Polyurethane Over Lacquer Sanding Sealer

Can i apply polyurethane finish over a lacquer finish if i use zinsser sanding sealer i have stripped stained and sprayed on 2 coats of gemini pre cat lacquer to a walnut dining set and buffet.

Polyurethane over lacquer sanding sealer. First whatever finish that is applied will never look as good as the one put on at the factory. Above dry times are based on good ventilation temperature of 770 f and 50 relative humidity. If you put a hard brittle finish like lacquer over a thick soft one like sanding sealer it is much more likely to chip and crack. Other varnishes such as polyurethane varnish dont gum up sandpaper so they sand easily without the need of a sanding sealer.

The stearates make sanding sealer rather soft. For example when refinishing furniture with lacquer or polyurethane silicone on the surface can cause the new finish to pull away from the contaminated spotsa condition called fisheye. In any case use trivets. From now on i will not use a sanding sealer at all as it is a unecessary step.

A word of warning is in order. As it happens regular alkyd varnish and nitrocellulose lacquer gum up sandpaper when sanded. Lower temperature higher humidity lack of air movement or application of thick coats will extend drying times. Finishing applying a sanding sealer to your raw project is a great way to seal the surface and allow your final topcoats to lay on the wood much smoother and with finer luster.

Second polyurethane is not the best choice for painting over lacquer finishes. I often have glass cut for side tables that see a lot of use since i find coasters a pita. I now know that not all sanding sealers are compatible with polyurethane finishes. In fact sanding sealer will hinder the bond of polyurethane so you shouldnt use it.

Polyurethane will not bond or grip well with the lacquer and will peel off over time with general use. You can put oil based poly over lacquer if you lightly sand first. That is the questions. In this video rebo explains the how and whys of using a sanding sealer.

What is sanding sealer when do i use it how do i use it. Adhesion is okay but not great and heat might compromise adhesion. Long story short yes use it. There are several things to keep in mind before moving forward.

I am wondering if putting coats of polyurethane finish on the table top will add any durability. For that reason if you use sanding sealer stick to one or two coats at the most and plan to sand most of it back off. Problems with polyurethane over sanding sealer the problem is the urethane based products are flaking slightly when sanded or will peal off if tape is applied.