Air Compressors - which one should I buy?

[eyhonda]

No, they are rated at specific psi. Usually, the SCFM rating is given at more than one pressure. Example: My portable oilless compressor is rated:
6.9 SCFM @ 40 psi
5.5 SCFM @ 90 psi

My big compressor is rated at 36 SCFM @ 100 psi. (It's maximum pressure.)

OK, thanks for the clarification. So, it drops off with pressure. Wow, your big compressor IS big! I think our compressor here at work is similar. It's huge and impressive! IR, rotary screw, 15hp, 50scfm, 150 psi, 120 gal. Turns on for maybe 10 seconds at a time. Fast fill and quiet (under 70 dba)!! Not for home use!

 

[AlphaDogChoppers]

The only thing I can suggest is to look at the blast cabinet you want, and see what its CFM requirement is.

For instance, this cabinet consumes 9.5 CFM at 90 psi:
http://www.harborfreight.com/40-lb-capacity-floor-blast-cabinet-93608.html

Whereas this portable blaster which might be good for soda blasting consumes 2 CFM at 50 psi.
http://www.harborfreight.com/portable-abrasive-blaster-kit-37025.html

Which blasting method would be more effective? The one that uses more air, of course.

 

[AlphaDogChoppers]

Wow, your big compressor IS big!

Yes, it is. I wish it was actually mine. It belongs to the building I am in. Unfortunately, I am moving out this month, and I am going to have to buy at least a 5 hp compressor at first opportunity.

 

[eyhonda]

That's ok! Shopping for tools is almost as fun as shopping for motorcycle parts! Now you're in the same boat as the op!

 

[AlphaDogChoppers]

Yes, that's what makes this discussion so useful for ME. I never gave compressor capacity much thought until now, because I have had full-time access to a kick ass compressor for free.

The largest blast cabinet is also part of the building. I am going to have to replace that for around $1,200, so I have to find $2,000 just to replace that capability.

 

[crazypj]

What sort of SCFM should one look for to do efficient soda blasting?

SCFM just meand standard cubic feet (per) minute air delivery.
For blasting, bigger is better, maority of people (me included) use what we have which is too small for continuos blasting
Check this site, he gives some recommendations in there somewhere ;D
http://www.sandblasterinfo.com/

 

[eyhonda]

I never gave compressor capacity much thought until now, because I have had full-time access to a kick ass compressor for free.

Yeah, you were spoiled! I use our compressor too but off hours. It's an awesome setup. Those rotary compressors!!...

Kind of a topic tangent..

Is the blast cabinet a syphon type or pressurized type? Another idea for blasting I got from the local blaster, is to just have a dedicated room and use a pressurized blaster system. It's more powerful than a syphon type and a room will allow bigger parts. Also, you can get down and dirty on the part rather than thru a couple of port holes in a box. Lighting the part will be easier as well in a room. Just blast away with a full suit and mask, sweep up the blast material, sift it for foreign material and reuse it. I had a pressurized blaster once and I made up a temporary booth with plastic tarp. It was so powerful, the blast material made sparks off my frame!

What sort of SCFM should one look for to do efficient soda blasting?

What the others said. Go more than what the requirements are for your hungriest tool.

 

[Tim]

Well my puny little XS cases are at this shop for soda blasting. I think they fit in the cabinet ok.

 

[Tim]

Yeah that small HF cabinet calls for: Requires a 5 HP compressor with minimum 12 CFM at 40-80 PSI

Something like this HF 5HP 60 Gallon unit would more than fit the bill

http://www.harborfreight.com/air-tools/air-compressors/5-hp-60-gallon-165-psi-two-stage-air-compressor-93274.html

Air delivery: 13.5 CFM @ 165 PSI, 15.8 CFM @ 90 PSI, 16.4 CFM @ 40 PSI

Going to keep my eyes peeled on the ol' Craigslist. I've got one of those portable contractor units at the moment to run my air nailer to do trim work and hardwood installs at the house (thankfully I'm just about done, but the compressor has served me very well for 15+ years in two homes. 3000 sq ft of hardwood and the associated trim so far).

Wouldn't mind something more 'permanent' and useful for soda blasting.

 

[AlphaDogChoppers]

Is the blast cabinet a syphon type or pressurized type? Another idea for blasting I got from the local blaster, is to just have a dedicated room and use a pressurized blaster system. It's more powerful than a syphon type and a room will allow bigger parts. Also, you can get down and dirty on the part rather than thru a couple of port holes in a box. Lighting the part will be easier as well in a room. Just blast away with a full suit and mask, sweep up the blast material, sift it for foreign material and reuse it. I had a pressurized blaster once and I made up a temporary booth with plastic tarp. It was so powerful, the blast material made sparks off my frame!

My largest blast cabinet is siphon type with dust collection and media recovery. I have a smaller HF cabinet that is big enough for things like fork sliders. I have it loaded with glass bead. Also siphon type and I use my shop vac for dust collection.

I have a pressure pot portable blaster that holds 40 lbs of media. I have tried the dedicated room type. The bodily exposure and unpleasantness of being "in there" with the blast media majorly sucks. I will send stuff out for blasting before I do that again. Containing the mess was a major challenge. Really sucked. I would rather get a great big cabinet than ever go back into a room to blast. It was horrible.

I have a beard. Anything other than a pressure supplied mask, I end up getting waaay too much crap in my lungs.

 

[AlphaDogChoppers]

Something like this HF 5HP 60 Gallon unit would more than fit the bill

http://www.harborfreight.com/air-tools/air-compressors/5-hp-60-gallon-165-psi-two-stage-air-compressor-93274.html

Air delivery: 13.5 CFM @ 165 PSI, 15.8 CFM @ 90 PSI, 16.4 CFM @ 40 PSI

It's entirely possible that I may end up with that very compressor in my new shop. Gonna be a few months down the road, though.

When I am ready to buy, I will spend at least a couple months looking for used on craigslist.

 

[Tim]

Found this on our local Kijiji - but a little big and at 26cfm overkill. It's a monster! $900.

http://toronto.kijiji.ca/c-cars-vehicles-auto-parts-tires-other-parts-accessories-7-5-hp-compressor-W0QQAdIdZ352575952

 

[eyhonda]

Does anyone have any FHE with HF air compressors? If I had $800 to spend on a compressor, I wouldn't be shopping at HF. I go there for cheap tools. Just my opinion. I'd rather buy a good used brand name compressor for that kind of money. CL will have give you all sorts of treasure if you're fast on phone. An $800 used compressor might be $1200 new and still have lots of life left.

I just found one a few seconds ago....

http://detroit.craigslist.org/mcb/tls/2803709859.html

>>>Porter Cable Jetsream upright air compressor 175psi 7hp 80gal. tank in very good condition. only a couple years old must sell moving and cannot take with me. paid 1400.00 will sell for 800.00 or best offer.
>>>

Here's an IR. It's the 5hp version of the one I have (3hp), but I only paid $300.
http://detroit.craigslist.org/wyn/tls/2829738851.html

 

[bbqb4racin]

Found this on our local Kijiji - but a little big and at 26cfm overkill. It's a monster! $900.

http://toronto.kijiji.ca/c-cars-vehicles-auto-parts-tires-other-parts-accessories-7-5-hp-compressor-W0QQAdIdZ352575952

Looks perfect to me!