Polyurethane finish comes in various types. You can find it in water-based or oil-based finish. It is available in various paint finishes like satin, semi-gloss, and high-gloss finish. This is a plastic-based resin, which can be applied to various materials like plastic, fiberglass, metal, fabrics, etc. But, it is mostly used to apply on wooden objects. Applying this finish to various objects increases their life. Polyurethane is resistant to water and chemicals, even to chemicals like gasoline. It comes in various types, and hence it is important that you read the label properly to check if it is floor finish or exterior finish.
The solvent-based finish undergoes a chemical reaction when it is allowed to cure. The chemical reaction leads the polymers to bond strongly to each other, and once this process is completed, even mineral spirits can't be used to remove the finish from the surface. While working with solvent-based polyurethane finish one needs to take care to work in a well-ventilated area, as the fumes will evaporate from the piece of furniture surface.
While the water-based finish is quick to dry and easy to clean; still one needs to work in a well-ventilated area, because milder fumes will still be released from this finish. When staining hardwood floors or other wooden furniture with this finish, it is important that you wear a proper mask and safety goggles and other safety gear to protect your skin from coming in contact with this finish. Fabric or paper mask won't be able to filter the fumes, so avoid using them. Also, avoid using it anywhere near exposed flame or furnaces, as it tends to be extremely flammable.
Availability and Features
This finish is available in buckets or in small spray cans. It is available as a clear topcoat or in many colors. You can find this finish in spray cans in many hobby shops. The finish of polyurethane will be very thick, hard, and glossy similar to car finish. It is ideal for model making as it gives a nice flawless glossy finish and is resistant to many liquids. This also makes it ideal for refinishing furniture.
Applying the Finish
Thinking, how to stain wood? Proper preparation is the key. Also, when using polyurethane for large projects the finish and drying catalyst need to be mixed properly, otherwise the resultant finish can bubble up and crack with use. When using it for refinishing hardwood floors or finishing new wooden surfaces for the first time, you need to clean the surface properly first. Here are tips that will help in applying the finish on hardwood floors or other large wooden areas.
Start by sanding the wood, then with a vacuum cleaner clean up all the dust. Then use a lint-free cloth and wipe the surface, ensure that the surface is clean and no dust or debris are on it. Then apply a thin coat of the finish and allow it to cure. The water-based finish will take around an hour to dry, while the solvent-based ones can take around four hours to dry. If you stay in a humid area, then it will take longer for the surface to dry. Then again clean the surface properly and apply another coat of the finish. After you are done with the coat let it cure. Remember that several thin coats work better, than applying one or two thick coats, so work in several thin coats. Make sure you keep sanding and cleaning between each coat and let the previous coat dry before applying the new one.
So, buy the clear or the tinted variety of polyurethane finish in cans or in buckets. Remember to prepare the surface well, before you apply the finish to achieve a smooth, glossy surface.