Technical Engineering types, I have a question about air cfm

Can you plumb your compressor to a storage tank, then work off it?

 

I looked into a second tank, but most real aux tanks are extremely expensive. I have looked on FB Marketplace for an old compressor with a bad motor. A bigger line would be easier.

 

Just for giggles, I priced copper tonight. $38 for a 10' stick! Man, it's gone up.

 

you have to remember the tank size really doesn’t matter that much. It gives you stored energy but the compressor has to be able to keep up with demand.

 

So, if it acts as stored energy, would the larger piping act the same?

 

Larger pipe = less restriction.
Less restriction = higher flow with less pressure drop through the pipe.
Larger tank or larger pipe does have more storage capacity but it cannot make up for a compressor that's too small for the quantity of air needed at a given pressure. Part of the purpose of a larger tank is to keep the compressor from cycling on and off and on and off and....... A larger tank can also serve a high demand for air for a short time but eventually the "storage" is gone and you'd be operating at the CFM the compressor could put out at a particular pressure where the system would eventually "even out". My old compressor was way too small for a blast cabinet. It would only maintain about 40 PSI if used continuously. My larger compressor will maintain ~90 PSI at the compressor tank outlet (hose connection) which is enough for my blaster to work satisfactorily. The "piping" is a regular 3/8"(?) 25' long air hose.

I've seen the recommendation that a good pressure piping system would make a loop around the perimeter of the area it serves. That gives two directions that air can flow to any given point where air is used in the loop.

Lynn

 

My goal is to try and maximize the efficiency so my compressor and the blast cabinet work at their peak. I think the CFM will not really be an issue. Just tuning it up a tad.

 

I understand that.
I dump my 25 gallon into 60 gallon tank when use my cabinet. It gives me about ten minutes or so before the little compressor kicks back on. Let’s me take a break, pull the part out and look it over, etc. then I chill till it fills the big tank back up and the compressor shuts off. Rinse and repeat. Maybe I’m too patient, but I really don’t want to be staring into a cabinet for an hour straight

 

Oh shit, here he comes again...

Anyways, were you having any issues with the smaller cabinet, as in waiting for pressure, volume, etc? I peeked at what you're considering. I'm going to assume this is so you can do bigger parts, not have 2 blasting ops in the same cabinet. If that's the case then plug in the big one and have at it. Optimum doesn't always mean needed. Volume, pressure, CFM, all ratings to analyze. What are YOU doing? If it's the same in a bigger cabinet and you always did just fine...?

For the science faithful in the audience I too would tee off ¾ and send it leaving the ½ "behind" the source feed. You need a ¾ tee at the compressor to hook the flex gig to undisturbed and make your home run to the cabinet source. Maybe I'm being Capt Obvious...?

 

I think that’s what I will do. I am going to add a 3/4” Tee right after the flex line. Run a dedicated line to the cabinet. This should eliminate any issues.

As far as my present blast cabinet, it works ok. It was a used one I picked up off of CL years ago. It’s pretty small. I need more room for bigger parts.

 

The difference is mine isn’t the Limited edition, white lightning series. I just got the old regular series cabinet. All the cool kids get the cool stuff…

 

My brother used an old water heater tank out of his house. Worked great.

.

 

I thought about it, but the corrosion and the max pressure kinda worried me. With that kind of volume and it decided to let go, it could do some major damage.

On that vein, a friend used a 1000 gallon propane tank and buried it in the back yard behind the shop. He said the worst part was getting rid of the oil residue left over from the propane. He doesn't paint though, so he wasn't worried about fisheye.

 

My entire shop backbone is made of 3/4" lines. The pressure wash, and bead/sand blast cabinets are the 3rd and 4th thing after the compressors (we run two). Both are 40" from the compressors, on the other side of a sound deadened wall.

Both compressors have timed drains at the bottom, that release any water that has collected, opening for 1-second, every 15-minutes.

The first thing after the compressors is a 1-1/4" self-draining water trap, oil trap, and regulator (we run 120psi in the backbone, and local regulators for each tool area). The two compressors are tee'd together before it.

The second thing after the compressors is a refrigerated dryer. We only run the secondary when the primary is down, or being serviced, or am going-to-town with the DA while the CNC is running a tool change heavy job.

Both cabinets are plumed without QD's, with lines that exceed the diameter of they have onboard.

 

Since the supply lines are effectively part of the tank , they are part of the storage .
The only pertinent sizes are the blaster valve & orifice .

 

Gotta go with Tman on this: maybe what you have will work just fine. There are way too many variables to search for an analytical answer.

If you are not pleased with the performance of your easiest set-up, start making changes, beginning with the cheapest and easiest.