I like to do at least two coats of primer, and I strongly recommend you do two coats of primer for laminate kitchen cabinets (or bathroom cabinets) where you're going to subject them to everyday use.
Depending on what kind of primer you're using and the state of the cabinets, you will need 1-2 coats of primer. For many cabinets, one coat is plenty, but if you're uncertain, a second coat won't hurt as long as it's not applied too thick. When it comes to the actual paint, you will need at least two coats.
For painting laminate furniture, you want to do at least 2 coats of primer and let them cure completely (overnight if you can!) in between coats. You can even sand in between coats for maximum adhesion.
Step three: Prime
Priming is really important with laminate furniture, so don't jump straight to applying the paint as this will be wasted effort. If the laminate has never been painted before, you will need to apply two coats of primer.
But really, the best results will come from pre-sanding your laminate cabinets thoroughly to prepare them for painting. By scuffing up the surface of the laminate, you give the primer a better, more adhesive surface to bond to.
Our cabinets have a laminate finish which means that they're really smooth and getting paint to adhere to them can be tricky. The secret to achieving a long-lasting finish is sanding and using the right primer.
By using a primer, you essentially block that layer and give your paint a fresh canvas to adhere to. Second, it is also a good idea to prime your laminate furniture piece before painting ESPECIALLY if you are going from a dark color to a lighter one.
You will want to use 2-3 coats of primer to ensure there is a good bond between the new paint and the wall, and also to cover up any previous colors, especially if they are red, orange, or a strange outdated color. In short, you will typically need 2 coats of primer for most painting projects.
If you're painting wood without a stain or finish, use a latex or an oil-based primer for the best results. Don't over or under apply the primer: You should aim to apply two coats of primer to your wood's surface. Brush the primer on, and allow the first coat to dry completely before adding the second coat.
On a new wall, you'll want to follow the rule and apply two coats of paint after primer. Follow the same standard for drywall. If you're repainting a wall, you'll only need one coat if you're using the same color and it's a quality paint.
You may never need three coats of primer, but there are situations in which a third coat is necessary. If the second coat of primer hasn't offered the coverage you're after, go for a third coat before applying your final paint.
Too much primer causes a different set of problems. Too many layers or an excessively thick layer increases the risk of the primer cracking, crazing, or chipping. It also takes longer to dry, slowing down your redecorating work. In the worst case scenario, it can damage drywall by causing it to bubble and peel.
Applying the second coat too early will result in lost time, money, and effort. Not only that but it'll also create additional stress that's not necessary. Applying the second coat too early will result in streaks, peeling paint, and uneven color.
You certainly don't want to skimp on the number of coatings you apply to your cabinets, but you also don't want to go overboard. Slapping on too many coats of primer or paint during cabinet refinishing can hinder adherence, interfere with proper drying, and result in strange lines and patterns on the finished surface.
Depending on how strong or bold the previous color is, it may be necessary to apply more than one coat of primer. However, it is not necessary to over apply the primer with so many coats. As long as the primer applies uniformly over the previous color, then one or two coats should be sufficient.
Note: While you don't have to sand before you prime, you do need to sand lightly after you prime and between each coat of paint.
Due to the way MDF is made, exposed edges tend to absorb paint much more than the surface, so you will need to apply an extra coat or two of water-based primer on the edges. Preparation tape stops the paint from being absorbed by the MDF and acts as a primer, saving you time and effort.
A good rule of thumb is to wait at least three hours to recoat your paint or primer if it's water-based. Waiting 24 hours is best for oil-based paint and primer. If you're unsure, the instructions on the paint's label can give you the best final say.
Summary. For your finish to be vibrant and not dull sanding after primer will ensure that the finish is not excessively dulled when you apply your paint top coat. You will typically use finer grit sandpaper and aim to achieve a smooth wood finish so that you get a fine appearing wood finish when you apply your topcoat.
MDF is quite an absorbent material and typically you will need to apply at least two coats of primer. You may need to apply a third, especially on the edges. After the second coat, rub down lightly with a fine-grade sandpaper -180 grit will do. Make a judgment call on whether you need a third coat or not.
The primer coat doesn't have to be perfect, but it should cover the surface (no bare spots) and it shouldn't be so blotchy that you get drips or visible unevenness.
Full primer coats at a minimum of 75 μm overall, plus an intermediate coat and topcoat, to a minimum total dry film thickness of 190 μm.
BIN Shellac Based Primer
But, you won't have to concern yourself with tannins on your laminate furniture since it's not actually real wood and all. BIN Shellac Based Primer also has excellent adhesion and sticks to slick surfaces such as glass, ceramic tile, plastic, metal, and hardboard.
Primer is important, especially when painting over laminate. Unlike wood, laminate is a smooth, non-porous material, so it really needs something to 'grab' onto—primer will do the trick! It's suggested that primer takes seven days to completely dry.