# Is this not the easiest way for a perfect drywall skim coat?



## ront02769 (Nov 28, 2008)

Sounds pretty simple in theory....but I don't think that it will replace the guys around here who spend years perfecting their craft. Ron


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## mako1 (Jan 7, 2014)

You're going to have a hell of a tuff time skim coating with 5 or 20 minute hot mud.With you're idea and a 1/4" trowel you're also putting way more mud on the wall than needed.


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## joecaption (Nov 30, 2011)

Ever tried to sand hot mud?


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## Sir MixAlot (Apr 4, 2008)

Or you could skim coat the walls using a 1" nap and paint roller to roll on thinned out joint compound and then smooth out with a wide drywall knife. :yes:


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## gunner666 (Jul 16, 2014)

I've heard of rolling-on thinned out joint compound, seems like it will just come out all textured though, and the smoothing out you mentioned with a mud knife after is where I think many people will create waves that can be seen especially with glossy pain and when light hits it. 

True, sanding hot mud is not easy at all. If just sponging hot mud when it's almost set isn't possible, maybe this should only be done with regular drywall compound, not the easy-sand light weight though because it's just less strong and more prone to cracking from house settling or bathroom moisture, doors shutting etc, but the stronger green lid USG is easy enough to sand/sponge. 


I didn't mean 1/4" thickness, I meant 1/8th max at a time because it might shrink if too much is applied. If the wall's really bad, it might need two phases. If you can't find a trowel that's notched only 1/8th, then a 1/4 would work if angled correctly i.e 1/4" angled 45 degrees would make 1/8th grooves. 

The idea is similar to a scratch and brown coat of exterior plaster. They trowel the mud on then put the key grooves in it, let it dry and put another coat on top.


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## gunner666 (Jul 16, 2014)

another way would be use a curved trowel, one used for leaving a slight hump over joint paper. Make vertical lines with the curved trowel, the humps will be a bit under 1/8" thick and taper off a the sides. Let dry. Use the fattest part of the hump as a screed guide for the next coat. using a straight (not curved) trowel. IOW, if you have a 4 foot plaster darby, you can make your first vertical application as much as almost 4' apart, but if you have a 14" straight trowel, you'll need to make the first curved vertical lines about 1' apart.


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## ToolSeeker (Sep 19, 2012)

Why are you trying to make it harder than it is. In the first post hot mud is hard to work with especially in a large area, it's hard to sand and doesn't paint well. Your second idea will leave you with a wavy surface that will take a ton of sanding.

Sir Mix has about the easiest way. remember it's a SKIM so you take almost all of it back off. Since it is thinned compound you can take it back off with a rubber squeegee from Sher. Wills. called a magic trowel. This leaves a fairly smooth surface that can be easily sanded.


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## bjbatlanta (Jul 16, 2008)

Agree with Sir Mix. Simplest way to do it....


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## gunner666 (Jul 16, 2014)

I don't care how many years in someone has or anything, I think it's humanly impossible to freehand a perfect skim coat that won't show under certain lighting and gloss paint, especially a ceiling.

It's been said that overlapping strokes with the notched trowel will cause oozing out the sides and ruining the grooves on the sides of the trowel, however, you can leave a couple inches space between the strokes in the first phase and fill them in with the second coat. 
You can tilt the notched trowel as much as you want to make it thin/ thick as you want. 

Only thing is someone said the second coat might soak into the first notched coat (because it's porous and might suck in the moisture) causing it to possibly deform, but maybe that depends on the materials, and maybe even if it does shrink it, you can do a third skilless application of spreading mud straight across giving steady pressure using the existing ridges as the screed guide. Or maybe you can spray/roll something on the notched coat so it makes a barrier to block the first one from soaking the second's moisture but still allowing the mud to stick to said coating. 



Do whatever you want, just thought I'd share the idea hope someone can use it.


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## bjbatlanta (Jul 16, 2008)

I don't think anyone is "attacking" your concept. Just trying to keep it simple. The whole point of "glaze coating" a surface is to make the face paper on the drywall the same consistency as the finished joints. The paper is rougher and more porous. All that is needed for a level 5 finish is to roll a coat of mud on, wipe it down, lightly sand the whole area and you're done. Seems a whole lot simpler than your process. And you don't need 1/8", 1/4" buildup of mud to achieve what is needed. And as you stated above, if you skim your setting compound with ready mix, it WILL shrink and another coat will be necessary. Roll and wipe down will save a whole lot of time, energy, material (aka money), and achieve the same thing. But do what you think will work best in your particular case...


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## gunner666 (Jul 16, 2014)

I was just saying like if the wall's old and has many bumps and divots or if it's wallpapered and you want to skim coat over the wallpaper and paint over it instead of ripping off the wallpaper.

I might actually tests this on a scrap piece of drywall using hot mud and then sponging (hot mud=hard to sand but if sponging is good enough, then it is) and with regular green lid USG mud and seeing if it actually shrinks or not, paint it gloss and look at it at an angle in the light. I have no plans to skim coat but just thought I'd share the idea.


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## bjbatlanta (Jul 16, 2008)

Well rough walls are another story. I thought you were talking about new work. I'd still just apply with a 10" knife, probably first coat with setting compound. Skim with ready mix. First coat one direction, second coat opposite way. Probably some minor touchup before sanding because ready mix over setting compound often leaves more "craters". Again, your system should work. Just seems like more work, but i do this for a living. Give it a try and let us know how it worked out.....


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## chrisn (Dec 23, 2007)

bjbatlanta said:


> Well rough walls are another story. I thought you were talking about new work. I'd still just apply with a 10" knife, probably first coat with setting compound. Skim with ready mix. First coat one direction, second coat opposite way. Probably some minor touchup before sanding because ready mix over setting compound often leaves more "craters". Again, your system should work. Just seems like more work, but i do this for a living. Give it a try and let us know how it worked out.....


exactly:thumbsup:


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## ToolSeeker (Sep 19, 2012)

A LOT more work and a lot more sanding.


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## bjbatlanta (Jul 16, 2008)

Amen, but give it a shot!


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## gunner666 (Jul 16, 2014)

if you freehand it, go with a rounded trowel aka pool trowel and it will leave less lines, tip I picked up from giordano plastering on youtube. 

He's got good videos but you'll catch him doing counterproductive work sometimes like a plaster lath ceiling was half falling down so he tore it out and stood there lookin up picking out all the lath keys and priming it and then mixing plaster and troweling it on when all he had to do was screw a couple $9 drywall boards up after the demo and give it an imperfect skim coat to match the rest and it won't crack or bubble again like plaster even if they wanted to match the original.


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## jeffnc (Apr 1, 2011)

gunner666 said:


> Take a square notched grout trowel.


Grout trowels are not notched, ever.



gunner666 said:


> Mix up hot mud aka setting type mud aka the powder you mix water with instead of the premixed


Setting compound is not AKA powder mix. Drying compound comes premixed or as a powder. It's only setting compound if it says setting compound on it.



gunner666 said:


> Next, coat the whole wall with the notched trowel trying to keep the same angle of the trowel i.e the blade of the trowel is always as close to 45 degrees to the wall.


It will be almost impossible to maintain the correct angle across the entire project.



gunner666 said:


> Another idea is find something that's hard plastic or metal like 1/4" wide strips that are only 1/8" thick and 8 feet long to go from ceiling to floor. Use a fast-setting but weak adhesive and fix the strips to the wall vertically every few feet. Then just screed the mud on using a 4 foot darby or something using the strips as a guide like how you screed sand for a paver patio base using 1" pvc. When it dries, pull the strips off the wall (might have to dig out a small section of dried mud from around the strips to get behind it to pull off). Then fill in the spaces the strips were using the first coat of dried mud as a guide.


Sorry, but this is a just plain bad idea. That's WAY too thick for a skim coat, and even if it weren't, it almost guarantees a wavy job. The standard way for doing this is far more accurate and appropriate. I'm not sure what problem it is you ran into with glossier paints (obviously one of the reasons you'd want to skim coat in the first place), but you're better off solving that problem.


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## jeffnc (Apr 1, 2011)

gunner666 said:


> True, sanding hot mud is not easy at all. If just sponging hot mud when it's almost set isn't possible, maybe this should only be done with regular drywall compound, not the easy-sand light weight though because it's just less strong and more prone to cracking from house settling or bathroom moisture, doors shutting etc, but the stronger green lid USG is easy enough to sand/sponge.


I think you have a misunderstanding of what a skim coat is exactly. You're putting it on the entire wall, but the vast majority of it is scraped off. You're not going to get cracking, because the voids you're filling are practically invisible and represent about 2% of the wall space. It's almost all removed.


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## jeffnc (Apr 1, 2011)

gunner666 said:


> another way would be use a curved trowel, one used for leaving a slight hump over joint paper. Make vertical lines with the curved trowel, the humps will be a bit under 1/8" thick and taper off a the sides. Let dry. Use the fattest part of the hump as a screed guide for the next coat.


WAY too much compound going on the wall. Not what a skim coat is.


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## jeffnc (Apr 1, 2011)

gunner666 said:


> I don't care how many years in someone has or anything, I think it's humanly impossible to freehand a perfect skim coat that won't show under certain lighting and gloss paint, especially a ceiling.


You're right that you can't "freehand" it, but your technique is the freehanding one, not ours. The standard technique basically takes the compound off at the wall surface. i.e. using the wall surface to press your tool against, you're not freehanding anything. It's only with your technique that you're trying to freehand ridges that you will screed against. Sorry, that's lunacy :jester:


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## chrisn (Dec 23, 2007)

jeffnc said:


> You're right that you can't "freehand" it, but your technique is the freehanding one, not ours. The standard technique basically takes the compound off at the wall surface. i.e. using the wall surface to press your tool against, you're not freehanding anything. It's only with your technique that you're trying to freehand ridges that you will screed against. Sorry, that's lunacy :jester:


I really think it best to tell him how you REALLY feel about his method, not just beat around the bush.:laughing:


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## jeffnc (Apr 1, 2011)

gunner666 said:


> I was just saying like if the wall's old and has many bumps and divots or if it's wallpapered and you want to skim coat over the wallpaper and paint over it instead of ripping off the wallpaper.


I've skimmed over wallpaper (specifically, wallpaper that had the outer vinyl layer pulled off, leaving the rough paper subsurface layer.) After a coat of Gardz and quick sand, the amount of compound used in a skim coat is miniscule. It merely fills in the nearly microscopic nooks and crannies. Nowhere NEAR 1/4" or 1/8" of compound being put on.

Also, the point of skim coating is really to fix the texture of the wall, not the porosity. If your primer is good, and presumably you'll be priming your walls before putting on glossy paint anyway, then that is what will fix the porosity problem.


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## jeffnc (Apr 1, 2011)

chrisn said:


> I really think it best to tell him how you REALLY feel about his method, not just beat around the bush.:laughing:


I know, that was rude, but he is just resisting too much


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## 123pugsy (Oct 6, 2012)

jeffnc said:


> I know, that was rude, but he is just resisting too much


Thanks Jeff.

It's fine if he's resisting and he wants to try it, but a lot of people read these threads and someone may actually try it and destroy their wall.


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## chrisn (Dec 23, 2007)

123pugsy said:


> Thanks Jeff.
> 
> It's fine if he's resisting and he wants to try it, but a lot of people read these threads and someone may actually try it and destroy their wall.


Which ,according to all the pros here, would be foolish, it seems.


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## gunner666 (Jul 16, 2014)

_Setting compound is not AKA powder mix. Drying compound comes premixed or as a powder. It's only setting compound if it says setting compound on it._

ok good to know, makes sense to sell non- setting type without water weight also. 



_It will be almost impossible to maintain the correct angle across the entire project._

It's the same thing as skim coating a whole freehand though, either way you have to maintain an angle. I'm not talking about putting mud on and scraping it all off for a level 5 finish or something, I'm talking plastering over textured wallpaper or scratched walls etc.




_Sorry, but this is a just plain bad idea. That's WAY too thick for a skim coat, and even if it weren't, it almost guarantees a wavy job. The standard way for doing this is far more accurate and appropriate. I'm not sure what problem it is you ran into with glossier paints (obviously one of the reasons you'd want to skim coat in the first place), but you're better off solving that problem._

I don't have the exact source but a very credible one said to get 1/8" mud on the walls.


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## jeffnc (Apr 1, 2011)

gunner666 said:


> _It will be almost impossible to maintain the correct angle across the entire project._
> 
> It's the same thing as skim coating a whole freehand though, either way you have to maintain an angle. I'm not talking about putting mud on and scraping it all off for a level 5 finish or something, I'm talking plastering over textured wallpaper or scratched walls etc.


No, it's not the same, precisely because this is almost exactly the same as a level 5 finish. You don't scrape it all off (obviously, or else there would no point), but almost all. I think the problem is you have a misconception about how much you're supposed to put on.

The reason it's not the same is because with a notched trowel, the precise angle you hold the trowel at dictates the depth of material you put on. For example, if you're using a 1/4" trowel, you basically never get 1/4" of material on there. It's a different amount depending on whether you hold the trowel at 45 degrees or 50 degrees. But with a flat trowel, or knife, or squeegee, which you should be using, the angle makes little difference. You're basically holding it right up against the wall and there are no notches. You're primarily filling in the low spots, not trying to build up material.



gunner666 said:


> I don't have the exact source but a very credible one said to get 1/8" mud on the walls.


I'm sure we'd all be curious to read the source, because if it tells you to put 1/8" of mud on the walls for a standard skim coat, then it's just not a credible source.


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