Getting better performance out of air compressor

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Hello,I mainly want to use my air compressor for a die grinder I have with various attachments. The problem I have is that when I pull the trigger on the die grinder it has good power for about 1 second then slows way down (I have psi set to around 90-100, and a couple seconds after holding the trigger down the regulator then reads like 30psi). So basically its pretty much worthless at this point.I want to know how I can fix this so it has power, and I know that its not the biggest compressor but I expected a bit more out of it. Or if there is a way I could modify it to flow better? Could my regulator be the problem?Here are some stats on the compressor:3HP (4HP peak).8 gallonsCut in pressure is 90psiCut out pressure is 120psiAir outlet is 1/4nptAir flow ratings:4.5 SCFM @ 115psi5.6 SCFM @ 906.2 SCFM @ 707.25 SCFM @ 40Any help is greatly appreaciated, thanks!
Reply:Judging by your flow ratings, I'd say your compressor is undersized for a die grinder. Add another gauge to read actual tank pressure when reg is reading 30 psi. Maybe part of the problem is in the regulator.                                         MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw
Reply:I think you just need more flow, like one with at least 10-12 SCFM's at 100psi.  Someone else with more knowledge is sure to chime in.  In the mean time i think i saw a thread farther down that answered some of your questions here.Here is the link.http://weldingweb.com/vbb/showthread.php?t=33933Last edited by fordtrucks; 09-17-2009 at 02:47 PM.
Reply:Originally Posted by mla2ofusJudging by your flow ratings, I'd say your compressor is undersized for a die grinder. Add another gauge to read actual tank pressure when reg is reading 30 psi. Maybe part of the problem is in the regulator.                                         Mike
Reply:So your saying that the reg. says 30psi and the motor has not kicked in yet, because your tank still reads 90psi?  This really sounds like a reg. problem.When you let go of the trigger on the tool does the pressure rise rapidly again?
Reply:Yeah, here is what will happen... tank reads 100psi, reg reads 100psi. I pull trigger, red pressure drops down to 30psi gradually over like 2 seconds and stays there. Slowly the tank pressure drops, and when the tank pressure drops to like 80-90 then the motor kicks in to re-fill the tank. As soon as I let off the trigger, the reg pressure rapidly goes back up to match the tank pressure (takes a couple seconds for it to get back up)
Reply:you need to adjust your regulator while using the tool.  Sounds like your gauge is creeping up to tank pressure between uses.  Plug in a blow gun, pull the trigger, and adjust the reg while air is flowing.It's all kinda moot anyway cuz my 33 gal with 6.4 cfm @ 90 won't keep up with a die grinder.  Your little 8 gal doesn't have a chance.My name's not Jim....
Reply:There is a knob on the regulator to adjust, and its all the way down for the highest pressure setting
Reply:Try turning it the other way, if that doesn't work, get a new reg.My name's not Jim....
Reply:Die grinders, especially less expensive ones, can take a lot of air. Small regulators often can't flow a lot of air and maintain regulation.I would remove the reg. At 100PSI (90 cut in, 110 out on the pressure switch), you really don't need it. You can adjust the speed of the grinder using the adjusting screw on the grinder.It is also possible that there is something in the line between the regulator and the tank obstructing flow, or that the regulator is bad. I doubt that a unit this small has  a flow limiter, but you never know. (If the flow goes above a preset limit, it restricts the flow to a very low rate until the flow is stopped. They are used to protect workers from flailing lines if a hose separates or is cut and are required by OSHA when hoses are used to feed tools. If the unit has one, it is probably set to limit flow in the ballpark of the max sustainable delivery rate for the pump, which may be below the demand of the grinder)
Reply:Ok I will try removing the regulator and see how it performs thanks!
Reply:On this topic of air powered die grinders;  is it more efficient(better, easier, smarter, etc.) to use the air powered grinder, or a corded angle grinder?  I have a couple of electric angle grinders and use them a good bit, but maybe I am missing something by overlooking my compressor capabilities.  Sorry to intrude on the compressor performance thread....just thought I'd ask.Nctox,  Stickmate LX  235AC/160DC  HH210
Reply:Originally Posted by nctoxOn this topic of air powered die grinders;  is it more efficient(better, easier, smarter, etc.) to use the air powered grinder, or a corded angle grinder?  I have a couple of electric angle grinders and use them a good bit, but maybe I am missing something by overlooking my compressor capabilities.  Sorry to intrude on the compressor performance thread....just thought I'd ask.
Reply:Thanks....Nctox,  Stickmate LX  235AC/160DC  HH210
Reply:Ok so using some brass fittings, I made a "Y" spliter, one branch goes to the regulator like normal, the other branch goes to just a hook up, unregulated source. Sure enough I plug in to the unregulated source and it has all of the power in the world, works perfectly now. So the issue was either in the regulator, or one of the brass fittings leading up to the regulator had too small of a hole in it, restricting air flow. Thanks again for all the help!
Reply:Glad ya got it fixed. Either the regulator is junk or there is an obstruction in the high side reg inlet. I seldom need regulated air, so I put male and female quick connects on the reg and just plug it in the comp and hook the air hose to it.                        MikeOl' Stonebreaker  "Experience is the name everyone gives to their mistakes"Hobart G-213 portableMiller 175 migMiller thunderbolt ac/dc stick Victor O/A setupMakita chop saw