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50% Quartz is better than white plaster.

 50% Quartz

50% Quartz is better than white plaster.

In one of the tests performed at the National Pool Industry Research Center, 50% Quartz finishes were evaluated to determine if they perform better than standard plaster. The testing was done to see at what ratio the quartz addition improved the performance of the finish, if at all.

The testing reported a 30% reduction in surface deterioration in quartz mixes of at least 50% when compared to standard plaster with no quartz additions. This means that less surface deterioration occurs in plaster finishes that have 50% of the aggregate weight as quartz. Quartz is inert and will not react with water chemistry. 50% Quartz will perform better than standard plaster.

Quartz finishes of at least 50% will improve the performance of your plaster investment as compared to standard plaster. You can chose from a variety of colors, however most choose blue quartz. The 50% quartz will not only improve the performance (as long as it is at least 50%) of that finish but will also give the water a hint of color.

The addition of quartz at a lesser concentration than 50% quartz will not offer any quality benefit. Just like adding dye to standard plaster, it will only add to the cost of the plaster investment. You need at least 50% quartz to improve the performance of the plaster finish.

In order to receive the best benefit of a quartz additive to your plaster investment a 100% quartz finish is the right decision. Though a 50% Quartz will improve your finish as compared to a standard plaster, a 100% quartz finish will be as good as any finish you could invest in for your pool.

It is ultimately up to you how long a plaster finish lasts in your pool. It cannot be over stated how important balanced water chemistry is relative to the long term success of your plaster finish

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White plaster is not a good finish.

Marble Dust acid test
White plaster is not good. It is too easily damaged by unbalanced pool water.

 

Marble Dust acid reaction
White plaster is not a good investment.

 

Standard white plaster is not a good finish to invest in for your pool replaster.

White plaster used to be the most common type of finish installed. This changed after testing showed the standard plaster was too easily damaged by out of balance water.  Standard plaster is a combination of white marble dust and white Portland cement. The marble dust registers less than a 3.0 on the Mohs Scale of Hardness. It is a very soft material. Portland cement registers around a 2.0 on the same scale. Standard plaster can be colored by adding pigment to achieve a desired color. It must be mentioned that doing this will result in an upgraded standard finish in expense, but you will not receive an upgrade in quality equal to the expense.  Standard plaster is the weakest plaster finish on the market.  It cannot stand up to water chemistry imbalances and generally will last 5 years with proper balanced water chemistry. Far less in unbalanced water chemistry.  How long a finish will last is a relative term. I refer to that as how long it will be enjoyable relative to how rough it has become or how easily it is stained.

Many homeowners and pool service companies will acid wash their white plaster pools in an attempt to remove stains.  This is the worst thing you can do to a standard plaster! When standard pool plaster is acid washed, the acid oxidizes the marble dust and the cement, effectively removing the outer finish coat of the plaster. Leaving behind the rough inner matrix of the finish. Initially stains are removed and the plaster is bright white.  But due to the roughness left behind stains return very quickly.  The finish becomes so rough you will no longer enjoy the pool.

Marble dust aggregate, used in standard plaster, placed in a glass beaker will oxidize completely to a liquid when combined with acid in a very short time, about 30 seconds. The acid is used to simulate aggressive water. When the same test is done with quartz and pebble, there is zero reaction at all.

My Hydro Demo Prep Process has allowed me to see how strong different types of plaster finishes are relative to how they respond to our 40,000 PSI test. I see consistent evidence from insight I have gained over the last 5 years water jetting pools on surfaces of all types, that white plaster should not be used in swimming pools.

If you want your pool plaster finish to last for a long time, do not use standard plaster. Choose a quartz finish or a pebble finish. Make sure it is installed by a National Plasterers Council member. Choosing one of those finishes and allowing someone who is not a NPC member to install it for you, will not provide you the results I expect you to receive, especially if they use a homebrew bond coat.  I will expand on the different quartz finishes options in my post next week.

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How to choose a good pool plaster finish

 

 oklahoma-flagstone-and-micro-fusion

Why are some pool plaster finishes more durable than others? A good plaster finish is one that is durable and also looks good. To be able to understand why some pool finishes are more durable than others, you must have some understanding of pool finish materials.

This post will primarily focus on the aggregate portion of the plaster mixes. The most common aggregates used in pool finishes are marble dust, quartz, and pebble.  It is the aggregate that is the variable and the major factor in every finish that helps determine if it is more durable or not.  Cement is more or less Calcium.

The Mohs Scale is used to measure the relative hardness of a mineral by its resistance to scratching. From softest to hardest, the ten minerals of the Mohs scale are talc (measuring 1 on the scale), gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and diamond (measuring 10 on the scale).  

Consider the difference between numbers in the Mohs Scale similar to the differences between and 2.0 and 6.0 earthquakes. The difference between the relative numbers on the Mohs scale are similar in distances apart as the earthquake numbers are different in relation to the damage that results from a 2.0 compared to a 6.0 earthquake.

Marble Dust registers at a number 3 on the Mohs Scale.  It is a very soft material. When a simple acid test (submerged in acid) is performed on marble dust, it completely oxidizes with nothing left.  When this same test is performed on both quartz and pebble, nothing happens. Quartz and pebble register at a number 7.0 on the Mohs Scale. The quartz and pebble are unaffected by the acid test.

The acid test is done to simulate aggressive pool water chemistry. If you have white plaster, it has marble dust in it as the aggregate. If your pool water is out of balance at any time the plaster will be damaged. White plaster is too weak to last for a long time even if the water chemistry is perfectly balanced.

Quartz and pebble finishes installed by National Plasterers Council members will outlast white plaster. White plaster should not be used in swimming pools.