Compressor general info

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Old 07-04-07, 05:28 AM
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Unhappy Compressor general info

I have an 80 gal/5 hp Ingersoll Rand compressor,an upgrade from a 4 hp/60 gal Farm Hand unit. Most of the air tools and flex lines I see are 3/8" with 1/4" fittings. When trying to use(for example) a media/sand blaster, it will quickly use most of the air stored in it's pressure tank. The big compressor doesn't seem to replace the loss of pressure perhaps due to the 3/8" air line(?). Then it fills the blaster tank back up fairly slowly. So I can't get much production done this way.

I presently have 3/8" line from the tank to a regulator and then 3/8" line to the air tool, a sand blaster in this case. Everything has 1/4" fittings.

Is there a better way to plumb the air delivery system to deliver the quantity of air the compressor is rated at? This one is rated at something over 20 cfm at 90 psi. I would think this would be more than enough for most air tools.
 
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Old 07-04-07, 05:52 AM
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With that CFM you should definately upgrade to 1/2" hoses and 3/8" fittings, possible larger. You may have to go to an industrial supply house to get them.
 
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Old 07-04-07, 06:06 AM
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Sandblasting takes a lot of air [cfm] Long ago I worked for an outfit that also did sandblasting. If I remember right they had a 4 cyl gas motor to power the compressor - both the motor and tank was mounted on a trailer. I think the supply hose was 1.5"-2" diameter.

Now I know your not trying to blast commercially but this is a high air consumption job. Is the air compressor keeping up or is it running constantly?
 
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Old 07-05-07, 05:21 AM
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Question Air

Thanks guys.

Part of my problem is that most air tools for the DIY market seem to have 1/4" fittings at the tool. This is true even with the regulators and water traps. Do you think larger lines will help when there will still be 1/4" restrictions at the tool?

I am considering plumbing from the compressor to the job bay using essentially galvanized 1/2" or larger pipe with no filters, only a regulator or even use of individual pressure regulators on each tool.

Also, the previous compressor did not run continuously and would only come on after a couple of exhausting the pressure in the sand blaster tank. It seems to me that the pressure regulator at the compressor did not "read" the pressure lose untill it had to resupply the pressure in the flexible 3/8" lines.
 
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Old 07-05-07, 05:37 AM
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I've never used one of those pressurized sandblasting tanks. I do have a small sand hopper type unit that I was disappointed with because of the low volume and the amount of cfm needed. It's my understanding that the pressurized units are supposed to work better.

I don't know for sure but I'd expect there is a problem with either the compressor regulator or the regulator/valve on the sand blasting unit. Even with an open 1/4" fitting it should allow enough air loss for the compressor to engage quickly. IMO plumbing the compressor to the shop area with 1/2" pipe is always a good idea.
 
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Old 07-05-07, 07:29 AM
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bigger line

is always a good idea. But you have to evaluate your compressor vs the blaster too. What size nozzle are you using? 1/8 nozzle requires about 15 cfm, which should be fine for your size compressor and 3/8 hose. But if you go up to 3/16, you may be using up to 40 cf of air in a minute! That's too much for the 3/8 line and also too much for your machine and you'll get the inevitable pressure drop.
 
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Old 07-05-07, 11:48 AM
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Lightbulb

All good points.

I need to find out what regular old galvanized water pipe can take in the way of operating pressure, but assuming it is OK up to 175 psi, I am leaning torward a hard piped 3/4' system. I have found an industrial pressure regulator with 3/4" inlet/outlet for about $135 good up to 250 psi and 100 cfm. If I put that in the pipe line to control the presure, I won't have to deal with individual tool pressure regulators.

Once I get this done, I will use the shortest possible flex lines for my air tools, including the pressurized sand blaster.

Based on what you all have said, it further convinces me that the air compressor I took back had a faulty pressure regulator.
 
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Old 07-09-07, 03:30 AM
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Size of sandblast tank

What size is the sandblast pot? 10 or 20 Gal? what is sand pot rated for?if it's not indust. rated do waist your money on indust. reg. and blast hose and size gun tip? what type of media are you using? don't worry about lower part right now something for thought latter, answer info above will get us
closer to a fix.
I just thought of compressor rating there is alot of misleading info out there.
read info from Eaton air compressor on ebay, his older listing had some good info to test true hp and cfm. read a few listing there is alot of info all through there not to buy his stuff but the info is true on how missleading alot of brands rating are. I see it all the time now. including my compressors I recieved a 7.5 hp 80 gal as a gift. thanks baby! (she tried) but my old ugly 5 hp runs circles around it. don't tell her. 7.5 hp is a peak rating not true hp.
read his info and see if your 5 hp is really stronger than your old 4 hp. going by name brands you up granded no dought but alot of compressors are same maker differant paint jobs. I like your new air compressor and should be good for what you want but doesn't heart to see if rating are true. hp and cfm.

Why not put a tee on you compressor 1/4 on one side and bigger on other side. use quik dissconnects on sandblast pot so when not in use get it out of the way. your pipe would work also off a tee. I don't know how much room you have and how often you use sandblaster is why I said quik connect hoes But you need to keep moister out off sandblast tank however you plumb air hose. just a tank drain on you air compressor is fine for your 1/4 side of a tee but not on blast side, espeically if you are reloading pot a few times a job.
 
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