Matt is a professional painter who owns and operates his own painting business, specializing in interior and exterior house painting.
What Causes Fisheye in Paint and Lacquer?
If you spray paint cabinets and furniture enough, you will eventually run into problems with fisheye. This annoying problem is often resolved simply by cleaning the surface, but that doesn't always work if your paint is reacting with a contaminant trapped inside the cracks of the wood.
Sometimes the only way to stop a bad case of fisheye is to use a simple application technique, which I cover in this article. I had a fisheye nightmare once spraying pre-catalyzed lacquer on a large set of cherry cabinets. I was able to fix it, but finding a solution was a very frustrating experience. Now when I encounter this problem, I know how to handle it.
Before you attempt a fix, it's important to understand what causes the problem in the first place. Here are some common causes for fisheye in paint and lacquer:
Common Causes for Fisheye in Paint
- Not rinsing the surface after cleaning
Fisheye defects form when paint comes into contact with surface contamination. Instead of flowing evenly over the surface, paint flows around the contaminant to form the dreaded fisheye spots, which look like small craters. Lacquer is said to be more prone to this problem than paint, and although I had a bad experience once with lacquer, I run into this problem more when spraying acrylic alkyd enamel.
Silicone Oil from Furniture Cleaner
Silicone oil and wax contamination are two common causes of fisheye when painting cabinets and furniture. Silicone oil is found in household wood cleaners and furniture polish, including Pledge. The oil is usually removed if you clean the surface correctly in the beginning, but sometimes the oil gets trapped inside wood knots, or worse, inside the grain.
If you're painting wood that was previously buffed with wood polish or cleaner containing silicone and wax, the fisheye is likely the result of contamination from those chemicals, but there are other causes too.
Oil Inside Your Air Compressor
Unless you're using an oil-free air compressor to remove sanding dust from your substrate, it is possible for oil inside the compression chamber to end up on the surface when you use the blow gun. It is also possible for moisture to end up on the surface if you don't use an in-line filter to catch it, or if you don't drain accumulated water from your compressor tank. Water is guaranteed to cause problems with solvent-based coatings like lacquer.
Not Rinsing Enough
Residue from pre-paint cleaners, especially TSP, will cause fisheye if you don't rinse thoroughly with clean water. There are cleaning products advertised as "no rinse" but rinsing anyway is a safer measure. I prefer using cleaners that won't streak or leave a lot of residue on the surface. The wood cleaner I use a lot with good results is Dirtex powder cleaner in the box, not the spray bottle.
Fisheye is also caused from a surface not being cleaned good enough in the first place. Heavy grease and grime calls for a strong de-greaser. When I clean greasy cabinets, I grab a bottle of Krud Kutter Orginal. This stuff cuts through grease really well, but you must rinse the surface to remove all of the residue.
Read More From Dengarden
Removing Fisheye Craters and Cleaning the Surface
The best way to stop fisheye is to remove the contaminant that's causing the problem. Never attempt to patch over the craters and re-paint. It doesn't work, and you will end up having to start all over again when the craters reappear.
The worst part of fixing a fisheye problem is the miserable task of having to remove the craters so the surface is smooth again. If you're lucky enough to have only a couple spots to fix, removal is easy. If you're dealing with widespread fisheye, the best course of action is to completely remove the paint and thoroughly clean and neutralize the entire surface before repainting.
The best way to remove the craters is to either sand them out, use stripper, or use the appropriate thinner. Sanding with coarse sandpaper is the easiest way to remove them if you're able to use a coarser grit that won't damage the type of wood you're working with, otherwise use a chemical stripper. Try sanding first before resorting to chemicals.
When I ran into problems spraying pre-catalyzed lacquer on cabinets, I removed the craters with a combination of lacquer thinner and sanding with 220-grit sandpaper on an orbital sander. I was able to remove all of the spots down to the wood.
Pay attention to what's below each crater as you remove them. Fisheye that forms only over wood knots means a contaminant or moisture is trapped inside the knots and cracks. Removing contamination from wood knots is very difficult, if not impossible. Further in the article, I cover a spraying technique you can use to solve the problem.
Cleaning the Surface
The best way to attack a fisheye problem is to first clean the surface really good after removing the craters and paint. A heavy duty cleaner like TSP, or Krud Kutter, will remove silicone, oil, wax and other contaminants. Scrub the surface with a coarse cleaning pad and carefully rinse with clean water. If you're using TSP, the surface must be rinsed thoroughly to get rid of the residue. If thorough cleaning doesn't work then you might have to resort to the next option.
Spray Several Light Mist Coats
I encountered fisheye once spraying cherry cabinets with pre-catalyzed lacquer and this was the only method that solved the problem. In my case, the contaminant, likely silicone, was trapped inside the wood knots because my customer had used furniture polish on the cabinets. The fisheye only occurred over the wood knots on the fronts of the doors, not the backs.
If you happen to be using a sprayer for your project, spray several light mist coats onto your substrate instead of only one or two heavier coats. The final coat after your mist coats will be your heavier coat. This method works by bridging over the contaminated areas with tiny atomized particles that are too small to fisheye. Each mist coat fills the area in more and more until you can eventually apply one final coat without any problems.
This simple method works great for lacquer fisheye, but it can work for paint too. I highly recommend trying this method if you've tried everything else unsuccessfully. This was the only strategy that got me through my fish-eye nightmare. Lightly scuff sand between mist coats to keep the finish smooth.
Try Fisheye Eliminator as a Last Resort
I would only consider using fisheye eliminator if all else fails. I would first try cleaning the surface and ruling out all other possibilities for contamination such as dirty spray lines, silicone from a furniture cleaner, wax from tack cloths, or oil in the blow gun for your air compressor.
Fisheye eliminator is a chemical additive that reduces surface tension to allow what you're spraying to flow evenly over the surface, but the problem is some contain silicone and other chemicals that contaminate your spray equipment. Another problem is spraying this stuff can also contaminate your work space for future projects.
If you resort to this option make sure you choose a product that's compatible with what you're spraying. When it comes to paint, fisheye eliminator is usually sold in home improvement stores, but it's harder to find locally for the lacquer that I work with.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Matt G.