
Polyurethane over lacquer sanding sealer. 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. Other varnishes such as polyurethane varnish dont gum up sandpaper so they sand easily without the need of a sanding sealer. Second polyurethane is not the best choice for painting over lacquer finishes.
Long story short yes use it. As it happens regular alkyd varnish and nitrocellulose lacquer gum up sandpaper when sanded. What is sanding sealer when do i use it how do i use it. I now know that not all sanding sealers are compatible with polyurethane finishes.
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. The stearates make sanding sealer rather soft. 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. 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.
Lower temperature higher humidity lack of air movement or application of thick coats will extend drying times. In any case use trivets. You might consider sanding off the lacquer and using industrial strength poly. A word of warning is in order.
I often have glass cut for side tables that see a lot of use since i find coasters a pita. 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. Adhesion is okay but not great and heat might compromise adhesion. Do not apply polyurethane or other varnishes over minwax lacquer sanding sealer.
In this video rebo explains the how and whys of using a sanding sealer. 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. 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. I am wondering if putting coats of polyurethane finish on the table top will add any durability.
That is the questions. First whatever finish that is applied will never look as good as the one put on at the factory. In this case applying a thin sealer coat of shellac which isnt affected by silicone separates the silicone contaminant from the topcoats.