I'd like to offer a few tips for DIY painters and when to use primers. I think priming is one of the most misunderstood aspects of painting and maybe this can help settle some of the confusion. I am by no means an expert but I do think I know what I'm talking about. If anyone has some counter points or other tips, please discuss and we can help each other.
In general primers have 2 main functions: promoting adhesion and sealing / stain blocking. Most people think primers are used to cover dark colours when painting light colours. I'll get back to that.
My rule of thumb is to prime anything that hasn't been painted before. Drywall, wood, metal, plastic, etc.
I never use Home depot paint products but I know most people do, I'll post the related home depot products. Also, when going to home depot or lowes, etc, be careful about the information they tell you. They often aren't trained properly.
drywall primer - This is the cheapest of all the primers. I'll use it to prime over new drywall that has been taped and sanded. This primer will seal in the plaster and help you get even coverage with the topcoat. These are sometimes called PVA primers.
Kilz Pro-x http://goo.gl/iOhHt8 and Behr Premius Plus drywall primer & sealer are two options http://goo.gl/I5NhUw
wood primer - bare wood should be primed with a general purpose primer. I have used the PVA to prime poplar trim and it does work, but a primer designed for wood will make the job a little easier. Wood grain tends to rise when its contacted with latex paint. Wood primers will lessen that effect and require less sanding afterwards.
Behr all in one primer http://goo.gl/cz2VGX
adhesion promoters - These primers are more expensive. I'll use these to prime bare metal, plastic, oil paint, varnished wood, melamine, etc. Make sure you scuff glossy surfaces. This will help adhesion as well. If you have an older house your walls might be painted in oil. This is also where you would have to prime your walls. To test if your walls are painted in oil, rub a cotton ball soaked with acetone on the walls. If the paint comes off on the cotton ball, it's latex. If it doesn't come off, it's oil.
Zinsser 123 http://goo.gl/zmI5BG
stain blocking primers - certain stains will come through latex paint no matter how many coats there are. These include cigarette smoke, water stains, grease, knots in wood, crayon, etc. Generally you'd have to use oil based paints to cover stains but there are some that will be covered with latex. For example, Kilz Max claims they cover water stains, but it takes multiple coats. It should take one coat with an oil or shellac primer.
Zinsser cover stain http://goo.gl/bOnxIm in oil or Zinsser Bin http://goo.gl/yXIs7h for tougher stains
exterior primer - These are generally used for exterior projects such as priming wooden windows, doors, masonry, shutters etc. Exterior paints are more elastic than interior paints and can handle adverse weather conditions
Behr exterior primer http://goo.gl/5tu8p1
OK so covering up dark colours with light colours. Here's my opinion on this. Primers don't have a lot of pigment in them. They're very watery. This means they won't do a great job covering up old colours. It's probably more effective to spend more money on the paint than to get cheap paint and cheap primer and try to do things in less than 3 coats. I did an experiment with a few different primers, trying to cover a dusty rose with a yellowish off white. I painted vertical stripes, overlapping each one just a bit until I couldn't see the pink underneath. It's hard to see from this image, but the winner was the top row which didn't have primer at all. http://ift.tt/1NbSQT5 Primers aren't more effective at covering up dark colours than paint. HOWEVER, primers are cheaper than paint. So say you know for sure you're going to need 3+ coats to cover. Do the first coats in a TINTED primer, leaving the final 2 coats for the paint. It's better to do 1 coat of $20 primer and 2 coats of $40 paint than 3 coats of $40 paint. Always do 2 coats of paint, no matter what.
One final thing: for the love of god, don't put semi gloss on your walls. It looks horrible and it's not necessary. Again, don't listen to home depot. Just get good eggshell paint and don't worry about it.
TLDR - prime previously unpainted surfaces
Submitted October 30, 2015 at 06:53AM by belardi http://ift.tt/1M0s4bZ
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