“Coverage” and HoldTight®102
HoldTight®102 is not a coating. It performs its two principal functions – salt removal and flash rust prevention — as an adjunct to and enhancement of pressure washing with water (and/or wet abrasive blasting, or “wet jet” blasting, or “water jetting”). Thus, the question “How much ‘102’ must I apply to a given area?” is irrelevant. The relevant, and indeed only meaningful question is, “How much water will I use when I blast and/or pressure wash a specific area, given the equipment I am using (specifically, water consumption in a given amount of time) and the “production rate” (specifically, how much surface area do I cover in a given amount of time)?” The answer to that question determines how much of the product will be required. In short: determine how much water you will use based on flow rate, production rate, and the surface area, then divide by the dilution ratio you have chosen: 50, 100, etc. (Different flow and production rates will apply, of course, when water is used as part of the stripping process in wet-abrasive blasting. In such cases 102 must be used both in the stripping or removal operation and in the wash down operation.)
With regard to washing down surfaces after dry or wet-abrasive abrasive blasting —
We know from experience that 102-treated water applied at flow rates of less than 1 gpm under less than 500 psi at the surface is not sufficient to remove all abrasive dust, shattered corrosion products, and tiny paint particles, even when the surface has been “blown” clean with air only. (In fact, “blowing” a surface clean of dust generated by the abrasive blasting operation may result in adding contaminants to the surface from the compressor.) When such contaminants remain on the surface, flash rusting will occur.
We also know from experience that the cleanest surfaces are achieved with 102-treated water over 500 p.s.i. at 2-3 g.p.m. In most cases 2 g.p.m. at 1,500 p.s.i., or higher, will achieve the best results. At these recommended flow rates and pressures operator productivity is simply not a critical factor. The water flow and pressure, NOT the “dwell time”, are the determining factors (the “controlling variables”) so long as the water is treated with 102. If the operator, in those cases, moves the wash wand or tip very quickly over the entire targeted surface, he will use less HoldTight®102 without jeopardizing surface cleanliness. If he moves slowly, he will use more HoldTight®102, but will achieve the same result. Based on experience reported to us by many customers, these operations typically “clean” 500 to 1,000 square feet per hour. (Production rate is of course a function of operator skill and strength, surface flatness vs. surface irregularities, and constraints imposed by positioning equipment, scaffolding, lifts, etc.)
If the water does not contain HoldTight®102 in the recommended ratio the surfaces will flash. If the water is significantly substandard (in terms of chlorides or other contaminants and/or carbonates [hardness]) as discussed in our literature on the subject, the surfaces might “flash” or “turn” even with 102 (or, for that matter, any additive that purports to remove contaminants). In such cases, either increasing the 102 to water ratio or pre-treating the water, or some combination of both, will be necessary.