/ body work and it does well with die grinders, 2 inch angle grinders, air saws, cutoff tools air chisels and small 3 inch sanders. It fairs poorly with larger sanders. The quality of the air tool also plays a role as cheaper tools **** air. I had a cheaper but not so cheap Husky cut off tool and it required way too much air. I then tried an expensive MAC cut off tool and sure enough it works just fine.

 

[MattT]

You might try replacing the regulator with a better one with less droop, but I don't know how to find one of those because they don't list the pressure drop vs. inlet pressure and flow rate for any regulator sold online that I know of.

http://content.smcetech.com/pdf/ar.pdf has graphs for SMC regulators. You can probably find similar for other name brands.

To translate the graphs into English divide lpm by 28 to get CFM and 0.1 MPa is 1 bar or ~ 15psi.

 

[nismomans13]

I think i've decided on a Kobalt 60 gallon, 155 PSI max pressure, 13.4 SCFM @ 40 PSI, 11.5 SCFM @ 90 PSI , 3.7 running HP. Its better than what i have and is in my price range. I'm not looking to spend thousands on a compressor. I've already done that with my tool box, welders and countless other things. I just want to be able to run tools and not hear my deafening oil less kick on every 2 mins.

 

[Skin]

just a fair warning but that will be totally inadequate to run media blasting tools for any reasonable sustained period, either for paint removal or parts cleanup, if you ever go there.

too bad you put so much stock into other locations. I'd take a cheapo tool box and a great compressor any day of the week. Personally i wouldnt even consider units that dont do at east 15+ CFM @ 150/175PSI.

 

[Major Ramifications]

just a fair warning but that will be totally inadequate to run media blasting tools for any reasonable sustained period, either for paint removal or parts cleanup, if you ever go there.

If that's true, then my dad and I both have not done any blasting over the years, and I assure you that we both have done PLENTY. Yes, we could get more done in less time if we had an unlimited air supply, but this hasn't changed the results.
I AM an advocate of buying the biggest compressor you can afford, but I also know that you CAN blast with a unit like he is describing or even smaller.

 

[Skin]

If that's true, then my dad and I both have not done any blasting over the years, and I assure you that we both have done PLENTY. Yes, we could get more done in less time if we had an unlimited air supply, but this hasn't changed the results.
I AM an advocate of buying the biggest compressor you can afford, but I also know that you CAN blast with a unit like he is describing or even smaller.

yep, but it also depends on the size of the nozzle you're using but if you like listening to the tank recharge you can do it with many compressors.

 

[nismomans13]

just a fair warning but that will be totally inadequate to run media blasting tools for any reasonable sustained period, either for paint removal or parts cleanup, if you ever go there.

too bad you put so much stock into other locations. I'd take a cheapo tool box and a great compressor any day of the week. Personally i wouldnt even consider units that dont do at east 15+ CFM @ 150/175PSI.

i don't have a blast cabinet anyway. I did want one, but for the amount of parts I actually would need cleaned like that its really not worth it, a right angle die grinder with a sanding disc works perfect for me right now.

as for investing into other areas, i'm a pretty serious welder so i wanted a awesome machine, tool box just came out of necessity (its not snap on or anything) air compressor was always a tool that i just used to zip off lug nuts and fill up tires so i never took the time to really invest in one.