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To Prime or Not to Prime

May 5, 2017 / Tips

If you’re thinking of doing a few do-it-yourself projects this year there are a few things to know. There is a lot of conflicting information out there so we have decided to give you a few do’s and don’ts for what to paint and how to paint it. This article will tell you everything about when you should prime and what to look for.

Oil paint is one of the most common problems we run into today. With changes in regulations, it’s impossible to paint oil over oil as there really isn’t any readily available. The problem is that most acrylic paint does not adhere to oil. So how do you know if you have oil paint and if you do, does it need a primer or is there another way?

First of all, checking for oil paint is pretty easy. While oil does have the feeling of glass compared to the slight texture of acrylic this can be hard to tell unless you have spent a lot of time around it. A simple test is to buy some acetone and rub it on the area, if paint comes off that means it’s latex if not it’s oil.

If it’s latex you can paint as normal, no additional steps are needed.

If it’s oil, the next thing is to determine what type of product to use in order to get a properly applied coating. The most fool proof solution is to prime with an oil primer, this will work every time and with little to no effort or worry. It does smell pretty terrible though.

An old oil coating sometimes doesn’t need special paints or primers. The problem with oil is there isn’t much for the acrylic to stick to but as it ages it becomes rougher and more porous. If you have old oil take the paint you want to use, dab it on a few different places on the surface and let it dry. Give it a scratch, if it peels you will have to prime or buy different paint. If not, you are good to go.

Another option is a hybrid paint like Emerald from Sherwin Williams or Advance by Benjamin Moore. While these paints offer superior adhesion they are still acrylic and can sometimes fail. We would recommend lightly sanding the area and putting a few dabs of paint in different areas. Once dried give it a scratch. If it peels, it is not adhering and if it doesn’t peel, you are good to go without a primer.

Always make sure your surface is clean and free of contaminants.

Primer can be used in many applications but is not needed in most, as you may be told. So when should you use primer?

When painting bare wood it is always a good idea to use primer. The reason for this is not primarily for adhesion but also for consistency. If you have cedar or other wood known for its contaminants you should always use primer.  If you don’t use a primer the contaminants will leak out of the wood and appear as “dirty spots,” the primer prevents this from happening. While there are a lot of paints that now are paint and primer in one, we find that whites and off whites always need a thick primer coat before painting to prevent the appearance of these spots. Also if you are replacing some pieces of siding and want to have a similar finish, a thick primer can help “fill in” the wood to give it a more consistent appearance.

When painting bare drywall it isn’t necessary to use a primer but you must always do a “primer” coat. When priming bare drywall you are doing so to let the paint or primer absorb into the drywall and therefore create a consistent coating on the following two coats. It is not necessary for adhesion and if you are using a good quality paint after three coats (primer + 2 coats) you should have a consistent coating. There is no need to use a paint and primer in one as they are more costly and do not affect the final look. Unless you are using vibrant or very dark colours.

Let’s Talk Vibrant Colours. A primer is recommended for vibrant colours as it helps a lot with coverage. Colours that are prone to a lot of coats of paint are reds and yellows. A grey base coat can take out a few steps while painting. The amount of colourants that are needed to create these colours take away from coverage. If you start with a gray primer in most cases you will cut down the amount of coats needed from 4 + to a primer coat and two coats of the colour being used.

Big colour change?  A primer can help while making a big change. The most extreme example is from black to white or vise versa. Use a grey primer when going from very light to dark and a white primer to go from dark to light. This also helps cut down on the amount of coats needed for consistent coverage.

Then there are water stains and other random stains. It is always best to use a stain covering primer like Zinzzer Cover Stain in order to make sure that it doesn’t show through. This product works great every time but does have an odor as it is also an oil primer.

Metals, vinyl and cement need different products.  Various types of paint can be used with or without primer in order to create a properly applied coating. It is always good to ask the paint store what products they have that can be directly applied to each of these coatings. With the right primer, you can use any type of paint on top depending on what you want the final look to be.

All in all and in most cases, a primer is not used for adhesion but to make a job easier or give the surface a certain look. A primer is only used to prevent failing when used on metal, vinyl, cement and oil paint.

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