Polyurethane will create a good, hard finish on the wood you apply it to. It’s easy to apply by using a brush, but it’s something that you need to use safely. Used correctly, there are no dangers associated with polyurethane. The trick is in knowing how to use it properly.
When working around polyurethane, you need to make sure nobody is smoking and that there are no open flames. This should be a standard procedure when working with any material or liquid that could be flammable.
The last thing you want to risk is a fire, especially since you’ll usually be working in an enclosed space irrespective of how well ventilated it is. As a precaution, you should keep a fire extinguisher and fire blanket in your workshop because fires can start for many reasons. Make sure you only smoke outdoors, away from your workshop or any sawdust and flammable liquids.
When working with anything that produces strong fumes, you will need a face mask to protect your throat. Breathing in strong fumes may burn your throat and lungs and can lead to dizziness. Some prefer to use more than a basic mask but air-fed alternatives are available, although you should be fine using a paper dust mask when working with polyurethane.
Face masks should always be part of your safety routine when working with liquids that emit strong fumes. Always follow manufacturer instructions to maximize health and safety conditions in your workshop.
Since polyurethane can be an irritant to the eyes, you should always wear safety goggles when working with it. You will be brushing the liquid onto the wood, so safety goggles will ensure that no small drops or splashes end up in your eyes. Again, safety goggles should be a standard part of your safety routine when working with liquids that can splash. Vision is precious, and it can easily be ruined or even lost.
You should make sure you work in a well-ventilated area to ensure fumes don’t build up when you’re working with polyurethane. Whenever you’re painting or working with anything where fumes are in evidence, you will need to ensure that the work area has ample ventilation to facilitate easier breathing. Working outside is best but this won’t always be possible.
It’s important to be very thorough in cleaning up when you work with polyurethane. Being sloppy and leaving cans open can make fire more of a possibility. It will also let the fumes escape into the air. A spill that’s not cleaned up properly doesn't only make the floor sticky for walking, but it also increases the fire risk.
If you’re using oil-based polyurethane, you’ll need to have paint thinner or mineral spirits available or you won’t be able to remove any excess material that occurs while working. Be careful with paint thinner because it’s a very flammable liquid and spills can be hard to clean up. With oil-based polyurethane, always dilute the polyurethane with mineral spirits before using it.