I stained a red oak floor the color the homeowner wanted, but now they say it isn’t dark enough. Can I stain it again?
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On the Double
I stained a red oak floor the color the homeowner wanted, but now they say it isn’t dark enough. Can I stain it again?
Mike Sundell, vice president at Greenville, S.C.-based RM Designs, answers:
Most oil-based stains contain a very small amount of binder. They contain color pigments and dyes, and are designed to be wiped into the open grain to color the fiber and open grain of the wood. The wiped-on coat is thin enough for the topcoat or sealer to penetrate and bond to the wood fiber.
If a second coat of stain is applied, it builds the thickness, and the sealer or topcoat cannot penetrate through the stain to grab the wood fiber. Now you’re relying on the strength of the stain to bond the surface coats to the wood. Most stains do not have enough strength to hold the entire film surface together, so the finish peels.
If the stain was not dark enough, screen it off and start over with a darker color. If the color was right, just not intense enough, water-pop the grain after screening to increase the color load. A third method is to screen with a coarser grit, which will also increase the color loading in the grain. If the color just wasn’t right, you’ll need to sand it off completely and restain the floor.
Under Pressure
How do I know what drum pressure to use on my big machine?
Russ Watts, North American sander specialist for Palo Duro Hardwoods Inc. and Lägler, answers:
This has come to be one of my favorite questions, as it brings up one of the most overlooked aspects of floor sanding. The simple answer to this question goes something like this:
The proper drum pressure depends on the stage of the sanding process. The right pressure is influenced primarily by a three-way marriage of sandpaper grit, drum pressure and walking speed. In general, this marriage brings optimal sanding results by working in such a way that the lower the selected sandpaper grit is, the heavier the drum pressure selection should be, and the slower the operator’s walking speed should be. As the sandpaper grits move up during the sanding process, the drum pressure should be lessened, while the operator’s walking speed should increase. For example, a typical “cutting grit” of sandpaper belt is 36. In most instances, a 36 grit would call for a big machine’s heaviest drum pressure setting and a relatively slow walking speed. If the next sanding step calls for a 60-grit belt, you would use a mid-range drum pressure setting and your walking speed would increase. Finally, for a 100-grit belt, you would use the lightest drum pressure setting and your walking speed would increase yet again.
The effects of drum pressure on the quality of the completed sand job can be dramatic. In addition to practicing good sanding methods, we advise a big machine maintenance regimen that includes cleaning and lubing the suspension hinge points, along with weighing out and calibrating its drum pressure once every 12 to 18 months.
On the Loose
Why do my floors seem loose and have a lot of movement?
Glen Miller, manufacturer division manager at the NWFA, answers:
There are a number of possible reasons for this and it ranges from manufacturing to installation to conditions in the home. Without destructive testing, the determination of the exact cause may not be possible; it could be a combination of causes or one individual issue.
Let’s begin with manufacturing: Tongue and groove configuration may be a cause. There must be contact between the bottom of the tongue and upper part of the bottom groove. Without this, the chance for the floor to squeak or be loose increases. Even a properly attached floor with this condition may be loose.
Installation of the floor boards is also critical. Subfloor conditions, fastening schedule and the fastener air pressure are all factors. Always check to make sure the subfloor is properly fastened and within flatness tolerances. Fastening schedules vary depending on the flooring width; follow NWFA or manufacturer recommendations. Air pressure is also critical. The fastener should always be set properly. Do not over-drive the fastener, as this potentially fractures the tongues, possibly causing the loose floor boards. The proper air pressure adjustment is recommended by the fastener machine manufacturers. Under-fastening the flooring also creates the potential for the floor to move up and down.
Proper temperature and humidity controls are important. With variances in these two factors, the wood will shrink or expand accordingly and allow some movement.