While refurbishing an old worn dresser for my wife, I decided that the easiest and quickest way to get the job done would be with a few cans of spray paint. To give it a nice finish, I used a sealant, but couldn’t help but wonder if this was actually necessary.
While I know that sealant provides flexibility, extra protection, and gloss, it seemed like I could have gotten away with skipping this step. So, I decided to do some research and here is what I found.
In most cases, you do not have to seal spray paint. The only time where it is recommended to do so is if your piece will be in a high traffic area, handled frequently, or will be exposed to weather elements, as an extra layer of durability will protect it from scratches and chips. You may also use a specific type of sealant that has a glossy or matte finish to it.
What Do You Use To Seal Spray Paint?
As with any paint that you want to protect from scratches, chips, dents, and scuffs, a sealant or top coat should be used on any item you are spray painting that will be frequently handled or exposed to the elements.
The thing is, if you head to a paint shop and look at the aisle with the sealants, you are going to come across many different types. So, how do you know which one to use?
Here are 5 types of sealant and when to use them with spray paint.
- Shellac. This is an organic sealant made from the secretions of the female lac bug, and is combined with a solvent such as alcohol. This is a non-toxic sealant that gives wood items a nice, warm amber color. It does not stand up well to extreme heat, so don’t use this on items that may come into contact with heat, like a kitchen table.
- Polyurethane. This is a synthetic sealant that can be water or oil-based. The water based option is popular as it remains colorless after drying whereas the oil-based options can yellow your paint over time. If you get a fortified polyurethane water-based option, this can be applied on top of oil-based finishes. Keep in mind though, water-based polyurethane does not stand up well to heat.
- Varnish. A varnish sealant is a blend of oils and resins which contains a higher concentration of solids. This allows objects with a varnish finish to stand up to more physical wear and tear. It is great for outdoor use as it is water-proof and it provides natural UV protection.
- Lacquer. Modern lacquer is made up of synthetic polymers or acrylic resins which are dissolved in a mixture of solvents called a “lacquer thinner”. This is one of the thinnest options available and is one of the most durable. It can discolor over time and it can be scratched.
- Polycrylic. This is a water-based polyurethane sealant that has the added ability of being sprayable. It has all of the same advantages and disadvantages of a water-based polyurethane sealant.
All of these can be used over spray paint.
How To Seal Spray Paint on Wood
Wood can be sealed fairly easily, as most sealants are designed with wood in mind. Some general steps to follow include:
- Ensure that the paint is completely dry before starting.
- Using a 220-320 grit sandpaper, gently clear any raised spots and use a cloth to clear any debris.
- Avoid vigorous mixing, as creating any air bubbles can ruin your finish.
- Using a clean brush, spread sealant from edge to edge in a single direction. Going back on a stroke will result in an uneven finish. If you do notice any irregularities, smooth them out before things dry with the edge of your brush.
- After the sealant has dried completely, use more 220-320 grit sandpaper to smooth the surface. Remember to remove any debris afterward.
- Repeat these steps two more times for the best possible protective coating.
Keep in mind that these steps are merely general guidelines, so following the specific instructions of the sealant you use will provide a better finish.
How To Seal Spray Paint on Metal
Applying a metal sealant is very similar to applying a wood sealant, however, there are some key elements that separate the best metal sealants from the unusable ones.
- Metal sealants are typically used outdoors, so they need to be resistant to weather and sunlight.
- Additionally, the sealant must be flexible, as metals expand and contract with changing temperatures.
- Finally, metal sealants should be formulated to stick to painted metal. As with wood sealants, the metal surface to be sealed should be well prepared by removing any debris, such as rust or peeling paint.
How To Get a Smooth Finish With Spray Paint
One of the biggest issues with brush painting is that it can take hours to get the job done. With spray painting, not only can you eliminate the brush strokes that you would get with traditional painting, but you can also save yourself a ton of time as well.
While spray painting is convenient, it can be difficult to get a smooth, perfect finish. Here are 10 tips to help with this.
- Shake it and shake it some more! When you first go to use a new can, make sure to shake it for at least a full minute before beginning to spray. This will ensure that all of the paint is mixed in well.
- Test out the spray & nozzle first. Before spraying your object, test out the spray paint on a test subject first. This will allow you to test how well the nozzle sprays and whether the paint has become clogged or not. If the paint spits – does not spray evenly in a cone – try swapping the nozzle for another one. If the paint continues to spit, get a new can entirely.
- Don’t start or stop spraying on your object. A key technique to getting a smooth finish is to never start or stop spraying directly on your object. When you first begin spraying, the paint may spit out of the nozzle before it becomes uniform, causing a thick glob of paint to be placed directly on your object. Instead, start spraying away from your object and then slowly glide across the object from side to side. Always spray past the edge of your object to avoid having paint build up in one area.
- Don’t spray the paint vertically. When you spray the paint vertically on your object, gravity is going to pull on it. This is going to cause the paint to drip, even if you’ve sprayed as little as possible. It is much easier to get an even surface by spraying your object face up.
- You want each coat to be thin. You want to spray your object at a distance of 10-12 inches. This will allow you to apply a thin coat of paint. A thin coat will be less likely to drip as a result. Let your object dry for 20-40-minutes and then apply a second coat.
- Wipe down the nozzle. If you are spray painting for hours on end, make sure to pay attention to the nozzle. The paint can clog the nozzle up or drip around the outside of the can. Make sure to wipe it away and keep the nozzle area clear.
- Be careful when turning pieces over. When flipping your object over to get at the underside or the bare sides, be careful on where you set it down. The paint on the object itself may be dry enough to touch, but that doesn’t mean any excess paint on your backdrop is going to be dry. Flipping a piece into semi-dry paint will ruin the hard work you just put in.
- Don’t be afraid to sand it down to remove cracks & drips. No matter how careful you are, cracks and drips will happen. Don’t be afraid to grab some fine grit sandpaper to smooth away the blemishes. Just make sure to repaint the area!
- Don’t spray in direct sunlight. When working on your project, try not to use spray paint in direct sunlight. When you spray in direct sunlight or when the air is too humid, the paint can actually dry before it hits the surface of your object. This will cause little bumps to appear, giving you a non-smooth finish.
- On the last coat, use a new can. When you are on your last coat of spray paint, break open a new can and shake it well. Make sure to test it before you start using it to apply your last thin coat. Why a new can? The spray is going to be uniform, the nozzle won’t be blocked, and the paint will come out more evenly.
As with any technique, it will take you some time to nail it down so keep practicing.
What’s the Difference Between a Primer and a Sealer?
The main difference between a primer and a sealer is that a primer is the first coat of paint applied directly to the substrate surface which helps the topcoat bind to it, whereas, a sealant is used to prevent previous paint from bleeding through, moisture from getting in, or stop undue absorption of the topcoat into the substrate. Sometimes a sealant can be used in place of or prior to a primer being put down on the substrate.