# Homeowner in need of pro advice



## painting_n00b (Apr 20, 2021)

Hey all...
I just finished skim coating over an inconsistent texture on the walls with three coats. So far so good. After sanding there were a few spots that I knew I would need to touch up after priming. However after I sprayed primer on the walls and took a closer look while drying I notice these small dimples or what seem to be popped air bubbles everywhere on the wall. I know that I had left a couple spots with pin holes on the drywall from the mud but these are different. I attached some pictures as well as the primer that was used. Any help would be appreciated. Thanks!


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## Shelwyn (Apr 10, 2015)

If they bother you a lot, do a very light skim coat of drywall mud over them, push the drywall mud in the holes then wipe it all off. Let it dry and do it again if the wall is still porous. Then take a fine sanding sponge and sand it smooth, and get rid of any edges and primer over it or paint it if you already painted. Just a tip if you leave a thick coat of mud and paint over it, you'll see bulges. Also, make sure the drywall mud dries, or it might look warped if it's wet, then you paint over it if the coat you leave is thick. Make sure it's very light to fill in the porous holes.


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## grubburg (Jun 17, 2021)

did you mix the drywall first with a drill and egg beater?


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## Plaster123 (Jul 10, 2021)

How long did you wait to prime and paint?


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## restored (11 mo ago)

painting_n00b said:


> Hey all...
> I just finished skim coating over an inconsistent texture on the walls with three coats. So far so good. After sanding there were a few spots that I knew I would need to touch up after priming. However after I sprayed primer on the walls and took a closer look while drying I notice these small dimples or what seem to be popped air bubbles everywhere on the wall. I know that I had left a couple spots with pin holes on the drywall from the mud but these are different. I attached some pictures as well as the primer that was used. Any help would be appreciated. Thanks!


The pin holes are pockets of air. Mostly likely you applied the new compound over a painted surface that has already been sealed. The product your using , compound isn't penetrating through the sealed surfaces like it does on drywall or onto compound, unsealed. When ever I patch holes in drywall or plaster with a drywall patch, wall of ceiling, the mud will bond, but you will have pimples due to the air in the water, and the sealed surface behind it. In most case the bond with be sufficient. You will need to skim these areas a couple times. knock off any high spot expands with your 6 " knife. Skim again. If your doing a entire wall that has been sealed with a oil paint, I mix Elmer's white glue with warm water and paint on. Add a little warm water to your compound, mix, and skim. THe glue & water acts like a bonding agent. You may still have air bubble voids on the first coat, but piece of mind that mud will bond to wall. Always happens patching spots and mudding over the painted areas to blend in. The drying process is quicker with each coat as the water with the chemical reaction of the compound is being absorbed and bonding to the new compound. Personally I don't like using durabond for the first coat, because it sets quick and I have always questioned is there enough time for the water in the mixture work it's way through the painted surface to create a reliable bond.I actually double coat when I'm using compound. First coat use tape at all seams. Make sure the crease in the tape points out, toward you. make sure any voids in the seam is full of mud, and plenty of mud behind the tape before you squeeze out. I second coat then, using a 10 or 12" curved drywall trowel. Plaster trowels are flat, drywall trowels have a small concave outward curve in the middle of the trowel. Apply second coat, it may look like a circle, depending on the hole your patching. The tape may appear to bubble right under the joint. If you have filled the void and then evened off like you would taping drywall it will contract when it dries. If the tapes bubbles under under where the surface is solid you most likely don't have enough mud under the tape. More often this won't show until it begins to dry. if noticeable right off, pull the tape away and add mud, repeat your smoothing out action again with a little less pressure. Redo the second coat on that area. If you have a bubble under tape after drying cut the bubble out, it will have the paper come with it and hit with mud like you would a screw hole. IF it's right at the seam and you see a void, lack of compound fill and use another small piece of tape and repeat the taping process. If the patch is a hole from say a door knob hole and the patch is a 6" square. The third coat of mud use a 14 or 16" trowel . You may to add compound to the middle using a 6" knife. there will be ridges you can scape down after drying. This size hole, my patch ends up being about 3 ft. round, feathering out . Touching up and adding compound with your 6" taping knife for me is always needed. A forth coat is more common than not. with the 6" knife. fill low spots, should be small, feather the outside edges more pressure being used on the outside perimeter of the patch. This procedure may happen with all 3-4 coats. The drywall knives used for me are important. Not a fan of a flat wide knife, unless I'm skimming large areas, after these patches areas are complete and it's the flat wall appearance we all strive is your goal.


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