Acid Washing

Acid Washing


Posted By on Mar 28, 2014

An acid wash is, put simply, purposeful stripping of a tiny layer of plaster, exposing fresh plaster beneath. Therefore, it is ill-advised to make it an annual custom, which will accelerate the need for re-plastering. Most plaster coats (sometimes called whitecoat or marcite) are in excess of 1/2″, so a few careful acid washes should not hurt. You may also decide on an acid wash not because of swamp conditions, but just to bring out a brighter, whiter finish. Mineral stains and/or deposits, chlorine stains, even dirt stains…an acid wash is always a dramatic aesthetic improvement. If your pool has had years of algae blooms, and if your pool seems to grow algae overnight or just bloom very easily….changing the water and acid washing can help give you an algae free summer. Acid is a dangerous substance. Pool company personnel are specially trained in its application and wear protective clothing and breathing apparatus during the acid wash. To protect our environment, the acid/water waste should be neutralized with soda ash prior to its being pumped to a safe location. If you decide to drain and clean your own pool, make sure that the hydrostatic relief plugs are pulled as soon as possible, and that the water is pumped to a distant location, or into a storm drain. You may also need to check with local water authorities for waste water discharge regulations. As you drain the pool, wash it down (scrub if necessary) to remove all algae and leaves. Bag up all leaves and debris in the pool’s bottom. When the pool is clean and empty, you can begin to acid wash the plaster. Put on protective clothing and rubber boots, goggles and wear a breathing mask designed for acid fumes. Add 1 gallon acid to 1 gallon water (Always add acid to water, never the other way around). Wet down the wall with a hose. Keep the hose(s) running at all times, without a nozzle on it. Pour the acid/water mixture down the wall, from top to bottom, one 10 foot section at a time. Do not allow the acid to sit on the plaster for very long. Usually 30 seconds is long enough. Use an acid brush to scrub the surfaces and move the acid around. Rinse quickly and thoroughly. Make sure acid is rinsed completely, as it will continue to etch the plaster. Also try to prevent the acid from wearing a channel path from shallow end to deep end. This can create a worn stripe on the floor. If the 50/ 50 mixture isn’t strong enough, you can increase the acid strength or the hang...

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