How to use powder actuated tools

The DX E72 is Hilti’s most versatile single load, 0.22 caliber powder-actuated fastening tool, and is capable of handling pins ranging from ½ to 2⅞ inches for concrete and steel.

You probably know these tools even if the name is strange to you. Basically they’re used to drive specially hardened pins into concrete or steel using the explosive force of a special cartridge. Because they’re frequently used in framing, they’re also called stud guns or stud drivers.

Powder  actuated tools require hardened, sharpened specialty pins and anchors that can be driven into concrete or through steel. They’re never used with common nails or fasteners.

For a small job, a hand-held powder actuated tool that is fired with a hammer blow is adequate. It’s loaded with the pin and the charge is placed in position and then fired with a heavy hammer-blow. The tool is affordable but the process is slow.

For more extensive jobs, you can get a tool that does indeed look like a gun. It will use an individually loaded pin but with a strip or a circular magazine of the charges which are sized and look like .22 blanks. Again, you don’t use .22s but the special powder charges made for the tool.

Built to accomodate pins ranging from ½ to 2⅞ inches, the Hilti DX 36 0.27-Caliber Semi-Automatic Powder Actuated Tool features semi-automatic cartridge advance and piston return. The “boosters” load in strips of 10 that advance automatically when the tool is cycled.

High and low velocity

There are two types of powder actuated tools. A high-velocity model has no piston in the chamber so the propellant fires directly against the fastener, much like a handgun. High-velocity tools are not currently sold in the United States but there are still some around and they are extremely dangerous. Low-velocity models have a piston in the chamber, and though they produce less force, they drive pins just as well.

Powder actuated tools have safety mechanisms to prevent them from firing until they are pressed against the work.  Nevertheless, accidental firings do happen.  The best way to avoid them is to make sure the tool is never loaded until you’re ready to use it. In addition:

• Never push the muzzle back with your hand, whether it’s loaded or not
• Never put any part of your body where a pin could “nail” you
• Whenever you’re clambering around the jobsite, pull the cartridge magazine and be sure there are no pins in the barrel.

Hilti’s DX E72 powder actuated tool uses these 0.22 caliber yellow “boosters.”

Purchase cartridges and drive pins to match the tool and the job. Powder actuated tools can be used to attach framing to concrete floors, concrete and block walls, and concrete ceilings. Usually you’ll be looking at shooting the pins with enough power (and there are different power cartridges) to get 1 inch of penetration without burying the pin in the frame. Test fire to be sure you have the right pin and cartridge. Other fasteners that can be used with powder-actuated tools are threaded anchors, or pipe and electrical clips.

For good anchoring in concrete an inch of penetration is required. Since the most common task is attaching 2x4s to concrete slab, these pins are 2½ inches long. For anchoring 2x framing to steel beams, the pin needs to drive all the way through the steel and project at least a ⅛ inch through the steel. In the case of concrete, the material compresses around the pin, to hold it in place. Fired into steel, the steel pinches the pin and forms a step.

OSHA guidelines for use of powder actuated tools

Powder actuated tools operate like a loaded gun and should be treated with the same respect and safety precautions:

• Never use a powder actuated tool in an explosive or flammable atmosphere.
• Before using the tool, inspect it to determine that it is clean, all moving parts operate freely, and the barrel is free from obstructions.
• Never point it at anyone.
• Do no load the tool unless it is to be used immediately.
• Kept your hands clear of the barrel end.
• Always wear suitable eye and face protection.

To prevent the tool from firing accidentally, two separate motions are required for firing: first, bring the tool into position, and second, pull the trigger. Powder actuated tools must not be able to operate until they’re pressed against the work surface with a force that is 5 pounds greater than the weight of the tool.

If a powder-actuated tool misfires, wait at least 30 seconds before trying to fire it again. If it still will not fire, wait another 30 seconds so the faulty cartridge is less likely to explode, than carefully remove the load. Put the bad cartridge in water.

The muzzle end of the tool must have a protective shield or guard centered perpendicularly on the barrel to confine any flying fragments or particles. All powder actuated tools must be designed to work with varying powder charges so the user can select the powder level necessary to do the work without excessive force.

Only trained and certified employees should operate power actuated tools.

—By Steve Sturgess