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For my first-ever drywall taping attempt, I (predictably) messed up. Taped the walls (three coats), then added primer (two coats) and semi-gloss Behr paint (two coats). Reinstalled my lighting and decided everything looks terrible.

I've been told I should either sand the paint/drywall down or put more mud over the whole thing. I don't know what I'm doing, but I do want this to look good. Are there good techniques/approaches to get me out of my mess?

More pictures here

wall light

  • Also, there's very little sanding involved with taping. The way laypeople talk about it you'd think you're expected to sculpt like Michaelangelo, but that's not how it happens. The only sanding should be a super light pass at the end to knock off miniscule knife lines and other tiny imperfections. You don't shape the wall by sanding. It's all about thin, careful application with the knife. Being an amateur I sometimes take 4-5 steps to tape walls, but my sanding takes mere minutes and a very light touch. – isherwood Feb 19 at 19:51
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    Also also, walk the room with a strong light source. Hold it near the wall and look. You'll see imperfections stand out like the Andes. I never paint until I've done that at least twice (the second time after repairs). – isherwood Feb 19 at 19:56
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The whole wall doesn't need a skim coat. That patch just needs touch-up spackle, sanded correctly.

The picture does a good job highlighting what you failed to do: bevel any divots or ridges with a sanding sponge during the final sanding. This is not something you can do easily with a pole sander; it'd be easier with just the paper in your hand if you've no sanding sponge. Use a swirling motion to reduce any deviation to a nominal profile. Fudge it.

It doesn't have to be flat, it just has to not have any ridges that will catch light and show the imperfection. Keep this in mind when sanding the extra coat you're going to put on, to fill these giant voids, that are next to the ridges that are covered in paint and are at this point basically unsandable.

Mudding an optically flat wall is beyond most people's abilities (if not, the general realm of possibility). The closet you're going to get (or ever really need to) is 'looks' flat: nominal.

If you can feel a 'catch' with your fingers, you're not done sanding yet.

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Ugh. The paint is just going to make what should be pretty easy rather more difficult.

Even your drywall pros sand stuff - they just waste far less time than amateurs trying to get the mud perfect (and messing it up more) - get it on, get it dry, sand, next coat. Drywall mud is made to be easily sanded. Paint, not so much.

Don't even think about painting it (next time) until the surface is about perfect.

Start sanding. The only way out of this mess is to get through it, which will be something of a chore with all that paint on there. Always use a block of some sort when sanding drywall - you want to knock off the high points and leave the low ones alone (then fill the low ones left with mud, dry, repeat....)

..and (perhaps now more obvious to you) don't work in the dark - bring in bright, harsh portable lighting and get it on the walls as unflatteringly as possible so you can see what you are doing. This is what I use cheesy halogen worklights for...

  • I agree with sanding down because layers on layers of different materials are a good recipe for it to start peeling off, I use 300 & 500w halogen lights at an angle and this shows every defect, most try to put on two much and this appears part of your problem, sand it down without tearing the paper and you may only need a skim coat of topping mud, use a wide knife. If using a pole or hand sanding pad 3 strokes or more to sand means you are being sloppy or putting on two much in my opinion. – Ed Beal Jan 10 at 18:42
  • I disagree. Sanding latext paint is a bugger. Strategic skimming is the obvious and easy solution, from my perspective. – isherwood Feb 19 at 19:52
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You need to get a wire brush and scratch the hell out of your wall in the bad area and a little outside of it.

Add mud to flatten area. Let it dry. Scrape any high areas (with mud knife). Add a big layer of mud for a second coat. Scrape then thoroughly sand.

You are going to have to prime and paint the area. If you just slightly prime the already painted wall but use a thicker coating for the new wall you can do this where it is basically unnoticeable. This is a total of a couple hours over 3 days. I would try to remove as many things from room or tarp since to sand right you will make a mess.

(I am guessing from your pic - and it isn't very good - that you are not using enough mud and not sanding enough. If done right you only sand on your last coat - a lot. )

  • Also, be sure to use a topping compound instead of the normal mud when you do the final coat. Topping compound is typically creamier / smoother, and sands easier. Which makes for less work when you're finishing the final coat. – cathode Apr 16 '15 at 3:11
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Do not sand or scuff up anything.

Apply a coat of primer over the whole thing and allow to completely dry.

Use setting type 90, light weight joint compound, in small batches, to smooth out the imperfections. (It comes in a bag.)

Do not sand between coats - if you do, use a well wrung sponge, to remove excess dust, before applying another coat of mud.

Use the edge of a knife/trowel, to knock down any ridges/clumps, prior to additional coats of mud.

When you are satisfied, that you have a reasonably uniform surface, begin blending in the edges, with 120 grit drywall sandpaper. You can use 100 grit on thicker sections or ridges, but try to stick with the 120 as much as possible, following up with 120, if you use 100 on any spots. (Attach the sandpaper to a proper sanding pad/block - the bigger, the better.

Take your time, and start with the small spots first, gradually moving towards the bigger sections, as you build confidence, in your work.

When in doubt about drying times, there is nothing wrong with overnight - you'd be amazed what a fresh outlook in the morning, can add to the experience.

The wider the area, that you cover with mud, and subsequently blend into the surface below it - the flatter, the finished surface will appear, when painted.

If you have a portable shop light, or an old table lamp - put it opposite of you, close to the wall, while sanding, using the shadows, to even out the surface. (Turn off the decorative lamp, in the pictures too.)

  • I agree, by why the setting compound? Any vinyl-modified premix should do just fine, no? It's certainly easier to work with. – isherwood Feb 19 at 19:53
  • @isherwood - A.) It will get done faster. B.) Setting type won't give him the option to mess with it for an hour, and so.. it will get done faster. C.) A+B= it will also look better. Rookies are as much or more impatient than us, but for different reasons, yet they expect the same results. I always have a bag of 90 available - it lasts forever-ish, and as primarily a finisher, I don't have to worry about running out of working time, if I want to make a full pan's worth. He only has to mix a little at a time... so the sooner he can get at the next batch, the more meaningful each coat will be. – tahwos Feb 21 at 1:11
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Make it easy on yourself if you can.

  1. Sand as much of the paints gloss off as you can.
  2. With a 10" or larger mud knife or trowel add more mud in a thicker layer. If there are ridges that is ok.
  3. Go back and add a thin layer of mud that you have slightly thinned with water or later/acrylic paint. Just a couple of spoon full of either.
  4. As you trowel it on the thinner mud will deal the low places.
  5. Wipe your tool dampen it's edge and work from bottom to top or vice versa. Make sure the trowel is almost flat on the wall. Wipe off excess from your trowel. If large clumps start to adhere to the tool... Dampen the tool again. You can do it I did. It was my 1st time also.

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