Proper Primer Selection
Posted May 31st 2014 | By:
Deciding what type of primer to use and when can be a complicated process. Different jobs call for different preparations, and using the right primer for the task at hand is essential to getting a long lasting result that looks good. Since primers are specially formulated, you will need one that bonds well with the surface on which you intend to use it, and evaluation of this beforehand should be part of your preparations.
Photo: Paint Pro
Primer is an important part of paint projects because of the benefits it offers. First of all, primers will seal surfaces such as wood, making them impermeable to things like damaging moisture. Secondly, primer prepares surfaces for painting not only by giving you a surface that will easily adhere to paint but will also be smooth and uniform, enhancing the appearance of the paint you apply. All unfinished surfaces should be primed before painting in order to prevent cracking, peeling, and bubbling as well as to give you a long lasting, attractive finish.
Photo: Pick Up Some Creativity
There are three main types of primer on the market today:
1. Shellac primers are great for handling stains and stopping bleed through of tannins when it comes to woods such as redwood or cedar, but they have strong odors and can be tough to use. The best uses for this type of primer include metal, plaster, wood, or plastic that needs to be primed for quick drying. Shellac primers are also good on surfaces with stains, such as rust, that you wish to hide and cover. When it comes to the thinning and cleanup of shellac primers, denatured alcohol is required.
2. Oil primers are best for tasks such as filling in surface pores and keeping tannins from bleeding through. Oil primer is ideal for use on unfinished or previously varnished woods that may even be heavily weathered as well as over paint that is cracking. However, do keep in mind that it dries slowly and releases VOC's (volatile organic compounds) in the process. Thinning and cleanup require mineral spirits which can be messy but the effort is worthwhile for the smooth finish offered by oil primers.
3. Latex primers are much more supple when dry than other primers and as a result, tannin bleed through or raised grains may be possible. Latex should be used on surfaces such as bare softwoods (like pine, for example), unfinished drywall, galvanized metal, concrete, or brick. Latex primer dries fast and creates a barrier that still allows the passage of water vapor which aids against peeling. This type of primer can also be purchased with low or no VOC's. Since latex primer is water soluble, cleanup is easy and requires only water to complete.
Photo of tannin bleed: I'm Busy Procrastinating
Once you've decided on the type of primer your project requires by matching the qualities of the primer to the task you intend to complete, don't forget to clean materials thoroughly before you begin the priming process. The surfaces you plan to prime need to not only be clean but also have been allowed ample time to dry; a gentle sanding ahead of time is useful as well. With you primer applied and dried, be sure to paint within a week to ensure an aesthetically pleasing job well done.
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