08-24-2010, 11:41 AM
08-24-2010, 12:13 PM
Prekote already has filler materials in it. If you add more you run the risk of decreasing it's adhesion properties. Unlike epoxy and other thermolidic polymers, you can't saturate this primer. By the time the vehicle evaporates, you've lost a fair percentage of the primer bulk. Adding fillers will decrease the vehicle/resin and resin/pigment ratios. This effectively dilutes the primer, making for a weak bond with the substrate.
This is why the advice is always multiple thin coats, rather then fewer, thick coats. Several thin coats applies a higher percentage of filler material on the substrate.
If you have substantial defects to fill, you can isolate them, mask around them and treat them separately, which will save primer and surround areas the extra effort. In other words, go around the hull, mark the areas that need more filler and apply several coats of primer on each. Once dry, remove the masking and "block" these areas down to the surrounding areas and see if the imperfections are gone. If not, you have no choice, but to go back and apply a real filler, then prime and block the area again. As a rule, primer doesn't fill very deep imperfections.
This is why the advice is always multiple thin coats, rather then fewer, thick coats. Several thin coats applies a higher percentage of filler material on the substrate.
If you have substantial defects to fill, you can isolate them, mask around them and treat them separately, which will save primer and surround areas the extra effort. In other words, go around the hull, mark the areas that need more filler and apply several coats of primer on each. Once dry, remove the masking and "block" these areas down to the surrounding areas and see if the imperfections are gone. If not, you have no choice, but to go back and apply a real filler, then prime and block the area again. As a rule, primer doesn't fill very deep imperfections.
08-24-2010, 12:29 PM
Thanks, Paul. Great answer. I'll do as you recommend.
Dave
Dave