If your pool is already painted, you will need to know the existing paint type before applying any new paint as not all paints are compatible. This can be determined by sending a sample to Ramuc (or other paint manufacturer) if the paint type is unknown. There are also a few tests you can try. Take a 1 inch paint chip, immerse it in denatured alcohol. If the chip dissolves, it is a water-based acrylic. If it doesn't dissolve, immerse a new chip in 75% mineral spirits and 25% Xylol, wait 30 seconds and rub the chip between your thumb and forefinger. If it dissolves, the paint is a synthetic rubber-base coating. If not, try immersing one last chip in 100% Xylol. If it dissolves, the paint type is chlorinated rubber; if it does not, it is an epoxy.
There are three main types of pool paint currently used - epoxy, premium acrylic, and water-based acrylic. Chlorinated rubber paints were once very popular but have been largely phased out due to environmental concerns. We'll go over the pros and cons of each of three pool paints most commonly used today.
Epoxy pool paint, which is solvent-based, is the longest lasting and most resistant to chemicals, stains and abrasion. It has a life expectancy of up to 8 years and dries to a durable satin finish. Epoxy can be used on previously unpainted concrete, plaster, fiberglass, and gunite pools. It can also be used on pools previously coated with epoxy paint. Because it builds up to 8 mils dry per coat, epoxy can help smooth rough surfaces.
Application of epoxy paint is the most complicated of the three pool paint types. In addition to cleaning and acid-washing, bare fiberglass or previously painted epoxy surfaces must be sanded to a #80 grit profile. For all surfaces, a condensation test must be performed and paint cannot be applied until no condensation is present. Epoxy paint comes in a two gallon kit; each gallon must be individually mixed and then intermixed. The drying time for epoxy is the longest of the paint types, 5 - 7 dry days for outdoor pools and 10 - 14 days for indoor pools with proper ventilation. Epoxy will "chalk" over time; this is a breakdown of the top surface due to exposure to UV light and pool chemicals.
Premium acrylic pool paint is designed to comply with environmental regulations regarding VOCs (volatile organic compounds) and replace chlorinated and synthetic rubber-based paints. Acrylic can be used on unpainted concrete and plaster pools. It will also work on pools previously painted with acrylic, chlorinated rubber or synthetic rubber. It can be applied to a damp surface and dries to a high gloss finish. The drying (or cure) time for acrylic pool paint is 5 dry days for outdoor pools and 7 days for indoor pools with proper ventilation.
Acrylic paint should not be used on fiberglass or wood surfaces, or on hot tubs and spas. It is less chemical resistant than epoxy paint and can also chalk over time. Premium acrylic has a life expectancy of up to 4 years.
Water-based acrylic pool paint, also referred to as "Type DS" by the manufacturer Ramuc, offers the quickest drying time of the three paint types. Drying times for water-based acrylic are 3 dry days for outdoor pools and 6 days for indoor. This makes it the preferred choice when a pool needs to be refilled as soon as possible. However it has the shortest lifespan, rated at one season for commercial pools and up to 2 years for residential.
Water-based acrylic can be used on unpainted concrete and plaster pools, and pools that were previously painted with synthetic rubber, epoxy or acrylic. It should not be used on gunite or fiberglass surfaces or on hot tubs and spas. It dries to an eggshell finish. Type DS paint has the weakest chemical and stain resistance of the three paint types.
To summarize paint and surface compatibility, if you have an unpainted concrete or plaster pool, epoxy or premium acrylic are the best paint choices. For an unpainted fiberglass or gunite pool, epoxy is recommended. For pools previously painted with synthetic rubber or acrylic paint, your best options are premium acrylic or water-based acrylic. If the surface was painted with chlorinated rubber, premium acrylic would be recommended. Epoxy should be used if the pool was previously painted with epoxy.