Better to run compressor non stop or start and stop?

[signcrafter]

I have a 30 gallon compressor that says it does 10.5 CFM @175 PSI. I've been doing a lot of sanding using a DA and a roloc disc on die grinder and have been working it pretty hard. If I continue to work the compressor will run non stop and stay at about 90 PSI. Is it better to keep working and let the compressor keep running? Or is it better to stop working when compressor starts up and let it catch up and keep doing this. I only get about a minute of work if that before it kicks back on.

Another question, if the compressor says 10.5 @ 175 PSI how many CFM is it at 90? I'm running the hose right from the compressor as of now, would it be better to hook up a regulator and dial the PSI down to 90? Would that give me more run time?

 

[larry_g]

Can't answer the question without knowing the duty cycle of the compressor. Better compressors will have a 100% duty cycle and cheaper ones will have a 25% duty cycle. For having a regulator, yes it would be advisable.

lg
no neat sig line

 

[Jas29]

What brand of compressor is it? also it would be recommended to lower the pressure to the amount the tool needs and yes it would give you a longer run time

 

[HMCFab9]

A regulator should help, but it sounds like you just have a way too small compressor.
Continuously running is not a good thing, but it doesn't sound like you have much of a choice.

 

[signcrafter]

It's a rolair compressor. It's the 30 gallon model in the link, the first one if you scroll down, http://www.rolair.net/products/spec_pages/electric_stationary/V3160K24.html#specs.

 

[Davefr]

I have a 30 gallon compressor that says it does 10.5 CFM @175 PSI. I've been doing a lot of sanding using a DA.

A DA is a huge air hog and they typically run long duty cycles. For example this little guy consumes a whopping 20 CFM:

For sanding I'd switch to electric. Your ears and compressor will be happier and they're just as effective IMHO.

 

[signcrafter]

I usually don't use the compressor this hard for this long. I had some older hammer heads that were in rough shape and got bored so decided to try and clean them up a little for fun. Also probably not using the right rolocs and the lowest grit sand paper I had was 100. So lots of effort to get some of the nicks out.

 

[signcrafter]

I put a regulator on and ran it at 90PSI and don't think there was much of a difference in time running before the compressor kicked back in.

 

[larry_g]

I did a bit of searching around the Rolair site and could find no specs on duty cycle. I would suggest that since that is a splash lubricated rod on that pump that you give it a bit of cooling time every 10 minutes.

lg
no neat sig line

 

[kams1973]

The duty cycle for the motor and pump aren't always the same. However, the motor data plate should have the duty cycle on it. If not, a simple phone call to rol-air should yield results.

 

[jsaw]

I have a 3 up 20 gallon compressor that I have had for 25 years.in my younger days I abused that poor thing something awful. I was doing body work running a sander. That compressor would run for 3 or 4 hours a night without shutting off. The tank would be so hot that you would burn your hand if you touched it. When it was 10 or 12 years old I replaced the crankcase gasket. You could still see the cross hatching in the cylinders.

 

[signcrafter]

I did a bit of searching around the Rolair site and could find no specs on duty cycle. I would suggest that since that is a splash lubricated rod on that pump that you give it a bit of cooling time every 10 minutes.

lg
no neat sig line

Is splash lubricated rods a bad thing? I don't know a lot about compressors and how they are oiled.

 

[CNGsaves]

If you're working it that hard, be sure to CHANGE OIL often.

 

[LandR]

Or get an additional tank plumbed in

 

[signcrafter]

If you're working it that hard, be sure to CHANGE OIL often.

How often is often? I don't work it this hard often at all. Mostly just some air nailers and impact and ratchet. Maybe turn it on once a week or so 95% of the time. But getting into doing a little body work here and there. I think part of the problem is I only had one roloc pad and it was pretty well used so it was taking a lot longer to do then it should have.

Or get an additional tank plumbed in

I have been looking into this option, trying to find an additional 60 gallon to plumb in so I can use the 30 gallon most of the time and when I want to do body work turn a couple of valves and use both tanks.

But adding a tank would just mean a little extra run time before taking a LOT longer to refill right?

 

[larry_g]

I only referred to splash lubricated as being something in the lower end compressors. A high end compressor will have pressure lube to the rod bearing. Splash lube is fine and most small compressors wikk have it just like your lower end mowers. I would not expect a splash lubed compressor to have a 100% duty cycle.

As to adding an extra tank to the system it will do you no good. The extra tank will allow a bit longer run time till the first compressor kick in and from that point on will do nothing to allow you to get more work done. If your already unable to fill a 30 gallon tank while running the sander then you will not be able to fill a larger tank. If you are doing the work till the pressure is to low and then wait till the tank fills routine then tank size will also get no more work done at the end of the day. Grabbing some random run numbers, say your working for 3 minutes and have to wait 3 minutes for the tank to fill now. Adding a 60 gallon tank will triple your air storage capacity. Now you can run 9 minutes and wait 9 minutes for the tanks to recharge. At the end of the day you still have only worked the tool 1/2 the time.

lg
no neat sig line

 

[signcrafter]

That's what I figured about the extra tank. I guess I'll just have to take more breaks. It's hard because I'm the type that once I start something I want to keep going! But this compressor is way more then I need most of the time. Also I think my worn out roloc disc was taking 10 times longer to complete the task then if I would have had a new one. So maybe it would have been just fine.