One of the favorite materials used for wood finishing and floor finishing is the Polyurethane. This is used as a shielded coating for some projects like wooden projects. The reason for using this material for wooden and floor finishing is it provides high durability and hard gloss for the surface. Another reason for using this is the paints made with polyurethane can be applied to any surface.
One of the general questions arises to many users while using this material for painting is how to spray Polyurethane? In general, there are various kinds of this material available in the market. Based on the formulation of this compound and some other factors spraying polyurethane varies. As it is available in different types, spraying this material also differs. The forecast use and the size of the project fix the best method of application and form of finish.
Spraying this material depends on the surface for which it is used for, the formulation used with its water or spills, exposure of the sunlight etc. Based on these the uses of polyurethane also change. It serves as a good heat resistant which makes it as a good kitchen furniture coat. Another question related to this spraying is whether it can be sprayed perfectly or not. It is a coating material which is normally used to protect wooden surfaces. Once used it offers a number of benefits to the user and that’s the reason why most of the people consider polyurethane for their wooden coating.
Gun Spray Paint
Water Based Polyurethane vs Oil-Based Polyurethane
Before going to apply polyurethane for the surface and know how to spray this material, first we have to decide which type polyurethane is best, water based or oil based? Both type of polyurethane are best in its own way and exhibit different qualities. Both models are highly durable and offer good look to the surface, but there are some differences between them. You have to choose the right one for your project
The first difference between these two types is the drying time. Water-based polyurethanes take a less time to dry, on the other hand, oil-based polyurethanes take quite much time to dry. Once sprayed, the water-based polyurethanes take two hours, and you can recoat them and clean with water. Even you can sleep in the room overnight. But, the oil-based polyurethane takes five to twelve hours to dry. This is a long time and you can use your room only after this time
The next factor to consider is the finishing effect. When comparing these two, the polyurethanes based on water won’t give an excellent finish to the surface. Whereas the polyurethanes made with oil provide an amber glow to the surface. Also, the water-based polyurethanes offer a perfect finish on its final coat. While oil-based polyurethane requires fewer layers for a final finish. Thus, at the finishing point, the oil-based polyurethanes are best than the water-based one.
The working environment for these two types also differs. As the water-based Polyurethanes dry quickly, one can use this in any working environment. The oil-based polyurethanes take much time to dry, therefore, one should live in a working environment that should be clean and dirt or bugs free. This is because if the working environment is not clean in the case of oil-based polyurethane then, as the time goes the insects and dust get to stick to the surface. This will affect the quality of the work and finish.
After spraying, the water-based polyurethanes need two or three touchups. That is after drying you need to give another coat to the surface in order to achieve a good finish. But, oil-based polyurethanes are best in this aspect. It gives a good glow and looks to the surface on its first coat and it does not require any additional coats. Fewer coats are enough in the case of oil-based polyurethanes.
The water-based polyurethanes has only 30 to 35 solid percent of solids, whereas the oil-based polyurethanes contains 45 percent to 50 solids. Therefore, water-based polyurethanes need extra coats when as it includes small solid percent. This is because these solids are the factors that give an excellent protective finish.
The most important one to consider is the cost. When coming to the price, water-based polyurethanes cost more than the oil based one. The cost of water-based polyurethanes is twice more than the cost of oil based. Therefore, if you are money concern you can go for oil based polyurethanes
The polyurethanes based on the water lasts for a long time than the oil-based ones. This is because as these polyurethanes require more coats than oil based one, it has a long life. Whereas, the oil-based polyurethanes need only fewer coats and fade soon.
Tools and Materials
Following are the tools and materials needed for this project
Before going to start your spray you need necessary tools. This will help you to avoid frustration at the time of painting and it will save your time to a greater extent. The tools needed for spraying this polyurethane are
- Roller tray
- Floor finish applicator and
- Knee pads
In the case of polyurethanes based on oil, you need a brush with a fine bristle and a foam brush and clean cloth.
Like the tools you also need to make arrangements for you materials also. The following materials are required
- In the case of polyurethanes based on oil paint thinner is required
How to Spray Polyurethane Paint?
So far we have seen about polyurethanes, its type and which one is better water-based one or oil based one. Now we are moving into the spray. Let us see how to spray polyurethane paint. This step by step guide will be very useful for you if you are in need of spraying polyurethane paint for your wooden painting project or any other surface painting project. Follow the below given steps
Step 1: Set up the work area
The first and foremost step you need to do is to set up your work area. Make arrangements for the area on which you are going to work. You have to concentrate on your working area whether it is clean or not. A clean working area is needed for spraying this material. Also, keep all the things required at the time of spraying nearer to you but not so most adjacent. This will be very helpful for you at the time of painting
Step 2: Surface preparation
After setting up the working area, you need to prepare the surface on which you are going to spray your polyurethane paint. Keep the surface area clean and dirt free. If there is any dust or bugs on the surface then you can’t able to get the perfect finish. It is better to clean the surface area with a neat cloth before spraying. This will remove any dust or dirt on the surface and the paint will sits perfectly on the surface. Keep in mind that a well cleaned surface is must
Step 3: Spraying
Before starting your spray, prepare the spraying material correctly. As polyurethanes need thicker coats, you need the help of thinner. But, first spray the paint without using thinner and see the finish. Based on the finish consider whether you need to add thinner or not and then add it.
In order to attain good finish, you have to spray the paint in thinner coats. This is because thinner coats will give a good finish and removes ruins. Between your layers, and the surface. This will provide a surface for the next round of coat. Spray a number of thins coats and this will give the thicker coat that you want to achieve
Step 4: Drying and Cleaning
After successfully spraying your paint, allow it to dry. Let it take some time to dry. Once the surface is dried, clean your surface with water. If you use oil-based polyurethanes it takes quite a much time to dry. Hence, check once the surface is dry or not and then clean the surface.
Tips for Safely Spraying Polyurethane
- While spraying polyurethane on vertical surfaces, you need to be careful of runs and drips.
- It is better to spray thinner coats on these types of surface
- Even though you face a run, you have to handle this with extra care.
- Use some sharp razor blades to remove this run and to achieve a clean finish
- Before starting your spray, be prepared with all the safety measures
- Also, while applying the paint you have to look at different angles. This will help you achieve a perfect finish
- Always do your painting work in a clear light and stand in the reflective direction of the surface and look at various angles
- This will help you identify your areas that are missed and over brushed. Hence, you can correct those areas and attain a perfect finish
Can You Spray Polyurethane
Yes, it is possible. To get the best finish when spraying polyurethane, you should try to apply a thin coat (as thin as possible). This will mean using smaller fluid nozzles (1-1.4mm) or air assist airless nozzle sizes and making a swifter pass over the product surface. A thin coat will help to reduce or eliminate issues such as runs in the finish.
In between different coats of polyurethane, you should sand (with about a 220 Grit sandpaper) to provide a better surface for the next coat. You will build your desired thickness by spraying multiple thin coats.
If you want to use a water-based polyurethane, first raise the grain then sand it down before you apply the first coat of polyurethane. This will prevent raised grain which can produce an ugly surface. You should also be careful and avoid applying too many coats; the recommended number of polyurethane coats is four.
Your technique will also have an impact on the quality of the surface you get. If you want to use a spray gun, hold it closer to the surface; if you use an air assist airless, hold it further from the surface. Polyurethanes are usually slower drying coats when compared to other finishes. The additional time needed for it to dry will require you to keep the product away from other products and dust.
By considering your application technique, equipment, characteristics of your polyurethane, and where you spray, you can rest assured that you will apply your coat in an efficient way and look better.
Spraying Water Based Polyurethane
Switching to water-based polyurethane from solvent one has some benefits, mainly reduced fire hazard and odor, as well as minimal effect to the environment. However, the switch can be hard because it’s harder to apply water-based polyurethane.
It is true that pulling the release on the gun and covering the area while moving the gun is pretty the same, but there are some notable differences that can result in problems that can discourage the switch.
You might experience some issues. Don’t worry we have solved them below.
- Be diligent – Before you even begin to spray, you need to be diligent to avoid staining the surface.
- Atomizing – Water-based coating doesn’t atomize easily, especially when the finish is cold. Therefore, use air-assisted airless and airless, especially the former. You can even thin water-based coating with water to enhance atomization.
- Better prep – You should pay close attention to sanding the initial coating before you add the second layer. Once the first coating is smooth, the rest will flow smoothly.
- Drying – Water-based coatings dry slower than other brands. This is specially made complicated by the mere fact that you cannot add any solvent to speed the drying process. The easiest way to speed up drying is to use heat or increase airflow.
- Cleaning – One of the challenges of switching to water-based finish is the heightened difficulty of cleaning the equipment and spray guns. The best solutions to this are: dismantling your guns and then scrubbing the finish of every part using a brush. Using a gun-cleaning solvent sold by spray gun or finish manufacturer.
On the whole, if you want to achieve a perfect polyurethane finish for your surface, you have to concentrate on all the factors mentioned above. Starting from the type of polyurethane to the surface area you need to focus each and everything. Then only you will be able to attain the productivity of your painting project. Thus, clearly arrange all the needed things, make your spray, pat it dry, recoat it, and finally clean your surface and enjoy it.
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