# drywall joints not flat



## mickey69125 (Dec 8, 2007)

Hi, been a member here for quite a while but haven't posted a lot. I always say you can learn more from listening than talking, so that's what I've been doing, listening to all the excellent ideas here. So here is my problem. When I mud drywall joints I sometimes get a concave joint, (center of joint is lower than edges). I use a 6" knife for the first coat, a 9" knife for the second and a 12" knife for the third. All of them are flex knives, I'm wondering if I should use a non flex knife for the first coat. I know that some of you are going to say "hire a pro" but in my rural area and the size of jobs that I usually do (one or two rooms) that is not an option. Just looking for some advice as to what I need to do differently.


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## naptown CR (Feb 20, 2009)

mickey69125 said:


> So here is my problem. When I mud drywall joints I sometimes get a concave joint, .


 
The opposite is usually true The joint is actually LOWER in the center than at the edges on a taper joint? Try applying less pressure on the joint or a lower angle to the board sounds like shrinkage is happening. Does the tape ever show through?


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## master of none (Apr 27, 2009)

try running down each side of the joint with most of the presser on the edges.


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## JonM (Nov 1, 2007)

Try using a curved trowel...:thumbsup:


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## mickey69125 (Dec 8, 2007)

Naptown, no I never have a problem with the tape showing through. 
JonM, I've tried using a curved trowel and can't seem to get the hang of it, do much better with a knife.
Master, I will definitely try that.
Thanks all.


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## JonM (Nov 1, 2007)

mickey69125 said:


> Naptown, no I never have a problem with the tape showing through.
> JonM, I've tried using a curved trowel and can't seem to get the hang of it, do much better with a knife.
> Master, I will definitely try that.
> Thanks all.



Sell Knock-down....:clap:


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## naptown CR (Feb 20, 2009)

So you are a broad knife guy instead of a trowl. Try putting a slight bow in the 12" trowl about 1/4 inch or so and hold the knife at a very shallow angle. ( handle close to wall) One other thing are you watering your mud? this can cause excessive shrinkage too.


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## mickey69125 (Dec 8, 2007)

naptown CR said:


> So you are a broad knife guy instead of a trowl. Try putting a slight bow in the 12" trowl about 1/4 inch or so and hold the knife at a very shallow angle. ( handle close to wall) One other thing are you watering your mud? this can cause excessive shrinkage too.


Hadn't thought of putting a bow in the trowel, sounds like it might work, and no, I never water my mud.


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## JonM (Nov 1, 2007)

mickey69125 said:


> Hadn't thought of putting a bow in the trowel, sounds like it might work, and no, I never water my mud.



That is what I meant by use a curved trowel...they sell them already curved in a bunch of sizes


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## naptown CR (Feb 20, 2009)

JonM said:


> That is what I meant by use a curved trowel...they sell them already curved in a bunch of sizes


 but these are shaped like a concrete trowl and are used with a hawk. Not many guys use that method anymore. Before it starts... except those that do.


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## Tim0282 (Dec 11, 2007)

If your mud is too stiff, you will tend to push too hard and pull the mud out of the center and make it shallow. There is a front and back to knives. Look down the knife and you will see a very slight bow in the knife already. Sounds more like the mud is to stiff, though. And be careful to not sand too much in the center and take off what you put on.


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## Tim0282 (Dec 11, 2007)

Have you considered a couple boxes, a handle and a pump? Best money you've probably spent. Sure helps make the joints flat with the least amount of mud. So less sanding.


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## naptown CR (Feb 20, 2009)

tim0282 said:


> have you considered a couple boxes, a handle and a pump? Best money you've probably spent. Sure helps make the joints flat with the least amount of mud. So less sanding.


 huh?


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## Tim0282 (Dec 11, 2007)

Finishing flat boxes. Tape Tech, Columbia, North Star, there are several brand names. Just about every drywall finisher that does drywall full time uses them. Speed, quality precision tools.


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## Tim0282 (Dec 11, 2007)

http://www.all-wall.com/acatalog/Flat_Box.php
Here are just a few that are sold.


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## A+ Texture (Sep 23, 2008)

If your jobs are realatively small try using self stick mesh tape and hot mud. There will be less shrinkage and you can usually get away with 2 coats instead of three. Otherwise a curved trowel may be in order for boxed mud.


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## naptown CR (Feb 20, 2009)

Tim0282 said:


> Finishing flat boxes. Tape Tech, Columbia, North Star, there are several brand names. Just about every drywall finisher that does drywall full time uses them. Speed, quality precision tools.


 I'm old school dude


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## [email protected] (Dec 18, 2008)

Tim is right about your mud being too thick. Add 1/2 pint or so and mix thoroughly. And also about there being a bow in your knife already. Mark the top side and always use it the same way. And once you've done a joint you think is right, check it with the knife at a right angle to the wall, if you see daylight, you've pulled it too tight and need to reapply. Maybe the one biggest secret to finishing by hand is knowing when to quit f***in with it and leave it a little high and having a little bit to sand.


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## Muddauber (Nov 2, 2007)

naptown CR said:


> I'm old school dude



Old school?

I broke in the trade 36 years ago on these tools!


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## AARC Drywall (May 11, 2008)

OLD SCHOOL...get with the times.


lol


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## Double-A (Jul 3, 2006)

I'm so old that back in the day mud was really mud, literally. Drywall was something you got if you put the mud in the holes properly. 

If not, it was a wet wall.:w00t:


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## Glasshousebltr (Feb 9, 2004)

Muddauber said:


> I broke in the trade 36 years ago on these tools!


Are you kidding me? ......I would have never guessed the mud box has been around that long .....seems like yesterday some one handed me my first Banjo .....but then they freaked out and accused my kin folk of shooting at em while in canoes .......:blink:


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