There are so many primers on the market today. Its hard to know when to use the best one. Or when to use a primer at all. Now there is even Paint and Primer in One.
Why Use a Primer? – Simple. The primer allows for the top coat to dry like it was intended to. When the topcoat dries by the liquids soaking in to the surface, this pulls out the solvents in the wrong way and the paint dries too fast. Also the solvents that soak into the drywall typically damage the drywall. Primers meant for drywall don’t have solvents that mess with the drywall so much.
We split this topic into two sections. Different Types of Primers –and- Different Situations That Require a Primer.
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Different Types of Primers
- Bonding Primer – Bonding primer is great for problem areas such as chalky paint that did not totally power wash off. The only place you should NOT use a bonding primer is when the paint is already peeling. Good bonding primers dry in a way that they grab onto and tightly grip the surface. If the surface is already peeling the boding primer will tear the peeling paint off more. This phenomena will happen with ALL cross-linked primers or paint.
- Tintable Primer – Tint is certainly not the best thing for any primer. Adding tint to primer makes it dry slow and perform poorly as a primer. We always follow the recommendations for amount of colorant and cut that in half. Remember that any good primer will seal the surface so the tinted topcoat will sit on top instead of soaking in. Thus it will cover better. Often times a heavily tinted primer will need an extra coat when an un-tinted primer or slightly tinted primer would do a better job.
- Acrylic Primer – Acrylic primer is a very high quality primer and unfortunately will be priced the same. It will seal, fill in cracks, and bond very well. If you intend to use an acrylic primer remember that most very high quality primers will be acrylic primers. Previously mentioned bonding primer is acrylic.
- PVA Primer – Poly Vinyl Acetate – This is an excellent primer that you can use on fresh drywall and fresh mud, especially with an expensive topcoat that you want more coverage without spending more money. PVA is generally ONLY works great for sealing a surface and dries slick. It does however take small amounts of tint very well and causes much darker colors with less colorant. I would not use PVA on my bedroom or bathroom walls but I would for a non everyday use type of room like home office and guest rooms due to the loss in durability compared to a high quality acrylic primer.
- Alkyd Primer – Alkyd primer is best for water stains and ink stains. Alkyd primer is not a water based primer and wont clean up with water. Alkyd primers will block the hardest stains with a single coat. The major downfall to alkyd primer is that you will have a serious difficult time getting any type of smooth pretty finish over an alkyd primer
- BIN Primer – BIN Primer is a shellac based primer and is alcohol based. BIN is best for blocking smoke damage but will block anything but certain colors of magic marker. However the substrate MUST be totally dry of water moisture. Remember to have the guy at the counter shake this product twice! This primer will bond to anything but is thin and hard to work with. Often time the finish of the primer will also need to be lightly sanded. BIN primer will also leave a perfectly smooth finish for your topcoat to also be smooth.
- High Build Primer – (Undercoat) These are primers that are simply designed to fill in small cracks and holes. They are generally cheap per gallon but don’t go as far as a normal primer. One great example of a high build pime is Valspars high build primer. We apply it very thick and then pole sand the entire suface fo a beautiful finish.
- Paint and Primer in One – This is not truly a primer and should not be used as one. Most of these paints are simply thickened with a very cheap thickening agent. Please Read Here for more information on the topic.
Different Situations That Require a Primer –
- Water Stains – Water damage is best covered up by an Alkyd Primer. Try using this out of a spray can for best results. Apply with two or three very light coats so they dry more quickly.
- Patches – If there is a ton of patch work the best thing is to use a PVA Primer on the entire wall. Or if you just have a few spots try a few light coats with Alkyd Primer in a spray can. They also make BIN primer in a can for faster drying.
- New Drywall -The best primer for new drywall is an acrylic primer. This will seal the drywall so the solvents from the topcoat cannot penetrate and crack the drywall. If the drywall job was poorly done then one or even two coats of acrylic will do the job some justice.
- Smoke Damage – Smoke Damage is best covered with BIN Primer. Remember to have the guy at the counter shake this up twice. PVA and acrylic primers will also work but take at least two coats to stop the smoke damage from coming through.
- Chalky Areas – Any chalky areas will need to be power washed first using TSP. What doesn’t come off can be covered with an excellent acrylic primer. The acrylic primer will bond like glue.
- Hardy Board (Composite Wood) – This is a topic of little known facts. Most will tell you to use any primer you want. NOT TRUE. Most solvent even in water based paints will destroy the glue that holds the wood together! We only use one primer from our paint manufacture PPG Porter paints. A100 Primer. Then we go with a higher quality topcoat
- Extreme Color Change – For going from a dark or bright color use acrylic primer. Most color changes, even somewhat extreme, can be handled by a PVA primer.
- Galvanized Metals – Galvanized metal requires specialized primer usually water based.
- Bare Metals – There are many choices here. Generally they are all oil based with the exception of a few water based primers that are just OK for metal. If there is any risk of rust a rust prevention primer is necessary.
- Wood – Most paint manufactures make a good primer for wood. The primer should be high build so it fills in cracks. If you really need to seal it up good go with an oil based primer and be sure that the primer dries fully.
- Drastic Color Change – Drastic color changes can be made usually with two coats of high quality paint however darker to lighter sometimes is impossible without a primer. Lighter to darker is doable with extra coats because the colorant from lighter colors will not soak into a darker paint like darker colors will bleed into lighter colors.