hey Guys,
I’m doing some very visible smoothwall drywall taping/mudding and can’t seem to get rid of the little marks from sanding. I am using the screen type sander with 220 “grit” the finest I could find and am still leaving little marks on the finish. I am on my 5th coat too! Any suggestions? How forgiving is the paint?
Thanks!
Replies
The paint is "pretty" forgiving. Especially if you use a good primer.
However, sand with the pole at an angle. When the screen or paper is running straight, it puts scratches in the finish.
Thanks!
I'm using a hand sander, any technique for that?
Try a rotary or criss-cross motion and use a light touch.
"Sand" it with a damp sponge, like a tile sponge. It will smooth the small ridges and fill in the scratches, and it will remove all the dust too.
I'm sorry, I thought you wanted it done the right way.
Stop using screens and go back to paper.
F
Try the black paper like the body shops use, silicon carbide I believe.
220 is a decent all around grit.
Do yourself a BIG favor, and try to learn how to skim out the imperfections with compound, rather than sanding them out.
Sanding sucks, and real pros don't.
I'd rather skim coat the whole job than touch the sandpaper once.
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
[email protected]
I'd love to skip sanding, but another problem I seem to run into with my mud coats is getting rid of the tiny "drag lines" (I'm assuming dried much chunks??) no matter how tight I keep my knife. I'm using the topping style compound. Any thoughts on that and how to get rid of them? I vaccumed the wall with a dust brush beforehand but can't seem to stop the 'grit'.
Thanks!
Apply thinner coats. Spread it around and then scrap/ trowel it off. Any "tails" left by your knife of trowel will have so little mass and structure, that a 12" knife will easily scrape it away once the wall or ceiling has dried.The tighter the angle you keep your knife, the more material will remain on the surface. Pay attention to cause and effect. The wall will tell you what you are doing wrong and right.How are you holding the knife and how big of a knife are you using on what coat? Are you sanding between coats? That's a big no-no. The most you should do is scrap the wall with the knife you are about to skim with. This not only cleans the walls and removes the high spots, it also sharpens the knife and gets rid of any burr it may have gotten. Be very careful though. After scraping a few walls, knives become quite sharp in the process and can be dangerous if not handled properly.Hope this helps,Frankie
I started with a 8", then 10", then 12", then 14" and now a 16". I know probably overkill, but what can I say I am a perfectionist! I have been sanding between coats and just using the ready-mix topping compound.
It's funny, the same hand movements seem to produce different results on different joints. On some sections, it's perfect, smooth, level and not a groove or streak in sight, while in other places I keep getting the groves and places where the thin layer pulls away and leaves a small void. Would thinning help? I was just following the directions that said use straight from the can.
I know I should have a pro doing this, but I'm the general and it's a small job so a pro taper wouldn't touch it, so I was hoping to hone my skills in the process.
Thanks!
Another thing nobody seems to have mentioned is do not overwork any one spot. If you go over the same area too many times it's starting to set up and not 'fluid' enough. Get it good and leave it. Lots of folks recommend a dash of dish soap mixed in, will try that myself next outing in to the mud world.Let's not confuse the issue with facts!
Should later coats always be thinned more than the 'ready-mix' bucket comes?
Thanks!
I have always found it needed thinning. I use a half-inch drill with a mud mixer, and for the finish coat I use topping compound, and thin to the consistency of mayonnaise.
What Franky said............and keep your tools and compuond bucket clean. You should have a pail of CLEAN water handy at all times, keep the sides of the pail wiped down and the lid clean and well seated to close.
Keep your tools clean to, stop what you are doing evry so often to clean your tools, and I use a hawk..........those little rectangulay thingys are for chickens, plus I'll never figure out how to load up a 16" straight trowel from one of those things.
If you are working from the same lump of compound for a while, it's gonna start drying out, if its getting small and hard to move it's done, either put it in the pail and remix with a dash of water or better yet toss it. Compound is cheap. If you leave the bucket open while taping it's gonna dry out.
For skimming, try thinning the compound with a LITTLE water.
Search the archives here for d mix and other taping vernacular.
Eric
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
[email protected]
Thanks got it!!
I think I just realized why everyone doesn't go for the ready mixed compound! Although, I've never seen topping in a mix form.
5 coats. If you want it that smooth and you put on that many coats you can probably just use your hand. Try it, you'll see dust come off.
Oh, I see, I've had it backward. I'm supposed to sand with my bare hand. I thought the technique was to spreading it on with my bare hands and then sand 90% of the stuff off.
What Ed Hilton said. Sponge is the last step in a clean smoothwall finish. Takes off any hard edges that would make a shadow. Blends in and fills imperfections.
Tom
I have done alot of finishing Im not a pro, and I have seen some pro jobs done (fast and out). I have learned less is better. build up in layers,smooth each layer. And I sand the third and final coat. With a sanding block. Very lightly. Also mud and move on to next area. Dont try and finish all in one coat.
To control scratch marks first condition the screen by rubbing a wood block over the surface with particular attention paid to the corners where the folds can cause a hard edge. Or change to fine sandpaper on with a foam backup.
Edited 4/19/2005 3:15 pm ET by Jeff2
When we have it pretty good we go ahead and prime it with "First Coat".
Then we use thinned mud and bare light bulbs and do touch ups.
The mud doesn't dry out near as fast. Another thing about this approach is the thicker fills will shrink back unpredictably even if you have them perfect when you touch them with the water based paint. Sealing the heaver fills off eliminates that headache.
After those are sanded or sponged we prime again with First Coat. It's more work but we get good results. Hope this helps. (also we have started adding the soap to the mud- as described on BT)
I'm no "real" taper by any means, but I've gotten good smoothwall results in very few coats (2 0r 3) with all forms of compound. The ready mixed stuff is fine, but don't use it as-is. When you open a box or tub, you'll find that the material has a cheesy,stiff texture which can almost be cut like cake. You need to stir this well. This step makes a huge difference - you'll know when it's mixed because you can feel it become soupy throughout.
Keeping your tools clean is next most important. Like someone said, keep a 5 gal. bucket on hand with a little water and a brush or sponge. I also keep a wet towel over my shoulder and constantly wipe my knives.
your goal should be to lay the mud on and smooth it in just two passes, hitting each spot and moving on. The mud starts to dry immediately, and that's how you get the mystery crumbs. Also, once the paper is wet for a couple of minutes, it gets mealy.
If you have to sand something, use a long flexible pole sander held at a very low angle to the surface, and sand in a light, orbital motion - keep your body loose.