Though you can prime before or after caulking, under normal circumstances, priming first yields better results. Before beginning a do-it-yourself painting project, learn the proper preparation procedures, or you may end up making the job harder than necessary. Work efficiently by following each step in the proper order, or you may need to repeat it.
Under normal circumstances, you can apply caulk before priming; however, if you're working on certain surfaces, the caulk will not stick without a primer base coat. Caulk adheres very well to clean, bare wood and vinyl. Unfortunately, it will not stick well to stained surfaces. If you are working on finished wood, do not apply caulk until after you've primed.
Though you may apply caulk to bare, unfinished surfaces prior to priming, it is not the most efficient way to work. Even professionals are likely to overlook cracks, gaps and fissures when they apply caulk first. A base coat of primer helps these flaws stand out so they are easier to identify. If you caulk before priming, you're likely to notice skipped areas once you apply primer and will then have to go back and caulk a second time.
If you use a bright white caulk on your project, it may show through dark colors of paint. To combat this, you can add the primer after caulking. This will help with coverage and prevent bleed through. If you'd like to prime first, you can use a tinted, gray caulk that won't bleed through the finish coat.
One of the most common errors amateur painters make is to apply the wrong type of caulk. Acrylic caulk is the only choice for painting projects because of its good adhesive qualities. Clear silicone caulk is never appropriate for surfaces that will be painted. If you use a clear silicone caulk, the primer and paint will bond poorly and ultimately flake away.