OK, all hot rodders have heard of “fish eye” or seen this paint flaw on more than one occasion. It’s also known as: silicone contamination, poor wetting, saucering, pits, craters, and cissing. (Most of these terms I’ve never heard of but they are used in the paint industry.)
The fish eye is a small, crater-like opening in the finish (topcoat or color) after it has been applied. It generally comes about because of improper or insufficient surface cleaning or preparation. Remember a few paragraphs before we made mention of using a polish that’s silicone free, now you know why. Many waxes and polishes contain silicone, the most common cause of fish eyes. Silicones adhere firmly to the paint film and require extra effort for their removal. Even small quantities in sanding, dust rags can cause this type of failure.
Another cause could be the leftover effects of a previous finish or an older repair. The previous finish or older repair may contain excessive amounts of silicone from additives used during their application. It’s been painters’ experiences that usually solvent wiping will not remove embedded silicone. Contamination is a big deal in painting and a contaminated air supply (water or oil), other oils, wax, grease, or silicone are the key points of emphasis when trying to avoid fish eye appearing in your new paint. Something to remember about silicone it can be found in polished but it can also be found in other aerosol sprays, such as interior cleaners or dressings and these should be kept away from any area that is used for painting.
It should be obvious what you need to do to prevent fish eye. Treat silicone as your enemy and keep it away from any and all areas to be used for painting. Make sure to properly clean the substrate to be painted and drain and clean air pressure regulators before any paint project is begun.
Should you find yourself with fish eye in your paint then you can apply light coats of basecoat until the defect is covered. There is also a fish-eye eliminator that can be used. If the fish eyes are severe then you will be required to sand the affected areas, clean thoroughly, and refinish.
Yep, here’s another all of us are familiar with and it is also known as: loss of adhesion, shelling, poor bond, delamination, flaking, and poor adhesion. It is the loss of adhesion between the paint and the substrate (steel or aluminum) and the topcoat to primer and/or previous finish, or primer to substrate.
Again, improper cleaning and/or preparation is one method that will ensure that your paintjob will fail. This can manifest itself by not removing all of the sanding dust or other contaminants as it will stop the finish coat from coming in contact with the substrate. Improper metal treatment by failing to use a metal conditioner and/or wash primer is another way, as would be the use of incompatible material for substrate. Improper mixing, failure to use the proper sealer, and paint film too thick are more poor methods that can lead to peeling. By applying material too dry, material was too dry when the masking tape was removed, flash times too short, poor sanding techniques, condensation on substrate resulting from temperature changes, or too low or too high of surface temperature when applying refinish.
To prevent peeling from occurring make sure to degrease and prepare substrate carefully, use the proper grits of sandpaper, seal to eliminate sandscratch swelling, proper thinner or reducer for your work environment, proper thinner and reducer for primer-surfacer, compatible paint systems, and do not apply coats of primer too heavily.
Should you already be in peeling hell then you will need to remove paint from an area slightly larger than the affected area and refinish.
Again, another paint aliment known to rodders is often referred to as: pinholes, solvent retents, pock marks, pitting, pops, and pin pricks. These are tiny holes or groups of holes in the finish, in putty, or primer, and are the result of trapped solvents, air or moisture, or improper surface preparation.
The most probable causes of pinholing are some of the same issues that cause any number of problems. For instance, improper surface cleaning or preparation; moisture left on primer-surfacers will pass through the wet topcoat to cause pinholing. Contamination of air lines, moisture or oil in air lines will enter paint while being applied and cause pinholes when released during the drying stage. Wrong gun adjustment or technique; too wet, or if the gun is held too close to the surface, pinholes will occur when the air or excessive solvent is released during drying. Wrong thinner or reducer; solvent that’s too fast for your garage temperature tends to make the refinisher spray too close to the surface in order to get adequate flow. When the solvent is too slow, it is trapped by subsequent topcoats. Improper drying; fanning (back to that again!) a newly applied finish can drive air into the surface or cause a skin to form, both of which result in pinholing when solvents retained in lower layers come to the surface. And a handful of lesser but equally troublesome poor techniques are insufficient sanding or filling of pores in fiberglass substrates, insufficient mixing of polyesters, solvent popping that has not been sanded to smooth, and insufficient isolation of polyesters.
Should you find yourself dealing with pinholes here are some ways out and these are all the same procedures you should have done with any number of other paint fixes. Thoroughly clean all areas to be painted and make sure surface is completely dry before applying undercoats or topcoats. Proper care and maintenance of air supply system and paint application equipment; also make sure you use the proper gun adjustments, techniques, and air pressure. Suitable thinner or reducer for your garage environment, allow proper flash time, and no fanning with compressed air through spray gun. Also, make sure to thoroughly mix polyesters, sand smooth the solvent pop pores and other defects.
Here’s what many of us would call the most common paint oops: runs. It’s also known as: overloading, curtains, gun spits, sags, sagging, and drips. But, let’s face it, all of us call by what it looks like—a run. Officially it is the heavy application of sprayed material that fails to adhere uniformly to the surface.
Runs can be caused by incorrect spray viscosity, improper flash time, poor technique, or film (paint) thickness. Runs can also be brought about by a defective spray gun or improper setup, too much or the wrong thinner or reducer, surface contamination or the paint area is too cold, and the obvious, paint drops directly from the gun!
To prevent these causes it’s better to allow vehicle surface to warm up to room temperature before applying paint, then maintain the proper room temperature, use a properly maintained gun with correct technique and air pressure. Make sure to allow for proper flash and drying time between coats and use the proper thinner and/or reducer, and proper equipment.
Ok, it’s too late and there’s a run, how do you remedy this problem? Begin by washing off the affected area and let dry until you can sand to a smooth surface and then refinish. For solid colors and clearcoats, sanding and polishing is recommended. In the case of a basecoat, refinishing after sanding is necessary.