Please Help: Painting Trouble

I desperately need some help. Here is the situation: I am trying to paint a wooden dresser, my plan was to prime, paint, glaze, and finish with polyurethane.

I started with a coat of Valspar Multi-Purpose Latex Primer. It was advertised as not needing sanding before application. Let that dry overnight.

Applied one coat of blue latex Olympic paint, let dry overnight. Coverage was not great, so I applied a second coat of blue latex paint and let that dry overnight as well.

Applied Valspar Tintable Latex Glaze to most surfaces. During this step, I noticed a hair (thanks, dog) in the paint. I tried to carefully pull it off, but it had stuck to the paint, which proceeded to begin to peel off the primer. I tried to use a razor to cleanly removed the damaged paint section, but it only stretched the paint more.

I ended up having to peel ALL of the paint off, which came off mostly cleanly from the primer. The primer was definitely bonded to the wood, but seemed not to be bonded to the paint AT ALL. The parts I hadn't glazed yet, i.e., that were drier, were harder to scrape, but once the paint was very lightly moistened with a wet rag, again, peeled right off the primer (like a layer of skin).

Where did I go wrong? It seems as though the primer failed to adhere the paint, but I'm not sure. I am extremely discouraged and frustrated after money spent and days' work invested and don't want to repeat any mistakes as I attempt this again in a few days.

Thanks for any advice.

 

Note, the latex paint was a flat finish.

 

The only thing that makes any sense here, and could potentially explain what's happening, is when you said that the dryer paint was harder to remove... until you got it wet.

You should be aware that latex paint is a slurry. Hard clear plastic blobs called "resins" are suspended along with clear, white and/or coloured pigments in a solution of water and a water soluble solvent called a "coalescing agent". All latex paints are composed of this kind of slurry.

The clear plastic blobs fuse together during the film forming process to produce a clear plastic film in which the pigments are suspended very much like raisins in raisin bread.

The clear plastic blobs are made from one of three different kinds of plastic:

1. Top quality paints and all exterior latex paints will have plastic blobs made from a plastic called "polymethyl methacrylate" which you probably know better by the name "Plexiglas". In the paint industry, this kind of plastic blob is called a "100% Acrylic" resin.
2. Budget priced paints and general purpose latex primers will contain plastic blobs made from a plastic called "polyvinyl acetate" which you probably know better as white wood glue. In the paint industry, this kind of plastic blob is called a "vinyl acrylic" resin.
3. About 5 percent of the latex paints out there will be made with plastic blobs made from "styrenated acrylic" plastic resins.

Now, the peculiarity of vinyl acrylic resins is that they both lose their hardness and their adhesion when they get wet. This is why you often see paint peeling on the ceiling above a shower in a bathroom. It's not that the paint wasn't applied properly or the prep work wasn't good enough; it's because the budget paint that was used to paint that bathroom ceiling simply doesn't have good resistance to moisture.

I'd look on the can of blue paint you used and see if it says it contains "vinyl acrylic" resins. If so, it's a good thing that you stripped it off your furniture. That's because one of the other peculiarities of vinyl acrylic resins is that they remain slightly sticky even when the paint is fully dry. This is why if you have your head resting against a wall for any length of time, you'll find that your hair sticks to the wall.

EVERY top-of-the-line latex paint will be made with Plexiglas plastic. Not only do Plexiglas resins adhere better to most surfaces than vinyl acrylic resins, they don't lose their hardness and adhesion when exposed to moisture, and they dry without retaining any stickiness at all.

I can't say for sure what happened that your paint didn't stick to your primer. But, if you repaint with anyone's top quality paint, you'll be using a paint that won't soften and lose it's adhesion when wet.

 

Thanks for the informative response! I checked the paint I have, and it has "vinyl acetate ethylene copolymer". Does this fall under the "vinyl acrylic resins" classification?

If I do upgrade to a better paint with polymethyl methacrylate, should I sand off the primer that's still on the wood, or just smooth it out and apply a new layer of primer, then paint with the better paint?

Thanks again!

 

I'd sand the primer and see how it looks, generally you don't need a 2nd coat of primer. I agree that a better grade of paint would be in order. I seldom buy/use paint from a big box, you'll find better coatings at your local paint store providing you get their mid grade or better.

 

Thanks so much. I go to my local store to get a better quality paint and try again. Wish me luck!

 

If they blue paint peeled off cleanly, then I don't see any need to reprime.

Primer is normally covered by paint so it doesn't have to stand up to UV light from the Sun or resist mold or mildew or stand up to rain or moisture in the air. Consequently, when picking a resin to make a latex primer with, good adhesion to the normal substrates primers get applied to in construction is about the only important consideration. Consequently, primers will generally have better adhesion to any given substrate than a paint will. Primers work to increase paint adhesion because they contain huge rocks almost large enough to see with the naked eye. These rocks (called "extender pigments") make the primer dry to a rough surface. It's the roughtness of that surface that increases the surface area of the primer. The paint doesn't stick to each square inch of primer any better because the surface is rough, but since the number of square inches is larger with a rough primer than with a hypothetical smooth primer, the apparant adhesion of paint to a rough primer is higher. That is, more square inches with the same adhesive force per square inch makes for better adhesion of the paint to the primer.

So, based on the above, the way you would tell if the primer is still good or not is a) whether it's still sticking well to the substrate, and b) whether it still has a dead flat gloss to it. If it's sticking well and rough, then you don't need to apply another coat of primer before repainting.

Hope this helps.

 

Stained Glass Dol:

Yes, a polymer is any plastic made of repeating units of the same chemical. Polyethylene, for example is a whole bunch of ethane molecules connected end to end.

A co-polymer is any plastic made of two or more different kinds of repeating units. So, the blue paint you used the first time would have had plastic resins in it where the plastic was fundmentally polyvinyl acetate, but also included some polyethylene to modify it's properties.