Solution Summary: Wet Drywall Sanding Sponge
Dry sanding of drywall joint compound can result in high dust exposures that exceed the OSHA permissible exposure levels for total dust, and in some cases may exceed recommended exposure limits for crystalline silica. Sanding with a wet sanding sponge significantly reduces exposure.
Used slightly damp. Must be rinsed and wrung out as it becomes loaded with mud; approximately after each square yard of sanding. Depending on size and characteristics these may cost $2 to $6, but are generally more durable than sandpaper.
High dust exposures over a working lifetime can increase risk of chronic obstructive pulmonary disease (COPD) and crystalline silica (in some joint compounds) that is inhaled into the lungs can cause lung scarring and even increase the risk of lung cancer. Dry sanding of drywall joint compound can exceed the recommended exposure level for crystalline silica (0.05 mg/m3) and can be as much as 10 times the OSHA permissible exposure level for total dust (15 mg/m3).
How Risks are Reduced:
Water from the sponge and on the surface of the joint being sanded wets particles so that they adhere to the sponge or drop to the floor rather than remaining airborne. This is particularly effective for large particles, but there are still a lot of very small particles that are not easily visible which are small enough to inhale into the lung. Considerably less effective at reducing dust exposure than a vacuum dust collection system for drywall sanding, but an inexpensive alternative.
Although measurements were limited to a vertical work surface, there was significant exposure reduction measured compared to a hand sanding block without dust controls. Even though most visible dust is eliminated, some exposure to respirable dust remains. Young-Corbett measured 60% reduction in respirable dust compared to a dry hand sanding block. Vacuum dust collection systems were much more effective.
Effects on Productivity:
Using a wet sponge sander may have both positive and negative effects on productivity as opposed to dry hand sanding with a block and sandpaper. Positive because of reduced dust cleanup, negative because of the need to repeatedly rinse and wring out the sponge as it becomes loaded and less effective. Cleaning time may be minimized by having a bucket of clean water at your side, but this has to be replaced regularly with clean water. If you use too much water, there may be delays to allow for drying.
It is unclear whether there is an overall increase or decrease in productivity.
This requires access to water near the work station. It does not appear to be as effective at reduction of respirable dust as the vacuum local exhaust ventilation. Similar respirable dust exposure reduction effectiveness to using a pole sander on vertical/wall surfaces.
Another consideration would be the dermal effect of the water/joint compound mixture on the hands and forearms. Repeated, prolonged exposures to the solution may have adverse effects such as drying and cracking of the skin.
A possible solution to this problem would be a sanding sponge attached to a handle, much the same way as a spongemop. Most come equiped with a device to wring or squeeze excess water from the sponge. This handle may also eliminate the need for excessive bending and reaching.
3M Wet Sanding Sponges
A wet sanding sponge, such as this 3M Softback Sanding Sponge, is widely available in most hardware stores and predominantly used in the industry. http://www.3m.com or contact 1-888-364-3577