We may receive a commission when you use our affiliate links. However, this does not affect our recommendations.
The tools are the easiest part of finishing to understand.
Compared to woodworking, finishing is a very simple craft. The goal is no more complicated than transferring a liquid stain or finish from a can or other container to the wood. There are only three tools used to do this: a rag, a brush, and a spray gun. (I include rollers, paint pads, etc. In the same category with brushes). Each is easy to use. Even a spray gun is no more complicated than a router.
Since many carpenters struggle with finishing, despite what I’m saying in this article, I have to include this caveat: choosing which stain or finish to use and how to use it can be confusing. This is largely due to the manufacturer’s poor labeling, but there is
no problem understanding the tools.
There are five key differences between the three tools: cost, transfer rate, degree of production of a layer film, relative amount of waste produced, and weather issues.
with a spray gun.
Rags cost little or nothing, especially if you strive to save old worn cotton clothes. Additionally, inexpensive paper napkins can often be substituted for small jobs. Brushes are also cheap, although they cost more than rags. Conversely, even the cheapest spray guns, combined with a high-volume or high-pressure air source, cost $ 200 or more. So, if cost is a factor, you might want to stick to using rags and brushes.
The exception is with small items where you may be able to use aerosols. These are widely available in almost all finishes.
You can apply a stain or finish over a large area faster with a rag or spray gun than with a brush. Rags are very effective when you intend to remove all the excess, as you usually do with stains and oil finishes. Spray guns are effective for applying any stain or finish and removing excess or leaving a finish to build a film.
By comparison, brushes are inefficient tools, because they can only carry a small amount of stain or liquid finish at a time. You have to constantly dip the brush into the liquid to refill it.
Leveling the film
In cases where you are not blotting out the excess, final leveling is very important. You can always sand the finish to remove defects, such as brush marks and orange peel, and make it level. But this takes extra work and always carries with it the risk of cutting and causing hard-to-repair damage. The goal in applying any milestone is to make it as leveled as possible from the start. The three tools differ in their ability to produce a level film.
It is almost impossible to apply a film construction finish with a rag without leaving deep grooves in the film. (The exception is when using the French polishing technique, which can only be done with shellac.) Brushes perform better, but leave brush marks. This is also true with sponge brushes, which leave ridges at the edges of each stroke, and with expensive bristle brushes. Spray guns produce the flattest surface of the three tools. But even spray guns leave a slight pimply consistency called “orange peel”.
Hence, it is virtually impossible to apply a perfect finish using any tool unless you remove all the excess after each coat. All three tools leave defects in the finishing film. To make a finish perfect, you need to level it with sandpaper, then scrub it down to the sheen you want using steel wool or rubbing compounds. It usually takes much less work to sand a finish layer applied with a spray gun than one applied with a brush.
Waste is undesirable due to the cost and amount of pollution it creates. Waste costs more, not only because of the unused finishing material, most of which ends up in the atmosphere, on the floor or on the spray booth filters, but also because of the cost of disposing of used solvents and filters.
Rags and brushes are almost 100% efficient. In comparison, spray guns are very inefficient. Much of the finishing material is lost in overspray and rebound. HVLP spray guns are more efficient than older conventional spray guns and therefore HVLP guns dominate the market.
If you live in a cold climate and can’t get outdoors most of the year, you’ll have trouble using a spray gun. Spray guns create a lot of overspray that floats around the room and lands on everything including your work. You need to run out of overspray and this presents two problems: replacing the exhausted air with hot air and trapping the overspray before it gets to the fan and builds up on it. Conversely, rags and brushes efficiently transfer all the liquid from the can to the wood. The only residue is the evaporation of the solvent as the coating dries.
Replacing warm air with warm air on cold days can be a strain on your heating system. Placing a stove in the room you are spraying can be a danger, especially if there is a flame in the stove. Never spray in a room where there is an open flame as it can cause an explosion.
To trap the overspray, place a series of filters between you and the exhaust fan. Don’t let the finish or paint build up on the fan. Also, prevent solvents from a solvent-based paint or finish from being drawn into an engine that is not explosion-proof.
Although spray guns are easy to use and produce good results, few hobbyists rely on them because of these problems. The most common tools used by hobbyists are rags and brushes.
Here are some supplies and tools that we believe are essential in our daily shop work. We may receive a commission from sales reported by our links; however, we have carefully selected these products for their usefulness and quality.