The ABCs of PATs

by Rich Vurva

Powder-actuated tools (PATs) have been around since World War II, but today’s PATs are much faster and easier to operate than the earliest tools used to build and repair battle ships. To help you select the right solution for the types of jobs you do, here are PAT basics you need to know.

A powder-actuated tool uses a powder charge like the kind found in a firearm. PATs use energy from the charge to power a piston that drives a fastener into a concrete, masonry or steel surface.

“A PAT has a captive piston that is accelerated by the powder charge. This hits the head of the fastener just like a hammer would, which drives the fastener into the base material,” says Bill Georges, product manager for Simpson Strong-Tie.

Power loads for powder-actuated tools are essentially blank cartridges, color and number-coded for power level. Loads contain precise amounts of special powder to maintain consistent driving performance. They’re commonly available in single shot for .22 caliber tools and 10-shot strips for .27 caliber semi-automatic or automatic tools.

The manufacturer’s operator manual or application chart lists the appropriate color and level powder load, and generally, the harder the base material, the more powder needed.

It’s an industry standard that the higher the number, the greater the power. Always use the lowest-power charge when firing for the first time into previously untried material.

If you are unsure about the base material you are fastening into, perform a simple center punch test. Using a fastener as a punch, hammer it into the base material. If the fastener point becomes blunted, the material is too hard. If the material cracks or shatters, it means the material is too brittle. If the fastener sinks into the material with an average hammer blow, it’s too soft.

“It’s important that workers use the right load and power setting for the job,” says Mike Popovich, PAT engineer at ITW Ramset. “In untested material, start testing with a green. or lowest power load, and work up until you get adequate fastening. If you start with the red, or highest power load, you could shoot the pin all the way through the base material or cause concrete spalling.” Starting with the highest-power load also puts extra stress on the tool and the user. Starting with the lowest power load causes less stress all-around.

Tool types
Most PATs fall into one of these basic categories:

Single-shot, hammer-driven tools. These PATs are the simplest in design. The user inserts the load and the pin, then aligns the fastener on the work surface and hits the top of the tool with a hammer. This fires the load and drives the pin into the substrate.

Single-shot trigger tools. Single-shot tools are self-contained units actuated by pulling a trigger. They are still relatively simple in design but do not reduce the steps needed to load and fire a fastener.

Semi-automatic tools. Although users still have to place the pin in the tool before firing, the load feeds into the tool via a 10-load disc or strip as the user cocks or resets the tool. The semi-automatic load advance feature makes these tools more complicated, which increases maintenance needs.

Automatic tools. These tools can drive fasteners in a rapid-fire sequence. They allow the worker to quickly move along a work surface, fastening it to the substrate.

More than nails
Fasteners used in powder-actuated tools are not common nails. They are manufactured from special alloy steel using a specific heat-treating process to produce the right mix of hardness, toughness and ductility for PAT applications. All pins and loads must meet specifications set by the American National Standards Institute.

Some manufacturers have added corrosion-resistant pins for use with the new ACQ pressure treated lumber (see related story on page 42) and are marking them distinctly so users can tell them apart. For example, Craig Taylor, marketing director of DESA and Remington tools, says Remington marks its corrosion-resistant fasteners with a yellow oval.

Questions to ask
One of the first questions a supervisor should ask is whether the worker is qualified to operate these powerful tools.

“Anyone using a powder-actuated tool must carry a valid certification card specific to the tool being operated. The card verifies the user has been thoroughly trained and tested on how to use a specific PAT and the safety issues associated with PATs,” says Taylor.

Another key question to ask is how you intend to use the tool. That will determine the type of tool they should use.

“If a contractor is laying down a drywall track, for example, he’s looking for speed. He’s going to use an automatic tool with a 10-strip magazine that fires 10 shots repeatedly. If he’s just a general contractor, he doesn’t need speed but he needs a tool capable of shooting 3" pins with washers,” says Len Colasuonno, Powers Fasteners’ vice president of sales.

Is the tool intended for daily or occasional use? For everyday use, tools should be durable and easy to maintain. Concrete particles, dust and other debris can dramatically affect tool performance and life, so daily cleaning is recommended.

“Everybody is looking to solve the challenge of increasing speed on the jobsite but still maintaining reliability,” says Georges. He says the design of Simpson Strong-Tie’s new PTP-27AL makes it easy to clean and repair.

“Unscrew the cover, open the front of the tool and unscrew the noise piece and everything comes out for cleaning or to replace worn parts in the field,” he says.

Will the tool be used in a variety of applications? If so, versatility is an important consideration. Powers’ new PA 351 power-adjustable, fully automatic .27 caliber PAT includes an adjustable dial so users can quickly change power settings.

“If a contractor puts in a red load and finds out that’s too strong, he can turn the dial and make it a green or a yellow by closing the barrel of the tool,” Colasuonno says.

Will the tool be fired indoors? If so, tool noise may be a consideration. Simpson Strong-Tie’s newest tools feature a built-in muffler system that greatly reduces noise level.

“With the muffler system, especially if you’re not shooting a full power load, it’s very quiet. You would not even know it’s a powder-actuated tool,” says Georges.

Powder-actuated tools can take a hard job and make it easier. The right powder-actuated tool with the proper load and pin combination can help you drive home fasteners with speed, accuracy and efficiency.

Use tips
Although users must be trained and certified in PAT operation, Popovich recommends users refine their technique to get the best and safest fastening from these tools.

“Use two hands on the tool to fully compress the barrel perpendicular to the work surface. Hold the tool firmly as it fires,” he says.

Overhead applications may be more difficult, especially in areas  with hard aggregate. “Using the PAT on a pole or getting into position on a lift can help you make these shots more easily. However, in hard aggregate, you may see a success rate of only seven in 10. In these cases, try Ramset PowerPoint pins. Their bullet-shaped tip helps them penetrate harder concrete,” he says.

This appeared in the November/December 2004 issue of Contractor Tools and Supplies magazine.

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