Polyurethane Over Paint
In terms of how hard Polyurethane is, it falls somewhere between rubber and plastic. It is a great product that can be used for a variety of reasons. You might opt for Polyurethane over rubber or plastic due to its durability, the fact that you can adjust its hardness or even that it has impact resistance that beats either of the other two. Here is a look at why you might opt for Polyurethane over paint, some advantages it has and then some tips on using it.
As mentioned you get a lot better durability when using polyurethane instead of rubber or plastic. But it can even be used instead of steel too because another advantage is it will not rust. In some situations polyurethane has outperformed by as high as 8 to 1 rubber and plastic. It is not affected by mold or mildew or fungus, it has stability when wet and is less likely to deteriorate or swell. This means when it comes to moist or damp conditions Polyurethane makes the best application option. It can also hold its own in cold environments, hot environments and when it is older.
The fact that it lasts longer means that when you use polyurethane you will need to replace it less often than other options. This means it is less work and more cost effective. Your productivity is improved by being more efficient and having to spend less time on certain replacement or repairs. It can be used to add protection to a material and extends its life, and can bond to many materials like fabric, wood and metal. Since coatings can be in different colors you can also make the equipment or structure look better.
For example by applying polyurethane to something painted you can protect the paint under it. One or two coats is enough and to avoid issues about color use a water based option. Though with oil based polyurethane you do get a smoother finish but it takes at least a few hours longer to dry than the water based ones. You can use it over any type of paint, just make sure it has been prepared and cleaned.
Using Polyurethane on Paint
Here are some tips on using polyurethane over paint, how to prepare and apply it.
- If you have just finished painting leave it to sure before you add a coat of polyurethane. Curing times range depending on the conditions and the type of paint but a week should be a good time to wait.
- If the paint is not fresh you need to wash the surface before putting on an application. Use a strong detergent such as a gallon of water that is warm with ½ a cup of trisodium phosphate. Get off any stains and grease especially using a rag or sponge. This will also help de-gloss as well as clean which will let the polyurethane adhere much better to the paint when it is time.
- After washing leave it to completely dry. Then using a 120 grit sandpaper scuff the paint. You want to take on the sheen of the paint but not create any deep scratches that would then be obvious under the polyurethane. This can be dome with either a palm sander or by hand. If it is a painted floor you are working on use a floor buffer with a sanding screen of 120 grit. Then using a cloth or damp rag wipe away any sanding dust left there.
- You can apply the polyurethane whether it is oil or water based, using a brush or by spraying it. It is not a good idea to use a roller because this can lead to lost of bubbles left in the finish that might harden and then ruin the finish. If you opt to spray do not thin out the polyurethane, it is already thin enough to be sprayed and if you dilute it any more it could make it run and again ruin the finish.
- Once you have applied one coat you should leave it to dry for however long the instructions suggest. Then using that 120 grit sandpaper scuff it lightly to take away tiny particles of dust and to flatten bubbles.
- Put on your second coat the same way you applied the first. Two coats is enough. Let the second coat dry again for whatever time is recommended but then give it another 24 hours to fully harden before you handle it or walk on it.