Tandem Compressors

[imagineer]

I have to set up a quick & cheap media blast cabinet for a one time project. It does not warrant buying/building a real blast cabinet or buying/renting a larger compressor.

I am wondering about the risks involved in piping two compressors together to get the necessary volume.

I have two 5hp, 20 gallon compressors, each rated for 3.5 CFM @ 90 PSI. The blast nozzle I'll be using calls for 6 CFM @ 60-80 PSI. I'll be shooting medium sized glass bead.

Would it be dangerous to make up a T fitting and have both compressors feed into one line to the blast cabinet? I'll have the regulators on both compressors set to 45 PSI or so.

[Charlie C]

If I understand what you are wanting to do it would be ok. You would want to make sure that each compressor would shut off before one of the tanks got over pressure but than the relief valve should lift.

[cutter]

imagineer, this was discussed at some length in this thread recently although chevyoneton was considering a more permanent arrangement.

Still, you might find some useful insight there.

[Dr Dean]

I've done it with 3 plumbed together, then found out I still didn't have enough air so I started the semi tractor and tapped it into the system. All of my compressors are set to cut out between 120-125 psi. The semi tapped into the system made enough extra air that things could shut off and cool down. I know that a big diesel running just for the air compressor is a waste but its a case of use what you got.

[Ironman]

In the real world, with a 1200 and a 1600 cfm diesel compressor tied together, there are experts in the mining field you can call on to balance the controls so both machines kick in together. If not, one will overpower the other and blow the oil out of the screw compressor through the air intake.
In my experience this works fine for a while until moisture or whatever causes one to drift a few pounds. Then the fun starts all over.
The solution for me was to disable the contrls on one machine and slave it to the other. After that both stacks were pouring out smoke at the same time, and idling at the same time.

[imagineer]

Well it worked. I plumbed two small compressors together to make the air volume needed for media blasting. Other that it being insanely loud in the shop with two oil-less compressors running, it worked perfectly.

The project was to medial blast some aluminum car rims. I ended up building a cabinet from scrap aluminum sheet and a bit of extrusion.

Even though I was shooting light grain glass bead, the interior is lined with additional sacrificial aluminum panels just incase I would let the gun linger in one spot too long.

This whole effort was merely a practice run. Once I have my process and costs worked out, I'll invest in a real compressor and build a few larger steel cabinets for production work.

[rmack898]

That looks like a nice cabinet pieced together from scrap for just a practice run. I'd like to see the cabinets you build when you're ready to do the real job

[LW Hiway]

I have to set up a quick & cheap media blast cabinet for a one time project. It does not warrant buying/building a real blast cabinet or buying/renting a larger compressor.

Uh, good thing you kept to your original plans for a quick and cheap cabinet. Here I was thinking you'd use a couple wash tubs outside and a syphon tube for the media.

In any case, I do hope your using a respirator, and not just a paper dust mask.

Nice cabinet BTW.

For Al wheels I've used walnut shell over glass, and then dusted those parts with different media for different final needs in look.

LW

[SlimJim]

Originally Posted by rmack898

That looks like a nice cabinet pieced together from scrap for just a practice run. I'd like to see the cabinets you build when you're ready to do the real job

Mac. that's exactly what i was thinking!

Hey Imagineer, any chance you can design and throw together a practice run English wheel for me? I would love to see that, actually I would love to own and use it even more! Mike you need post more, judging on some of your past threads it looks like you have a lot to contribute.

Jim

[imagineer]

Originally Posted by LW Hiway

Uh, good thing you kept to your original plans for a quick and cheap cabinet. Here I was thinking you'd use a couple wash tubs outside and a syphon tube for the media.

In any case, I do hope your using a respirator, and not just a paper dust mask.

Nice cabinet BTW.

For Al wheels I've used walnut shell over glass, and then dusted those parts with different media for different final needs in look.

LW

Guilty...I only wore a paper mask. Next time around I'll wear a respirator.
This project stemmed from not being able to find a local media blaster that wanted to take on a small job like 4 car rims (or didn't want a fortune for doing so). So I made my own set up.

Since, for my own future projects, I will build a larger cabinet(s) and will need a larger compressor to feed it, I might as well make some $$ with them.

The new plan is to develop a side business, targeting small jobs, that I can take care of nights and weekends. I'm not even close yet and already have about $1000 in orders waiting.