Testing durablity of my paint job and some Qs.

I brought a sample of the old paint(I chipped it off from the wall) to lowes and the guy "guessed" it was Semi-Glass and he recommended me to primer it first. So I spent $20 on a gallon of primer and another $25 on a gallon of paint(light green color).

When I got home I did a little bit of research on if I needed to put primer on the wall first before I should paint it. I got mixed answers. Some said that I needed to while others said that it is not needed.

My understanding is the main job for the primer is to make a hard to paint surface paintable. Semi-Gloss is somewhere in between I guess.

Well I painted a partion of the room WITHOUT primer, I painted directly over the old paint(white). I put ONE coat of the paint only. I waited about an hour for the paint to dry. The paint felt dry to the touch. If I stand 2 feet away, I can not see any flaw or running on the paint. But if I stand up real close, about 6 inch, I can see really small white spots on the "bumps" of the paint, kinda looks like the paint is not thick enough(The old paint small bumps on the surface, not like the ceiling popcorn type but it is not flat). I think those white spots where because I used cheap paint, Valspar from Lowes. If I just put on a 2nd coat, it looks like it would be ok.

Now my question is, from what I just did, is that a valid way to test to see if the paint will stay on in the future?

 

Priming is generally a good idea, if you are going to change the color significantly (in which case you have the primer tinted to a touch darker that the finish color) or if you have a lot of repairs to do and want to prime to lock in the repairs. I would not suggest high or semi gloss on walls, flat or satin has a more expensive look and creates an air of spaciousness. So in your particular case, I'd say the green isn't covering the white in one coat, partially due to the translucency of the paint, so you can simply add another coat and take the primer back, or have the primer tinted close to the green, and prime first then finish. The cost difference and durability either way seems negligible. Personnaly I would prime and then apply a coat of flat on the walls and satin on the woodwork if it were my house.

Bill

 

I am done painting the room without primer. When I was testing the paint on the wall, I was using a paint brush. When I did the actual paint, I used the roller and it didn't leave any spots and the paint seems to be thicker. I did one coat of paint and so far it looks good. I still have a little bit of the paint left. Would you recommended I buy another gallon to put a 2nd? Would adding a 2nd coat of paint make the paint last longer?

 

Did you sand the semi-gloss before painting? I don't always prime latex semi-gloss when recoating with flat - mostly depends on the colors.

Primer wouldn't help much at this point. I suspect the reason your paint didn't cover is two fold - not a high grade of paint and painting over enamel usually causes the paint to be applied a little thinner [because it won't suck in] Another coat of paint should fix the coverage issues and yes, 2 coats almost always wear better than one.

 

No I did not sand anything.

When I bought the paint I only bought one gallon. If I go back to buy another gallon, should they be able to mix me another one to be the exact color? They have the color code and everything. I know the machine will do the work, but I don't know how accurate it is. What are the chance or ratio that the machine will give me a color with a slightly different shade?

 

It's always a good idea to sand glossy surfaces - promotes good adhesion.

At a regular paint store the odds of getting an exact match are good but it may be iffy at a big box paint dept. If you cut and roll another coat, it shouldn't matter if it's off slightly. Even an exact match might appear slightly different with/after better coverage.

 

Do a cross cut tape test (you will need to spackle and touch up the spots after testing)

Use a razor knife and cut a "tick tack toe" cross hatch - about 2" square. Then rub some masking tape (not easy release type) down over the cross cut and pull off. The paint should not come off with the tape.

Be sure the latex paint is cured before testing as uncured latex will not pass a tape test in this situation. Wait a month before testing to be sure the paint is cured (maybe even a bit longer).

If the paint passes, spackle over the cross cut and touch up the spot ( it is best to do the test in an inconspicuous area).

If the paint fails ........ well you may have a problem on your hands in the future.

 

Thanks I will do that. So it takes a month for the paint to cure? Does that mean I shouldn't stay in that room until the paint is cure? Right now when I touch the paint, it is dry. Is it ok for me to move the stuff in the room now?

 

Drying and curing are different. Latex paints dry quickly - in a few hours, but cure rather slowly. A month is a good "rule of thumb". Deep tones may take longer because of the added glycol that comes automatically with universal tints. (Incidentally the reason there are really no totally environmentally "green" paints - is because you will be adding universal colorants which contain solvent - glycol. Unless of course, you stick with the pure white base color only)