Selected Answers

From Charles Williams of kurbtblast on October 8, 2012:
     Difference are with capac ...read more      Difference are with capacity (gpm) and number of passes for adequate millage.

From Giuseppe Santagata of NACE Certif. Coat. Insp. level III # 2737 on October 9, 2012:
 Plural component requires  very expensi ...read more  Plural component requires  very expensive equipment, but it is fast with good production, and saves a lot of paint material, etc. This equipment needs a professional operator, especially to be sure to  obtain the correct mix ratio at the tip. Airless is 100% fast with very high production, but in some circumstances you have also 80% of paint loss if not set properly (pressure tip size and angle) and you need professional sprayers. The air spray or conventional spray is slow, produces a lot of dry/overspray, but has the possibility to work better in some difficul areas, as well as the possibility to clean the surface to be coated immediately before spraying by using the air in the gun.

From Jerry Trevino of Protective Liner Systems on October 21, 2012:
     Plural component pumps ar ...read more      Plural component pumps are very effective in spraying and applying 100% solid materials and are more productive than (hot potting) airless pumps. Conventional air spaying will not pump high solids, thick coatings. In the case of 50% to 60% solid materials, airless (hot potting) may be more efficient. Conventional spraying may be more efficient in applying thin, one to three mils of a top coat for uv protection or for an aesthetic coat over thicker coats of paint on the structural steel. All three types of spraying have their pro's and con's. Plural component spray systems have a high risk of being off ratio. Temperature adjustments may have to be made to attempt to equalize the viscosity of both components. In some cases, for instance, you must heat one of the two components more than the other. Fast-setting materials may only be sprayed with plural systems. The size of the project, location, overspray considerations, target paint thickness, and type of coating used are factors that have to be considered in selecting the type of spraying to be used.

From Jay Barstow of Aeroflor Consulting Services on October 16, 2012:
     Definitely, single-compon ...read more      Definitely, single-component airless hot potting a low-viscosity, solventless resin for DFT/sec/SF application. It's a function of viscosity and heat. I have shot over 3 GPM from single King airless for hours at a time on large flooring projects. Heat, especially in plural component, affects viscosity and flow, but because of internal mixing,  the effective pressure, and thus flow rate, is lost.

From Daniel Liu of APC on February 6, 2013:
    Plural component equipment is v ...read more     Plural component equipment is very expensive, but easy for operation during  coating application once the mixing ratio is set. Especially for those materials that include more than two parts, it can be faster and safer.
      Airless spray equipment is the most common equipment used on site. For  materials with high volume solids and higher total thickness sprayed on large areas, airless spray will be required, as it is faster and more convenient. Since the liquid is pressured without air, there is less chance of air entrapment in the coating film, which is very common in the shipbuilding coating field.
     Air spray is normally  used in the field where the thickness is mainly less than 100 microns. The coating material is atomized with pressured air, then blown out together with air to the substrate.  The air pressure is not strong enough to convey high solids materials, so air spray is normally used with very low solids and  low viscosity coatings.