I do not lacquer my models until I have finished completing all the paintwork.
Scamp

I take an immediate time out. Get the nearest piece of wood or plastic scrap that you have lying around that mimics your project and do a test or two to assure yourself of chemical compatibility.
As you can imagine, I am test obsessed. And remember to let lacquers gas out Before putting anything over them.
😉

It is best if you use the same type of paint. the solvents in all the paints have a tendency to out gas. you don't say what type of paint you are using for you 2nd coat. normally you never use solvent-based lacquer paints over enamels or acrylics it will blister. it is all based on the solvent in the paints. They all out gas differently and they dry (cure) differently. and the humity also affects the paints on how long between coats. there are water-based lacquers out there also. so do test samples. even then if some variable will cause an issue.

Be careful with lacquer. I am attaching a part of an article on this topic below, as it explains it better than I can:
(Bottom line, Lacquer can be "redisolved" by solvents from anything painted over it)


I'll add some input here. I'll kind of oversimplify but cover some basics. All finishes fall into one of two categories: Soluble or Insoluble. Soluble finishes dry by evaporation of the solvent that was used to make the paint thin enough to spray. Lacquers fall into this category.

The opposite of this is obviously the "insoluble" type of finish. Insoluble finishes are typically finishes that have been catalyzed with an isocyanate activator or hardener. The drying in this type of finish happens through a combination of evaporation of the solvent and a cross linking of the molecules. Once dry and fully cured they can no longer be redisolved and have very little ability to soak up a newly introduced solvent such as in a repaint. Enamels, Epoxies, and Urethanes are typical examples of insoluble finishes.

The problem with painting anything over a refinish lacquer (or soluble finish) is that they will forever absorb a solvent no matter how long ago it was painted. Whether it is the basemaker from a urethane paint, more lacquer paint or the solvents in a sealer, the soluble finish will soak up the solvent that is in whatever you are spraying on top of it. This causes the soluble paint to swell up as it absorbs the solvent. Problems may not show up initially but as these solvents once again evaporate back out, the soluble finish underneath the new repaint shrinks. Maybe a few months down the road, maybe a few weeks. You might see sandscratches, checking, crazing, etc.

After completing the undercoat and the first layer of colour if I then use a lacquer coat to protect it can I then mask the bottom of the keel and paint the second coat of colour over the lacquer or will it not bond ?