Need Assistance on Shop Air Supply

[pancholasvegas]

Good Afternoon All,

Reaching out for assistance from the collective -

I've gotten to the stage at my shop where I am in need of my own blast cabinet (Harbor Freight will be the choice). I've been able to get by in the past with using other people's, but I'm ready to get my own.

The issue is that my current compressor is a 24 Gallon, 1.5 Horse, I believe Porter Cable. This has served me well in the past with my LIMITED use of Air Tools, and has been enough for painting smaller parts, motorcycle tanks, etc, but it was definitely at the limits of what the compressor could do.

That being said, outside of the paint gun, I've rarely needed air for tools, but there are some air tools that I would definitely like to add to my setup.

The big question -

Would it be worthwhile to purchase a 2nd Compressor (24 Gallon or so, essentially the same as what I have now), and run these in-series to allow more air? OR do I finally need to step up to something larger, like a 50-60 gallon area?

If the recommendation is to utilize 2 compressors in series, what is the best path forward to do this? Ideally, I'd like to set this up as "Plug and Play," I.e.; I don't want to mess with anything other than turning the power on and hooking up the hose to the tool.

If I need to upgrade the compressor - Are there any recommendations for machinery that comes in under $1,000 or so? Might be asking a lot, but 110 is preferred, if possible. My panel is running low on room since pulling the 220 for the heater.

I believe that I need at least 9 CFM at 90 PSI available, according to the specifications on the blasting cabinet.

Thank you everyone in advance.

 

[GeoBruin]

There is no 120 volt compressor on the market that will make 9 CFM. The closest is about 7. To that end, your options are to upgrade a 240 volt compressor, or to add another compressor to run in parallel. Do you have multiple circuits available in your shop on which you can separate the two 120 compressors? If not, you're going to be bumping up against a single circuit's capacity.

In any case, in today's market, $1,000 doesn't go very far for a compressor. I would encourage you to look at the used market near you if there is one. Otherwise any of the 240 volt 5 horsepower options available from a big box store will probably be about the same. That includes anything with a Quincy badge or an Ingersoll Rand badge, both of which will be imported units in this price range.

I'll say this now before Denny has a chance to come in here and say it loudly and unapologetically: the bigger the better for blasting. That said, you can blast some with a less than optimal setup. I'm actually a big fan of putting two compressors in parallel but will leave it to others to discuss the nuances of doing so.

 

[pancholasvegas]

There is no 120 volt compressor on the market that will make 9 CFM. The closest is about 7. To that end, your options are to upgrade a 240 volt compressor, or to add another compressor to run in parallel. Do you have multiple circuits available in your shop on which you can separate the two 120 compressors? If not, you're going to be bumping up against a single circuit's capacity.

In any case, in today's market, $1,000 doesn't go very far for a compressor. I would encourage you to look at the used market near you if there is one. Otherwise any of the 240 volt 5 horsepower options available from a big box store will probably be about the same. That includes anything with a Quincy badge or an Ingersoll Rand badge, both of which will be imported units in this price range.

I'll say this now before Denny has a chance to come in here and say it loudly and unapologetically: the bigger the better for blasting. That said, you can blast some with a less than optimal setup. I'm actually a big fan of putting two compressors in parallel but will leave it to others to discuss the nuances of doing so.

Thank you for the information, especially in regards to 120V not being an option for what I am looking for.

To answer your questions & provide additional insight
- Yes, I do have the ability to have multiple circuits, that is a non-issue.
- Yes, I do have the availability in the panel to add another 240V outlet.

I'm definitely more interested in running these in parallel, mostly due to cost. I don't use air tools much, but the blasting cabinet & spray gun are the two big items. Hard to swing paying upwards of $1,000 when they aren't going to be regular use items.

Do you think that running in parallel will achieve what I am looking to do? If so, any recommendations on the best, easiest way to set that up?

 

[GeoBruin]

Thank you for the information, especially in regards to 120V not being an option for what I am looking for.

To answer your questions & provide additional insight
- Yes, I do have the ability to have multiple circuits, that is a non-issue.
- Yes, I do have the availability in the panel to add another 240V outlet.

I'm definitely more interested in running these in parallel, mostly due to cost. I don't use air tools much, but the blasting cabinet & spray gun are the two big items. Hard to swing paying upwards of $1,000 when they aren't going to be regular use items.

Do you think that running in parallel will achieve what I am looking to do? If so, any recommendations on the best, easiest way to set that up?

We would need some more specs for your existing compressor. Specifically, CFM at 90 psi (to figure out how much total air you will have with the addition of another compressor of given output). Also, it would be helpful to know the pressure your tank is rated for. Things are very very simple if the max pressure ratings for both compressors are similar. In that case you can literally just plumb the tanks together and Bob's your uncle. Of course, if the cut in pressures are too similar, you might set one a little higher or a little lower just to prevent both compressors from kicking on at the same time. Even if you're on separate circuits, you might be putting undue stress on the sub panel breaker.

If the two compressors have wildly different max pressures, you need to start looking at check valves to make sure you don't over fill one tank or the other. At some point, it might become easier to use a manifold. The other issue is a lot of smaller compressors don't have tank bungs. The only way to connect is after the pressure switch. So I guess that's the next question. Does your compressor have an available bung on the tank or not? Would the new compressor?

 

[Schurkey]

Glass-beading at more than ~90 psi just shatters the glass beads without producing a better result. I have a separate regulator on the glass-bead cabinet to keep the working pressure reasonable.

You don't need high-pressure, but you're going to need a heap of volume to keep up with the blast cabinet. It's not an impact wrench or air-ratchet that's used intermittently. A die-grinder or a bead-blaster uses a LOT of air. Two 120-volt machines is probably not going to cut it, although that somewhat depends on the air consumption of the blast cabinet you choose.

My set-up is a 5-horse, 80-gallon two-stage, and it never shuts off when I'm blasting, but the tank never drops to or below 90 psi, either. You don't need high pressure but the additional pressure means more air storage in the tank, which is nice. You can always regulate the pressure "down", but it's impossible to regulate it "up". A single-stage with a big tank could work for you (at least until you start buying more air tools, or the blast cabinet is bigger than I anticipate.)

Virtually everyone buys a too-small air compressor. I did that...twice. You've done that once. Don't make that mistake again.

 

[chris142]

I've ran stuff off a small compressor by using a large storage tank. Blast away then wait till it refills the tank and blast again .

 

[pancholasvegas]

Glass-beading at more than ~90 psi just shatters the glass beads without producing a better result. I have a separate regulator on the glass-bead cabinet to keep the working pressure reasonable.

You don't need high-pressure, but you're going to need a heap of volume to keep up with the blast cabinet. It's not an impact wrench or air-ratchet that's used intermittently. A die-grinder or a bead-blaster uses a LOT of air. Two 120-volt machines is probably not going to cut it, although that somewhat depends on the air consumption of the blast cabinet you choose.

My set-up is a 5-horse, 80-gallon two-stage, and it never shuts off when I'm blasting, but the tank never drops to or below 90 psi, either. You don't need high pressure but the additional pressure means more air storage in the tank, which is nice. You can always regulate the pressure "down", but it's impossible to regulate it "up". A single-stage with a big tank could work for you (at least until you start buying more air tools, or the blast cabinet is bigger than I anticipate.)

Virtually everyone buys a too-small air compressor. I did that...twice. You've done that once. Don't make that mistake again.

Alright. Consider me convinced. I’ve got the room and the power for a bigger machine. Sounds like I just need to wait a bit longer and build up the budget. thank you and everyone else for the insight.

 

[scooby074]

One thing that uses a ton of air is a sandblaster. Its essentially a wide open hole into your air tank that runs consistently.

I have a compressor that can deliver 18cfm, and IMHO its not enough for a blaster. I can get by, but its not ideal, plus, because it has to run continiously, it makes a lot of water which is death to a sandblasting system.

I have the Princess Auto version of the HF cabinet, and TBH its garbage. Ive been messing around with it for years. Sometimes I get it in the sweet spot and it works, but most time it doesnt and is more frustration than its worth. A lot comes down to the gun I think. There are kits out there to upgrade the gun, they look interesting but I havent tried them yet.

My advise is to avoid a blaster and look at other methods, unless you can get a big enough compressor (20cfm+) and perhaps a used, better quality cab.

 

[Citation]

Two in parallel can make sense if you already have the things. I've suggested it from time to time but it's almost never a better choice if you have power and space. I'm not sure if your current compressor is a belt drive 120V. I have something like that but I always find them hard to recommend. The issue being they cost almost as much as a 60 gallon "3hp" 240V compressor. If you can buy the 120V belt drive, just pay the extra $100 for the larger 60 gallon unit. Also, you can still tie in your existing compressor to the 60 gallon unit assuming they have similar pressure specs. My rule here is the blow off valves must either be the same pressure or the one with the higher pressure doesn't exceed the safely limits of either compressor. So it's OK if one compressor is 135psi max, and the other is 155 max so long as the tanks are rated for 175 and the blow off valves are rated for 165 (all example numbers). A "3hp" 240V compressor will likely deliver 10-12 cfm. Your old compressor might deliver another 5. That gives you 15-17 which is very usable.

I would suggest an after cooler with water trap between the pump and tank. It will help keep your air dryer.

 

[pancholasvegas]

Two in parallel can make sense if you already have the things. I've suggested it from time to time but it's almost never a better choice if you have power and space. I'm not sure if your current compressor is a belt drive 120V. I have something like that but I always find them hard to recommend. The issue being they cost almost as much as a 60 gallon "3hp" 240V compressor. If you can buy the 120V belt drive, just pay the extra $100 for the larger 60 gallon unit. Also, you can still tie in your existing compressor to the 60 gallon unit assuming they have similar pressure specs. My rule here is the blow off valves must either be the same pressure or the one with the higher pressure doesn't exceed the safely limits of either compressor. So it's OK if one compressor is 135psi max, and the other is 155 max so long as the tanks are rated for 175 and the blow off valves are rated for 165 (all example numbers). A "3hp" 240V compressor will likely deliver 10-12 cfm. Your old compressor might deliver another 5. That gives you 15-17 which is very usable.

I would suggest an after cooler with water trap between the pump and tank. It will help keep your air dryer.

I appreciate the insight. Definitely food for thought. It sounds like my best course of action is to just get the biggest compressor I can afford, so I’ll just have to save a bit more and wait a bit longer. Managed this far so a bit longer won’t kill me.

 

[pancholasvegas]

One thing that uses a ton of air is a sandblaster. Its essentially a wide open hole into your air tank that runs consistently.

I have a compressor that can deliver 18cfm, and IMHO its not enough for a blaster. I can get by, but its not ideal, plus, because it has to run continiously, it makes a lot of water which is death to a sandblasting system.

I have the Princess Auto version of the HF cabinet, and TBH its garbage. Ive been messing around with it for years. Sometimes I get it in the sweet spot and it works, but most time it doesnt and is more frustration than its worth. A lot comes down to the gun I think. There are kits out there to upgrade the gun, they look interesting but I havent tried them yet.

My advise is to avoid a blaster and look at other methods, unless you can get a big enough compressor (20cfm+) and perhaps a used, better quality cab.

I appreciate the insight. I’ve used the HF cabinets in the past and am familiar with their shortcomings and the required upgrades for a good user experience.

I’m at the stage with my projects & fabrication where a blaster is required. I’d like to note that I’m not blasting large pieces, but small bits (motorcycle parts) and I am not a production / job shop, so duty cycle and all that is fine. Thank you for the insight, however. And much to your point, if I can come across a better cabinet on the used market, I’d prefer that. I check marketplace regularly, that’s how I’ve outfitted most of the garage.

 

[u2slow]

The other issue is a lot of smaller compressors don't have tank bungs. The only way to connect is after the pressure switch. So I guess that's the next question. Does your compressor have an available bung on the tank or not? Would the new compressor?

Fwiw, I've worked around that. I hogged out the pressure switch bung (actually a large reducing bushing) to 1/2" NPT and added a tee before the pressure switch.

Not that its the overall solution for OP.