# Why are my patches humped?



## Driftweed (Nov 7, 2012)

So, I am convinced I am doing something wrong with 20 min mud. Been going patch crazy lately. 

I noticed when I do a patch w/paper and bucket mud its fine. But every time i use 20 min mudd its a visible hump.

Now i know you do 3 coats w/ 3 blades feathering each coat further out. But it just aint going right with the powder. 

I have tried mixing it ultra soupy, & applying it thin as hell. No luck. Seems that third coat is my undoing. 

Its not a huge hump, but the trained eye can see it. Any tips?


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## Burns-Built (May 8, 2009)

What kind of bag mud? Durabond will actually expand, I ran some tapers the other day with mesh and durabond then was talking to the drywaller and he told me about it. I got cocky and thought I'd try to get it in two coats and a skim, filled the taper and checked it with my knife perpendicular to the wall, just a hair under. Once it dried, a hair over...:wallbash: Not sure if easysand does the same thing or not.


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## Chad McDade (Oct 14, 2012)

I am pretty certain that all hot mud expands - but I don't think that the easy sand expands as much as the brown bag.


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## Metro M & L (Jun 3, 2009)

Check your sanding with a knife if youre worried about it. Id rather be high than low and have to paint another day. And that goes for patching drywall too.


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## Driftweed (Nov 7, 2012)

Yeah the second coat is 90% perfect. But theres always a pit or two to fill, so a third coat it gets. 

Customer (apartment complex) is just happy it doesnt look like a third grader did it.

Sheetrock 20 min mud.


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## MarkJames (Nov 25, 2012)

I don't do tons of patching, but my new habit is to check it with a little flashlight as I apply coats (like when doing a final sand). Sounds silly, but it helps to make sure I don't leave too much, even when the naked eye said it was tight. Easier than too much feathering and sanding.

(Edit: I mostly use "20" & "5"...and paper tape)


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## FRAME2FINISH (Aug 31, 2010)

Take a piece of rock turn it over , use a square cut a piece the size you need, then cut 2" perimeter around it gently snap the cut line leaving you with a thin piece of paper around the block you cut out!!

Throw in a wood blocker and mud it, once you got it down it goes quick!! Scrape the paper clean carefully


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## skillman (Sep 23, 2011)

FRAME2FINISH said:


> Take a piece of rock turn it over , use a square cut a piece the size you need, then cut 2" perimeter around it gently snap the cut line leaving you with a thin piece of paper around the block you cut out!! Throw in a wood blocker and mud it, once you got it down it goes quick!! Scrape the paper clean carefully


 Your sir just made a blow out patch . But I don't put blocks in wall . Just mud and go .


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## FRAME2FINISH (Aug 31, 2010)

If its small nether do I , but if it's bigger I will.

I like it because you don't have to tape 4 times, once your good you can cut up several fast and mud them even faster!

I use them when say a door knob breaks thru or someone deleted a box!


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## KennMacMoragh (Sep 16, 2008)

Hard to say because I don't know exactly how you're doing your patches. But I usually patch with mesh tape because it's thinner and transitions from the old to the new better than paper. One layer of hot mud, sand, then one layer of cold mud spread out about 12 inches to feather out the hump if there is one. Then sand, and sponge sand carefully where the new mud transitions to the old part of the wall so you don't see a line.


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## Big Shoe (Jun 16, 2008)

^^^^ what he said. 


Plus what I always say ..........Thin,thin,thin,thin.


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## SamM (Dec 13, 2009)

In my experience, the Sheetrock 90 always tends to expand a little. Dura bond expands like crazy though.


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## MTEC (Feb 24, 2014)

If you are using paper tape. Then here is ur problem you cant let the 20 m8n mud get too dry or it doesnt stick. Make it a touch wetter and what ever you don't use in 10 min is no longer sticky anough for the tape to stick.. dont forget it still needs time to dry if u do second coat right away itll pull the moisture from second coat then bubble.


Use durabond 90 sucks to sand. For first coat then any other mudd after


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## icerock drywall (Aug 16, 2012)

http://drywalltalk.com/showthread.php?t=4783


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## Jdub2083 (Dec 18, 2011)

I patch drywall daily with hot mud, 5 and 20. Its extremely easy to hump because it expands and starts setting in your pan. The mud starts to get a little hard and and you still try to roll with it and it humps because you can't pull it as tight. 

If needed I'll lightly sand the hump between coats. If its still there I just bust it out until its gone. It's gotta get painted anyway, who cares if its a 2x2 or a 4x4 area.

Mix a little at a time, it might help. And don't over agitate because that makes it set faster. 

Like others have said, try using mesh on patches instead of paper. Paper has a hard time bonding to hot mud sometimes and could be adding to the problem.


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## icerock drywall (Aug 16, 2012)

there is a way to make it flat...know one said it yet.


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## iDAHOchris (Feb 11, 2012)

if you arnt in too much of a hurry and can let things dry overnite try adding some AP to your hotmud mix. I will throw a couple scoops in a bucket while mixing or add a scoop to my pan while mixing. It will take just a lil longer to set but it will bond better and shrink back to a flatter patch. Or you can set your patch deeper than the wall its on and just fill.


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## icerock drywall (Aug 16, 2012)

iDAHOchris said:


> if you arnt in too much of a hurry and can let things dry overnite try adding some AP to your hotmud mix. I will throw a couple scoops in a bucket while mixing or add a scoop to my pan while mixing. It will take just a lil longer to set but it will bond better and shrink back to a flatter patch. Or you can set your patch deeper than the wall its on and just fill.


 you rock chris...:clap:


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## iDAHOchris (Feb 11, 2012)

Thanks Ice:thumbsup:. I have to admit I learned that from a fella that calls himself 2buck.


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## Driftweed (Nov 7, 2012)

Ok, shoulda gave better details on my methodology.

Doorknob holes i use the aluminum sticky patch. No issues there. Faster than your california patch.

My issues Arise on 2' *2' patches. I cut a square in the wall, insert 2 vert backerboards (1 leftside/1 rightside). Then I mount the patch. I'll mix a half pan of hot mudd with cold water. The first coat I call the "slop coat". I'll just slop it on the patch, put on my 2 vertical pieces of tape and drag my knife over them to set the tape. Then I will do the same for the top/bottom pieces of tape. After all tape is set, i cover it with the first coat and let sit overnight.

Day 2: sand, recoat/feather. Paying special attention to thickness so that all is as smooth as possible. This coat should make patch nearly invisible. Dry all day.

Coat 3: sand. Mix mudd runny as possible to fill pits left from sanding. Be careful to only fill pits.

Thats my process. And it works for the most part. Proof:



















Seems though if i mix mudds bad things happen. Like hot/bucket/hot


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## icerock drywall (Aug 16, 2012)

Driftweed said:


> Ok, shoulda gave better details on my methodology.
> 
> Doorknob holes i use the aluminum sticky patch. No issues there. Faster than your california patch.
> 
> ...


the size of the patch don't change the time it takes to fix it ...and like chris said the drywall needs to be deeper to make it flat....there are ways to do that. and my small patch work takes 20min to fix 3 coats from the time the drill is in my hand and the washing is done.:clap:I know everyone thinks there way is faster:laughing:


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## endo_alley (Apr 9, 2013)

On larger square patches I almost always use a feather edge plastering rod. After the patch is taped, especially if it is paper tape; I fill the inside of the patch with mud and pull a plastering rod over it to screed it dead flat. Then I run twelve inches around the outside of the patch and feather the outside edge. Sometimes this takes a second coat with a plastering rod in a perpendicular direction. After that dries I do I tight skim to smooth it out. If the patch is large enough to span wall studs or ceiling joists, I shim the entire exposed framing with one layer of drywall shims. I break the shims six inches from the perimeter of the patch. In this way I am creating a slightly recessed joint to finish. It doesn't matter to me if it is hot mud or drying mud. The mud doesn't expand. It only shrinks a little. If your finish is crowned, it is most likely because the compound was not applied perfectly flat in the first place.


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## Driftweed (Nov 7, 2012)

so your saying use 1/2" drywall to patch 5/8" ? did i read right?


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## icerock drywall (Aug 16, 2012)

Driftweed said:


> so your saying use 1/2" drywall to patch 5/8" ? did i read right?


no that's nuts I make buttborad strips for repair that needs to be flat


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## Driftweed (Nov 7, 2012)

ok thought i mis read that.


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## icerock drywall (Aug 16, 2012)

Driftweed said:


> ok thought i mis read that.


if you cut the drywall out to the stud...you will have a hump ....but if you put osb and shim it the drywall will suck in like a seam and the patch is flat...sometimes just osb work fine


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## Jdub2083 (Dec 18, 2011)

Driftweed said:


> Ok, shoulda gave better details on my methodology.
> 
> Doorknob holes i use the aluminum sticky patch. No issues there. Faster than your california patch.
> 
> ...


Another tip that helps that I forgot to mention earlier is after you hole is squared off and cut out, take your utility knife on an angle around all the edges. Do the same thing with your patch piece. It makes the patch a little more forgiving with humps at the seams by creating a v.


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