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CL BLOG Continued from page 49 be expensive and lengthy. Knowledge without application experience leads to another type of long and costly learning curve. Both fnally lead to the realization that it is less expensive to hire the person who has both the knowledge and experience to avoid the occasions that lead one to gain that experience. After all, what is experience but the making of mistakes and learning that you will never do again what caused that mistake in the frst place? ing and fushing out the equipment, but There are a multitude of other benefts, it usually has a fushing arm. You need especially cost/waste savings and conto make sure you don't have any epoxy tainer disposal. mixing with the PUR. You can spray inorganic zincs We use both systems, as there is with plural systems by using one no one tool in this business that side (or both, for that matter) of solves all problems. Remember, the pump by pre-mixing the zinc a plural-component system can powder with the binder and applying it spray single-component paints. For short as a single-component paint. I would pot life coatings (1 h or less), you can't change out the static mixer with a straight Continued on page 53 beat the plural-component systems. A A Plural-component airless pump systems We are planning to use plural-component airless pump systems for our wind tower coating system to reduce material and labor costs. Our coating sys- Q tem consists of the following: • Zinc-rich epoxy (56% solids by volume) • Polyamide epoxy micaceous iron oxide (55% solids by volume) • Acrylic polyurethane (PUR) (55% solids by volume) Have you ever used this equipment for spraying these types of coatings? A We have used plural-feed airless and air-assisted pump systems to spray thin flm epoxies, with volume solids of 50 to 60%, both waterborne and solvent-free. They work well, eliminating waste and the need for hand mixing. You don't need heat for these types of products. You can get the equipment with fxed or variable mixing. You need to make sure that the mix ratio is set correctly and does not go off ratio. Purchase a unit with an alarm that informs the operator if the mix is off ratio. We have always used this process with a product being used in bulk, so always have the same mixing ratio. Once the short-mixed product line has been fushed out, we leave the unmixed components in the machine. If you are putting on a three-coat system, I don't know how easy it will be to keep cleanNACE International, Vol. 52, No. 5 May 2013 MATERIALS PERFORMANCE 51