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Preparing Metal Pools for Morris Water Maze

Lots of users now use galvanized pools as a cheap robust solution for Morris Water Maze Pools.

These will need painting. For dark & hooded animals use 'milk', & paint your pool white. For albinos, use clear water, &  paint your pool black (preferably non-glossy). The problem is that regular paint just peels off after a short while. So here is what to do.

Painting galvanized steel requires careful preparation and a good understanding of the process to achieve good adhesion. To avoid paint adhesion failures you need to follow  the ASTM D 6386 specification.

Typically you tank will not have been hot-dip galvanized after within the past 48 hours so it won't have the very smooth surface without no zinc oxides or zinc hydroxides needed for commercial treatment of galvanized surfaces. 

Before painting galvanized steel tanks, it is important to know if the coating was chromate quenched. If you can't spot testing the galvanized steel according to ASTM B 201 to determine chromate conversion coatings. You can ask the manufacturer as the chromate layer must be removed, either by brushing off by abrasive blast cleaning, abrading, sanding. In either case galvanized steel also should be slightly roughened to improve paint adhesion. 

You can then remove oil, grease and dirt using an alkaline solution in the pH range of 11-12, but not greater than 13. An alkaline solution is nominally 5 to 10 percent sodium hydroxide compounds with small additions of emulsifying or chelating agents. The solution can be applied through dipping, spraying or brushing. If brushing, use a soft bristle nylon brush. After cleaning, thoroughly rinse the surface with hot water and allow to dry completely. Alternatively you can use an organic solvent, mineral spirits, turpentine or high-flash naphthaand then thoroughly rinse the surface with hot water and allow surface to dry completely.

You can then treat with Zinc Phosphate Treatment to increase the adherence and durability of the paint film. The phosphate treatment can be applied with soft bristle nylon brush and left on the galvanized steel between three and six minutes. The pool should then be washed with clean water and allowed to completely dry. Alternatively use an acidic acrylic solution to passivate the galvanized surface, as well as promote paint adhesion. 

Finally use an Epoxy-Polyamide Cured paint as these have superior adherence to galvanized steel and won't peel or flake in use. Best of all use a Powder Coating.

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