Power-driven fasteners for plywood installations

can cause problems with fastener "pops," or squeaks when fastening floor sheathing or underlayment. Nonnally the operator; himself, can provide the force required to eliminate gaps beneath undedayment or floor sheathing by standing on the panel adjacent to where the fastener is being driven.

Since material densities vary, it's impossible to find an air pressure setting that will consistenfly drive the fasteners flush.

Galvanized fasteners should be protected with a chromate coating to increase their staining resiscance.

Additional cautions for those using power-driven fasteners:

1. Contact. Occasionally, the light weight high velocity fastening equipment doesn't provide sufficient force against the panel to ensure that the sheet is tight against the framing. This or fnore ,nlonnaton on power-drtven r considerations, contact the American Plywood Association, Technical Services Division. P.O. Box 11700, Tacoma, Wa 9M11; (2M) 56566m.

2. Thin Galvanizing. Power-driven fasteners must be smooth and unifonn in diameter to avoid jamming the nailer or stapler's feed mechanism. Conventional electro-galvanizing, which provides the required smoothness, is often too thin to provide longtemr corrosion resistance. When high corrosion resistance is needed, suggest fasteners of a material that does not corrode, such as aluminum or stainless steel.

3. Overdriving. The typical power nailer or stapler used today for building construction often countersinks the fastener. Adjusting the air pressure is an unpredictable method for controlling how deep the fastener is driven.

The solution to overdriving is to have the driver in the nailer or sCapler modified or ground off so that it can only drive the fasteners flush. Once this is done, it's only necessary to adjust the air pressure sufficiently high enough to drive the fas0ener in the densest materials. In material of lower density, they'll still be driven flush. Manufacturers of various pneumatic guns say they approve of grinding off the driver, but they strongly urge that one of their repaimren do this so that the driver is ground offproperly.