The polyester or polyurethane coated galvanized metal will remain corrosion free for years to come. Posts and panels are hot dip galvanized to ASTM 123. The ability of a galvanized coating to meet its primary objective of providing corrosion protection should be the chief criteria in evaluating its overall appearance and in determining its suitability. Hot dip galvanizing gives the fencing a greater resistance to corrosion than that obtained using other methods.
"The life expectancy of galvanized coating on typical structural members is far in excess of 50 years in most rural environments and 20 to 25 years plus, even in severe urban and coastal exposure."*
However, the process can leave minor impurities on the treated surface, i.e.., flashing, drips, drops, etc. These do not impair the coating in terms of corrosion resistance. Color and extra corrosion protection is then added on top of the galvanized finish by using a powder polyester coat.
Performance properties of the polyester coating is as follows. Salt spray resistance: (ASTM B_117) bonderite 1000 steel panels, in a scored condition, exhibit no undercutting after 500 hours in 5% salt spray testing at 95 degrees f. and 95% relative humidity with no rusting or blistering on panel face. Under the same conditions after 1000 hours the panels showed less than 3/16" undercutting.
(ASTM D-822) After one year exposure in south Florida with panels facing south and tilted at a 45 degree angle, a high gloss white polyester coating retains 88% of its gloss (gloss reading obtained on washed panels) with no film failure.
Ametco Mfg. Corp. certifies that its fencing systems are free from defects in material and workmanship. The polyester coated galvanized metal is guaranteed not to crack, peel or blister for a period of 20 years. Accidental damages, defects resulting from improper installation and damage from vandalism or abuse are not included. Allowance will be prorated over 20 years; maximum claim can not exceed original cost of coating.
*American Hot Dip Galvanziers Association, Inc.