Take a clean cloth, add some mineral spirits and wipe the surface to remove dust and dirt. Repeat the same wiping process until the stains are gone and allow the surface to dry. Sand the surface with fine grit sandpaper (220 grit) until the haze disappears and the polyurethane coating is removed.
Actually, this is good advice for any finishing job. Spirits. Saturate a clean cloth or buff with mineral spirits. Wipe the affected area through the first layer; Allow to dry, soak the cloth or sponge again and repeat this process until you reach the stain.
Cloudy surfaces occur for a number of reasons, including using an old product or one that has been stored in a very cold or hot environment. Also, for proper application, it is necessary to stir the polyurethane coating immediately prior to application to the surface, which should be clean and oil-free.
White spots on polyurethane are generally caused by two things: not stirring thoroughly before applying, or moisture build-up. While preventing the white spots is easier than fixing them, you can fix them by sanding down the high spots and then pulling out the moisture.
Before you get upset, check that the polyurethane has actually dried. When using water-based material, it’s common for it to appear milky before it dries. The color comes from the emulsion that carries the resins. If the finish is still damp, just wait – the milkiness should disappear.
High humidity can cause the clear coat or base to appear cloudy or milky.
Polish the surface lightly and evenly with # 0000 steel wool dipped in linseed oil. Work with the grain of the wood and rub evenly over the entire surface until the white haze disappears. Then wipe the wood clean with a soft cloth, apply two coats of hard furniture wax and polish to a high gloss.
With some types of poly, nothing will happen if you don’t sand between the polyurethane layers. However, most polyurethanes won’t bond properly if you skip sanding dust specs and brush marks on the surface. The polyurethane finish will eventually peel or warp.
Mineral mineral spirits will not attack polyurethane, so a rejuvenator is needed for this. This is simply paint stripper diluted with solvent. This softens the polyurethane, allowing part of the upper to be wiped clean. You can’t revive a finish if it’s thin, flaky, checkered, or alligator; You must remove it.
Mix a one-to-one ratio of water and vinegar, dampen a cloth and rub away the cloudy deposits. Rinse with another cloth dampened with clean water and dry the floor immediately with a third cloth. Washing combined with wear and tear can eventually make the parquet floor look old and dull.
Removing Old Paintwork and Sand
You will achieve the best results from your topcoat if you remove old paint, varnish or other finishes before applying polyurethane. For a smooth finish, the surface should be as smooth as possible, so prepare the wood by sanding it with a sanding block or orbital sander.
If you find that your wood has become really dull from a build-up of furniture polish, you’ll see a haze or streak that you can’t get rid of. You can either apply a plant-based enzyme cleaner and leave on the wood for a few minutes to remove the buildup, then wipe with a cotton cloth and buff dry.
Start by sanding away the old clear coat. Once the old clear coat is removed, you can reapply a new clear coat. If you need to blend the old clear coat with the new, lightly sand the area and polish your car like new.