I purchased a Makita Mac5200 air compressor primarily for a pin nailer and finish nailer but also for the occasional framer or small impact wrench. I am aware that the tank is too small and I plan on adding a second tank at so point.

My question is how much air loss should you expect from a tank over time? I am noticing that after about 8 hours with the machine unplugged it is going from 135 PSI to 125PSI. Eight hours more and it is 80PSI and additional 8 hours it is at 45PSI. With an additional 8 hours it is at 25PSI. Is this normal? Does it take a while for all the parts to seal?

Thanks guys.

Hey, Ed; It's probably better to shut the compressor off, and drain the tank when you're not using it.
135psi is pretty high. Doesn't your pin nailer recommend a lower pressure, maybe around 70psi ?

I'm w/ Dan...
as for the leak...
make up a soap solution of water and dish-soap and paint the joints...
kid's bubble solution works really well...

what brand of pinner are you using???
why do you feel the tank is too small??? cycle time frequency???
what are your settings on the outlet regulator???
what are your settings on the limit switch

as far as air loss goes...
I prefer EOD drain down as a better way to go...

and a 135 psi is a lot...

Thanks Guys. Sorry I did not make my self clear. I am not using it with a pin nailer or any nail gun at 135PSI. 135PSI is the unregulated side. I am aware that you should drain the tank after use. I just did this as a test to determine if there was any air leakage. The Makita only has a 5 gallon tank which is fine for nail guns--but for an impact wrench it is on the small side. I figured I would add a 11 gallon or larger tank if I use it with an impact wrench. It is a cheap compressor $299 at CPO and is really impressive; rated to 140PSI and 6.5CFM @90 and 6.9 @40PSI. Sound-wise it is loud rated at 90 decibels, but when I tested it in a closed garage it was 77-80 right next to the machine.

Thank you both for your concern--I appreciate that. I know people have been criticizing this forum as of late but I think it is awesome.

Thanks Stick for the advice about kid's bubble solution. I am using Hitachi NP35A @80PSI.

Back to my question--is it normal to have that much of an air lose over a 24 hour period. I have heard stories of compressors keeping pressure for a long time--or am I expecting too much? I guess the question is--do I have an air leak that I should chase down?

Thanks guys.

is that air loss w/ the air line connected???
chase down the air leak...

impact wrench on that small of compressor..
if the air consumption of the impact is near or more than the rating of the compressor the compressor will never keep up no matter how much additional tankage you add...
you have to stop using the wrench for a time to let the compressor charge the tanks...

I don't worry about air leaks that small. If I unplug my tools from mine it will stay up for days. With a tool connected maybe overnight before it's down to a few psi. And it depends on which tool. Some leak more than others. It takes quite a bit of air to run a 1/2" impact. I have a twin cylinder compressor with a big Baldor 3hp 220volt motor driving it and it won't keep up to heavy use. If you want heavy use out of an impact you'd probably be better to go electric.

I have a Husky 33 gallon vertical air compressor I use on pneumatic tools when wrenching on vehicles. I sometimes work late and turn off the compressor but don't release the air from the tank until the next day and it holds the pressure from when I left it, even with the hose still connected (but no tools). There is a leak somewhere on your system and could be the "M" fittings themselves or the drain valve.

This is what Makita claim,

"POWER : 6.5 CFM @ 90PSI; Powerful enough to run two framing nailers"

The loss of pressure indicates a leak, do you turn off the tap each day or leave the hose pressurized?

it seems that most air hose quick couplers leak to some degree, common. so if you are leaving an air hose connected, that would be my bet. if not, track down the leak on the unit as mentioned. if it is the hose, you can place a ball shut off valve before the hose connection to prevent leak down.