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  #1  
Old 05-26-2009, 04:36 PM
spifflog spifflog is offline
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Do I really need to prime before I paint?

Is there any reason that I should prime my interior walls? I know that "they" say that I have to use a primer. But if I'm putting two coats on, why to I need three?

Is it possible that with new and presumably better paint, that priming is antiquated?
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  #2  
Old 05-26-2009, 04:40 PM
keeper0 keeper0 is offline
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I asked that question before the wife and I painted many rooms in the house.

Two answers which resulted in us using primer were:
- primer has better bonding agents which allow it to stick to old, dusty walls. (I know you wipe them down, but you don't get everything off)
- primer is cheaper than paint, so if you do a coat of tinted primer instead of a coat of paint, you save money.

The validity of those comments can likely be debated.
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  #3  
Old 05-26-2009, 04:50 PM
billfish678 billfish678 is offline
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priming REALLY helps the new paint go on smoother. IFF you have a high quality topcoat and are good at painting and prime to boot, you can get by with one topcoat application.

In practice, you still might as well do 2 topcoats. But they will be easier coats that look good and mostly make up for the extra work that was required to put the primer on.

As mentioned, it really does help the topcoat go on smoother and more importantly STICK.

You do NOT want the living hell that a peeling paint job presents. I get all stabby just thinking about it. It will most likely peel enough to be a disaster, but not enough to actually be peely enough to be remotely easy to peel off and redo.

think of it as insurance.

Also, it never hurts to give the walls and trim a good cleaning and prepping. You think you can paint over grim, or holes, or bumps, or dust and dirt, or any other imperfections, but IME it will most likely look like you painted over them rather than the new paint actually hidding them.
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  #4  
Old 05-26-2009, 05:55 PM
salinqmind salinqmind is offline
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I painted my bathroom just this weekend and used primer, you betcha, a couple of days before the paint. Didn't bother with primer in this high humidity area a couple years ago and the latex paint was curling up right off the wallboard, a disgusting sight. I had to scrape and scrape and sand some parts before the primer. (The cat helped, he's a chewer and pulled off some long strips near the floor without being asked!) I didn't use primer first on the other walls of the house, and the paint has stayed on fine.
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  #5  
Old 05-26-2009, 06:32 PM
nivlac nivlac is offline
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If you're painting over new sheetrock, definitely use a primer coat! If you're painting over old paint, clean the old coat as much as possible and paint away with the new paint.
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  #6  
Old 05-26-2009, 06:47 PM
sailor sailor is offline
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I have found some things absorb paint like crazy and unless you prime first you end up having to give many coats and use a lot of paint. In that case priming saves work, paint and money.

In some cases you have stains on the wall and they come right through the new coat of paint. A primer will cover them and will seal the wall so that stains do not come through.
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  #7  
Old 05-26-2009, 11:09 PM
Liberal Liberal is offline
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Yes. You really need to prime before you paint.
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  #8  
Old 05-27-2009, 09:07 AM
crazyjoe crazyjoe is offline
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It really depends. If you have stains, or will be spackling, then primer will go a long way toward sealing that up so that stains do not bleed through and the spackle doesn't absorb too much of your paint, making the spackled areas obvious. Also, if you are painting a lighter color over a darker color, primer will help immensely. It is thicker and seals the dark color out much more easily. You would need 3 coats of expensive paint to cover a dark color sometimes, as opposed to 1 coat of much cheaper primer.

If you have a nice looking wall surface that just needs fresh paint, a good cleaning and new paint is all you really need.

Last edited by crazyjoe; 05-27-2009 at 09:08 AM..
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  #9  
Old 05-27-2009, 11:51 AM
Claire Beauchamp Claire Beauchamp is offline
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Quote:
Originally Posted by crazyjoe View Post
If you have a nice looking wall surface that just needs fresh paint, a good cleaning and new paint is all you really need.
I will add that if you're tempted to skip primer, DON'T if you were not the person who put down the most recent coat of paint and don't know what kind of paint it is. Oil paints aren't that common any more, but if you put latex on oil it will not stick without a primer.
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  #10  
Old 05-27-2009, 11:59 AM
Jodi Jodi is offline
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Originally Posted by Claire Beauchamp View Post
I will add that if you're tempted to skip primer, DON'T if you were not the person who put down the most recent coat of paint and don't know what kind of paint it is. Oil paints aren't that common any more, but if you put latex on oil it will not stick without a primer.
Thanks for this. I'm getting ready to paint my new (to me, actually old) house interior and I've never bothered with primer in the past unless painting over a dark color. I'll prime this time!
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  #11  
Old 05-27-2009, 05:15 PM
WPA-Guy WPA-Guy is offline
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After 10 years in the Hechinger (r.i.p.) paint department, here are a few other things to keep in mind about priming and painting.

1. Some builders use a grade of paint that has a lot of clay in it. It sprays easily, and covers up marks on the wall well. But when the next guy paints over it, the clay sucks up the paint. I'd rather use the $10 primer to seal up the old coat than have to use three coats of $25 a gallon paint.

2. All purpose primer does not seal water stains or sap stains from wood. If you have these type of stains, use a primer/sealer like Kilz or BIN, or seal the stain with shellac.

3. If you are trying to paint over a layer of oil-based glossy paint with latex paint, you will need something called liquid sandpaper to bond the paint layers. I've seen sheets of latex paint pulled off of doors that had been previously painted with oil-based paint.

4. The rule of thumb is you will spend at least as much time on preparation as you will painting.

Last edited by WPA-Guy; 05-27-2009 at 05:16 PM..
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  #12  
Old 05-27-2009, 07:49 PM
Really Not All That Bright Really Not All That Bright is online now
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Oh dear.
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  #13  
Old 05-27-2009, 07:56 PM
bink bink is offline
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Oh, go ahead and prime. It makes painting so much more pleasant. You cover the whole room, walls, trim, doors and all, with a coat of prime and everything is nice and white. This lets you see where you need to do more surface prep or gap filling. Then when you go to paint there's a nice flat, almost chalky, finish to everything and the paint goes on really nicely.

I never used to prime but I'm a convert now.
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  #14  
Old 05-27-2009, 08:41 PM
WhyNot WhyNot is online now
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OK: stupid question. If primer is cheaper, sticks better and hides stuff better, why don't they just put the dyes in the primer and call it "really good paint"?
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  #15  
Old 05-27-2009, 08:47 PM
Rumor_Watkins Rumor_Watkins is offline
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Originally Posted by WhyNot View Post
OK: stupid question. If primer is cheaper, sticks better and hides stuff better, why don't they just put the dyes in the primer and call it "really good paint"?
It's kinda dull, not very appealing as a finished look.
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  #16  
Old 05-27-2009, 09:39 PM
Chief Pedant Chief Pedant is offline
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Originally Posted by spifflog View Post
Is there any reason that I should prime my interior walls? I know that "they" say that I have to use a primer. But if I'm putting two coats on, why to I need three?

Is it possible that with new and presumably better paint, that priming is antiquated?
The thing to remember is that primer is paint, but with its properties tuned to filling and binding rather than a final finish.

As a rule of thumb, the more porous the surface, the better off you are with a primer. Primers are usually, but not always, cheaper. Some primers are also made specifically to cover water soluble stains which will otherwise constantly bleed through a latex surface because the water-based latex solublizes the underlying discoloration and lets it bleed through.

Say you are painting a bathroom, newly drywalled. You can get by with an inexpensive primer to seal and prepare a very porous surface. But your finish paint is going to be a semi-gloss (at least) for moisture resistance. You would get poor results with no primer, and expensive results with two coats of your finish paint. It will be much easier to blend the finish paint strokes over a primed surface than if the surface has not been primed.

Say you are re-coloring a metal surface with a good enamel finish already on it. Primer is a waste of time.
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  #17  
Old 05-28-2009, 02:32 PM
MonkeyMensch MonkeyMensch is offline
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Quote:
Originally Posted by WhyNot View Post
OK: stupid question. If primer is cheaper, sticks better and hides stuff better, why don't they just put the dyes in the primer and call it "really good paint"?
Ex-pro checking in: Not a stupid question at all. Keeper mentioned it in the second post: you CAN tint it but you don't want to use it as a finish coat. It comes out with a dead-flat finish, a really dead flat finish. But this finish is exactly what you want in a primer. Most of the bond in latex paints is mechanical, that is to say, it holds on the the microscopic roughness of the previous coat.

I recently painted my sister's living room room from a pale aqua to a deep burgundy. So after repairs, cleaning and sanding I put on a coat of primer nearly as dark as the finish color. Thus prepped I only had to hang one finish coat and be done.

Two things:
1. As has been alluded to, if you don't know what the finish coat on which you're about to paint is you have to prime. Really.

2. Buy a extensible paint pole for rolling out the room. I cracks me up on the home improvement show to see them with the roller handles in their hands, bending over EVERY time to reload. They must dig sore backs!
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  #18  
Old 06-01-2009, 02:31 PM
crazyjoe crazyjoe is offline
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Painted the little one's room this weekend, and discovered that the people who painted before us didn't use primer..or they did somethign horribly wrong, in any case. Trying to sand high spots and remove globs, paint came off in sheets 3 layers thick (3 color layers, lord knows how many actual coats). I finally gave up trying to peel it all off, and just sanded down a good bit of it and primered everything....he's only 2, and I imagine he'll want the color changed again soon enough, so we'll do everythign the "right" way next time.

(and I won't listen to my wife about not using a power sander....dust is dust, if there's an inch of it or a foot, it's going to spread, so we'll ventillate well and I will be bringing out the power sander.)

Last edited by crazyjoe; 06-01-2009 at 02:32 PM..
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