I purchased a pneumatic nail gun called a “JakPack” last year to help put up molding. This thing is AWESOME. It is a standard nail gun, that attaches to a small CO2 tank that clips to my workbelt. Very handy.
The problem I’ve got is that I’ve never really worked with pneumatic tools before, and it tended to put divots in the wood where I was placing the nails. Is this a sign of to much air pressure? Holding it wrong? I had to go back through and fill the divots with wood putty. I’m hoping to avoid that this year, if possible.
My guess is that the CO2 tank has too much pressure for the gun. A normal nail gun is designed for 75-150 psi and your tank could be pressurized to as high as 500-800 psi. Make sure the regulator is adjusted to whatever the nail gun specifies.
However, it might not make that much difference in the end: I installed moulding for a living for a while, and we always had to putty the nail holes. Even if the gun leaves no divot, you have to putty or else the shine will be visible from the metal nail. (If there is no divot, you still gotta take a nail set to it and drive it down below the surface of the wood, so that you can cover it up with putty.)
If you’re concerned about it, you can invest in a headless pinner, but the pins aren’t nearly as strong as nails, and in many cases, you’ll need to putty to hide the metal anyway.
Randy nailed it (heh). Too much pressure. I’ve shot around 100,000 nails from a standard nailgun, 5,000 from a battery powered nailgun, and at least at least 500 from a Ramset. I can’t say I’ve ever shot one from a CO2 gun, but from taking a full, pressurized air tank to a job site, there is a definite change in divot depth when the tank starts to run out. I’m not familiar with the JetPack, but there’s got to be a way to turn the pressure down. Check the owners manual, it may be a screw near where the nails come out (the “head”, if you will).
I’m going to disagree with the “too much pressure” answer. Finishing nail guns are supposed to slightly countersink the fastener, with putty and paint or wax stick follow-up to make the hole invisible.
While most new finishing guns have a provision for adjusting depth of drive in the field, older and low end units lack this feature. My Senco finishing gun is ~ 15 years old, and although it is a workhorse, no adjustment exists. It consistently countersinks by about 1/16" to 1/8".
Getting back to the pneumatic power source, applying pressure above manufacturer listed maximum can damage the tool, and would be a significant safety concern. For this reason, pressure regulators are supplied to reduce compressor tank or bottle pressure to the desired device pressure. For years I’ve been using spare SCBA steel cylinders as an air source for nailers. When full, they are pressurized to ~ 2200 PSI (no typo), and can deliver enough power to drive ~ 350 16d framing nails before failing to set the fasteners flush. Part of that setup is a very good quality regulator, for safety’s sake, and to protect the tools.
Underpressurizing a pneumatic tool typically leads to protruding fasteners, incomplete cycling of the tool, misfeeds, and such.