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There are 3 basic paint types but we need to expand it further. From time to time home carvers indicate they would like to paint their creation with Acrylic Lacquer. This material, like 2 pack, is primarily formulated for use on metal, not wood! As a general rule, the faster it dries, the more it shrinks, because there are more thinners than paint! Enamels will ‘flood’ into a hollow and fill it to give a smoother surface and also not be affected by temperature as much as lacquer. In cool or humid weather, lacquer will ‘bloom’ and show a misty finish. Before acrylics came on the market, lacquers were amyl acetate based, like nail polishes. The amyl acetate was extracted from banana skins but like most products today, they have been synthesized. What we see and the quality of the finish is very dependant on how good the base is. It is also important that each layer is compatible with the ones next to it. Vinyl (plastic) finishes will not adhere to an oil-based undercoat. The lacquer thinners will eat into any enamel it is placed over. Have you ever seen an automobile where the paint looks like it has had hair thrown on it? Very fine cracks! This is called ‘Plasticer migration’ where the flexible agent that allows the topcoat to expand and contract without cracking, has migrated into the undercoat. WHY? Because the wrong undercoat was used! To stop it re-occurring, you coat the surface with a spirit based product so the solvents in the new undercoat cannot penetrate. This ‘shield’ must not be sanded, as the fine scratches would allow the solvents access to the coat underneath! Spirits and solvents are different! The chemical formulae today are very complex and returning paint that has been thinned with Mineral Turpentine to a tin of unused product is likely to cause the entire contents to jellify! Paint that is exposed to air goes hard, so the larger the area of air to paint in a tin, the quicker it will solidify. Turning the tin upside down to store it only allows the solids in the material to be resting on the underside of the lid. The percentage of air is the same! Put what is left of the not thinned material in a smaller container if you want to keep it. Have you ever noticed cars with a light Grey undercoat that have been over coated lightly with Black? The Black is a ‘guide coat’ that will be evident when you sand it off. Any Black left will be lower than the surrounding surface, indicating a deep scratch or a hollow that needs filling. Stained horses will require a similar treatment but a different range of products. After the light application of a coloured stain one will notice lots of scratches that were not evident before, particularly glue residue. These will show as shiny patches as the stain is on top of the glue residue, which stops it from soaking into the timber. It is advisable to sand the whole horse back to an even colour before the selected stain is applied. There are quite a number of modern stains; some are incorporated in the gloss finish but these are not recommended. I highlight my horses with a black stain on the hoof, ears and nose areas, but mask the teeth and shoes I carve into the hoof, so they remain white and stand out. I, of course use a spray gun! There are Water Based stains and clear coats in the vinyl range, cheap but so is the finished job! I use a Sanding sealer over the stain. This will stand the furry surface of the wood up, so when it is sanded, the sandpaper will cut the stiffened fur off instead of merely laying in down to spring back up. Apply it to an area and rub your hand over the wet sealer. This will force the sealer into the millions of minute holes to block them and at the same time smooth down the fur. This means less sanding, which must be a help in the long run as each time that the sandpaper cuts through the coat it has to be recoated to seal it again. 3 coats of sanding sealer with a rub between the first two coats with paper and the final rub with steel wool before applying 2 coats of clear polyurethane. A satin finish will not show as many faults as a shiny one. Do not forget to remove the masking tape from the teeth and horseshoe areas before applying the first coat of sanding sealer. There are no shortcuts to getting a finish that will enhance your work and protect it for many, many years into the future. |
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Painting Horses Part 1 |
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