Helping a buddy out and his drywall sanding/patching skills are just terrible. His walls are primed as well.
What is the best way on sanding down a primered wall. I want to tackle the joint compound that is underneath the primer……and not go crazy on having clogged sandpaper.
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Replies
HA haha ahha oh man that is very hard if it already has primer on it, you may be able to sand some but be ready for loading up the screen/sandpaper. You may end up skimming over the bad spots to feather things out. You are a friend indeed.
Jeff
What he said
Good luck
Forrest
I hear ya ;-)Came ready to paint and I was like WTF is this.....
Pet peeve but it's just me that would rather get it right by cutting down than *patching* up, but due to time and ease, I think I may just skim on top to get things looking good.
I think skimming over is the only option. Sanding primer (or paint) is just about impossible. Once you break through the primer, the compound underneath that spot will get removed much faster than the surrounding primer creating a crater.
Of course, fixing it now will be harder than doing it right the first time. Why is it your responsibility to fix it if you were only asked to paint?
The next time I have to skim coat a wall, I'm going to give this tool a try: http://www.texmaster.com/magictrowel.html
-Don
If yu gotta do it, yu gotta do it. Been there.
What has worked for me was a coarse sanding disk (60 or 80 grit) mounted on a drill, not random orbit, just a drill. use the edge as gently as possible. Leaves lots of swirl marks, makes lots of dust, but cuts thru the paint and doesn't clog too bad with coarse discs.
Hope this helps. rich.
Often times I'll use the good ol' 2" carbide scraper and take down the high points agressively. It requires another coat of mud, but it can be faster than simply sanding and it sounds like you'll be adding more mud anyway.
:-)
So, what did you decide to do? And how did it go?
-Don
Guys who wanted the most perfectly smooth wall would primer it and then mud over the flaws, lightly sand and then primer it again.
Two secrets to getting a fast and easy skim coat, the right trowel and no sanding, just light sanding at the end. The trowel need the right curve or bow in it to eliminate lines, there is also a pool plaster's trowel, its center is higher than it round outer edges. Do not sand between coats, just scrape off lumps and bumps when dry with a straight edge.
If you mud over primer, do you need a bonding agent or a special mud or anything?
Bryan,No bonding agent needed. The beauty of primer is that stuff sticks well to it, by design.
Skim it, feather it in, and call it good. You'll open a huge can of worms if you try to fix it right.
Last week, I had a similar problem in an old garage. The rock had been hung sometime in the '50's and had been badly taped. The HO wanted it painted white and wasn't interested in ripping it down and rerocking. I spent two days fixing bad taping and fixing 50+ years worth of holes, etc. When I put on the first coat of primer, all the places I had missed suddenly glowed like Xmas lights. To add to the fun, some of the old tape released and bubbled on me - lol.
Another few hours of skimming and light sanding took care of most of the problems and the HO said he could live with the rest. It took three primer coats, but it painted out pretty well. Thank the gods for T&M work - lol.
You hit on the technique our painter used on our level 5 ceiling and smooth walls. He primers the whole thing first, then does all the touch-up. I think that he just spot-primered the patches before the finish coats. You're right - sure makes it easy to see all the problems!
I guess that even a blind hog finds an acorn once in a while. My "technique" certainly wasn't planned - lol.
That old drywall was the color of mahogany and I had taken down most of the light fixtures so the light wasn't very good. After the first round of patching the bad spots, the walls and ceiling were covered with white polka dots. I thought I had it nailed, but as I rolled on the primer, the places I had missed just lit up.
I usually try to avoid painting but if I ever have to do that again, I'll make it part of the process - it definitely worked - lol.