If you have ever used spray paint on furniture, cabinets, or other surfaces, you may notice an issue commonly called “fisheyes.”
These are defects that show up as small, circular shapes that have a crater or depression in the center. You may see them as white dots or simple circles of paint with a separation around them.
You may also know them as pits, craters, or saucers. They look a lot like the eyes of fish, and that is where the fisheye name comes from.
Why Does Paint Fisheye Occur?
A fisheye tends to show up when you apply a coat of paint to the surface or just after the surface has been coated.
Most of the time the cause of the fisheye is a contaminant, something on the surface that reacts to the paint being applied. Such contaminants can vary, but the main ones are chemicals, oil, water, and substances that are silicone-based in nature.
If any of these contaminants have found their way to the surface or have been trapped in your paint gun, you will most likely face fisheyes problem when painting.
Besides surface contamination, coating too thin can sometimes cause fish eyes and pin holes. This is mainly observed in epoxy resin coatings when poured less than the recommended depth.
Removing Fisheye Craters from the Surface
You can always clean the surface, which rids the area of fisheye, but that does not always work if the paint reacts to a contaminant that is inside the cracks of the wood.
If you see a fisheye developing, the first step should be to remove the contaminant. Just trying to cover over the paint with another layer of paint only means you are creating yet another fisheye.
It can be quite tedious to remove the craters and the contaminants if you have many fisheyes on the surface.
It’s one thing if you only must remove one or two, but dozens can make the effort that seems not worth it. So, in that case, you should consider removing all the paint before cleaning the surface thoroughly and trying again.
Method 1- Sanding or Stripping
The best way to remove paint and lacquer fisheye is to sand the area to remove the contaminant and then use a stripper or thinner to get rid of the finish.
If you have coarse grit sandpaper, this will work quite well. However, you must be careful not to damage the surface. Otherwise, a chemical stripper is recommended. But always try sanding first as that is the most effective way to remove the paint and the contamination.
You can try a combination of 220-grit sandpaper and lacquer thinner if you are spraying pre-catalyzed lacquer on the surface. This should remove all the spots on the wood.
If the fisheye forms over a knot in the wood, it means that some type of contaminant is trapped inside the knot or cracks. If that contamination is deep enough, it will be almost impossible to remove. However, there is a spraying technique that can solve this problem.
Method 2 – Fisheye Eliminator
This is a chemical additive used to remove the surface tension, which usually contributes to creating fisheye. To get rid of the problem you will need to choose a fisheye eliminator that compliments the paint or clear coat lacquer you spray.
Sherwin Williams suggests not to use fisheye eliminator in undercoats or basecoat colors. If you see fisheyes appearing in a basecoat, you should instead allow the color to flash and then spray a mist coat over the affected area to fix the fish eye problem.
In case the paint has already dried, it’s better to sand the surface to a smooth finish below the fisheye cratering and then refinish.
The additive is something you should only use if everything else has failed because although it is effective it will add silicone and other chemicals into the sprayer. So, it may work on your present project, but for future projects, it will create fisheyes unless you thoroughly clean the lines.
How Can You Prevent Fisheyes from Happening?
To prevent fisheye occurrences, it is imperative to acquire basic application techniques. The foremost step entails meticulous maintenance of your equipment used for painting, varnishing, powder coating, or other finishes.
- For spray painting, employ an air filtration system to avert paint contamination. Utilizing a reliable separator and air filter on your compressor can significantly diminish the risk of contamination.
- Regular maintenance of your air compressor is highly recommended. This includes cleaning the intake valves, replacing the air filter, and draining any condensation. By doing so, you effectively reduce the likelihood of contaminants infiltrating the paint.
- Furthermore, inspect and meticulously clean the HVLP paint gun after each use. Also, ensure thorough cleaning between coats. Neglecting proper cleaning procedures will inevitably result in fisheye formations.
Always spray light mist coats to prevent fish eyes
Instead of layering one or two heavy coats on the surface, try applying several lighter coats first and let them dry. Then if you need to, apply a heavier coat.
This method can work for lacquer or paint- but it can be time-consuming, especially if you have a large project to complete within a specific deadline. Be sure to lightly sand between mist coats for an even smoother finish.
Cleaning to avoid fish eye paint problems in the paint
To prevent contamination from being on the surface, it’s imperative to clean it properly before applying any finish. Products such as Krud Klutter or TSP are pretty good at removing most forms of contamination, according to dengarden.
Be sure to use a coarse cleaning pad to scrub the surface with the cleaner and then rinse with clean or purified water. This is especially true when using TSP, as all residues must be removed entirely.
Another cause of fisheyes is having a silicone-based substance get into the metal or on the surface of the project that you are painting. To help avoid this possibility, use a paint prep solvent before priming and painting. This will clear away any impurities that might’ve found their way onto the surface.
The Bottom Line
Fisheye is a frustrating issue that can ruin your project’s appearance. However, with careful and meticulous attention to detail, maintaining your equipment and thoroughly cleaning the surface before applying any finishes, you will be able to avoid fisheye formations.
Of course, all the preparation in the world may not entirely prevent fisheyes from appearing. So, before you attempt any technique for prevention or removal, it is crucial to understand what causes fisheye in the first place. This way, you can successfully identify and eliminate the source of fisheye before it gets out of hand.
Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.