# Is it ok to patch hole in drywall using only hot mud?



## Marky82 (Dec 17, 2015)

I ran new electrical wires in my upstairs bathroom so it's now on its own circuit. I have two holes in the drywall I had to cut to run the wires into the electrical box. I attempted to patch one of them using 90 minute easy sand setting compound mud instead of cutting a drywall patch. I first screwed in 1/4" plywood to the back, then applied self-adhesive mesh tape to the plywood so there were no gaps. Next I mixed up some hot mud that had a thicker consistency and filled the hole. My next step is to lightly sand, cover with FibaFuse tape using the premixed joint compound.

I know I took the easy way out with this. I usually cut a piece of drywall instead of filling the hole with mud but when I was in my attic I saw what looks like holes that used newspaper as a backing. I would have never known there was a hole if I hadn't seen it from the other side.

Is what I did an acceptable way of repairing medium holes in drywall? I know the hot mud is stronger than the premixed stuff. If this method of patching isn't a good idea I won't do it again. I'll be remodeling the bathroom in the next year or two so I'm not too concerned about this particular patch but I wouldn't want to use the method on other areas of my house if it's going to crack.

*Here are some pics:*



















Thanks,
Mark


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## stick\shift (Mar 23, 2015)

You can do it this way. I would not but it's acceptable.


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## Marky82 (Dec 17, 2015)

stick\shift said:


> You can do it this way. I would not but it's acceptable.


Out of curiosity (I'm a drywall noobie) - why not? Is it more prone to cracking?


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## Gymschu (Dec 12, 2010)

I do it on occasion. One reason to avoid it is that hot mud is so much harder to sand than premixed. Nowadays the hot mud formulas are getting so that you can sand them ALMOST as easily as premixed. Also, hot mud is a little bit tougher to feather out around a patch, at least in my experience. I would use some tape around the perimeter of that patch for your follow up coats just to make it a stronger patch.


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## stick\shift (Mar 23, 2015)

As Gymschu explained, you're not proposing the easiest way to fix this.


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## Marky82 (Dec 17, 2015)

Gymschu said:


> I do it on occasion. One reason to avoid it is that hot mud is so much harder to sand than premixed. Nowadays the hot mud formulas are getting so that you can sand them ALMOST as easily as premixed. Also, hot mud is a little bit tougher to feather out around a patch, at least in my experience. I would use some tape around the perimeter of that patch for your follow up coats just to make it a stronger patch.


That's exactly my plan. I have FibaFuse tape which is supposed to be thinner and stronger than paper and better for butt joints (it's a newer project... had to special order from home depot). I'm going to use the premixed joint compound for bedding the tape/additional coats.

The reason I tried filling with hot mud instead of a drywall patch is it saved time, and was less messy, then cutting a patch and enlarging the hole in the wall to fit the patch.


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## Gymschu (Dec 12, 2010)

Marky82 said:


> That's exactly my plan. I have FibaFuse tape which is supposed to be thinner and stronger than paper and better for butt joints (it's a newer project... had to special order from home depot). I'm going to use the premixed joint compound for bedding the tape/additional coats.
> 
> The reason I tried filling with hot mud instead of a drywall patch is it saved time, and was less messy, then cutting a patch and enlarging the hole in the wall to fit the patch.


As a painter, I often use 5 minute, then 2 rounds of 20 minute if it's something that needs done quickly. If there's no hurry, I do the final coat in topping compound for easier sand ability. Absolutely nothing wrong with using hot mud for the final coat. Fibafuse is awesome.


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## firehawkmph (Dec 12, 2009)

For small holes like cutouts the size of a single or double electrical box, I will cut the hole with a keyhole saw but instead of holding the blade 90 degrees to the wall, I'll make it about 45 degrees. This leaves a bevel all the way around. Once I'm done running wires or whatever, I'll mix up some hot mud, butter the bevels, put the same piece back in, which because of the saw kerf will be a hair smaller than the opening. So it sits about 1/16" below the surface. I run fiber tape around all four sides and coat over the whole thing with the hot mud for the first and second coat. Final coat I use USG Dust Control premix. 
Mike Hawkins


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## Workaholic (Apr 1, 2007)

Marky82 said:


> That's exactly my plan. I have FibaFuse tape which is supposed to be thinner and stronger than paper and better for butt joints (it's a newer project... had to special order from home depot). I'm going to use the premixed joint compound for bedding the tape/additional coats.
> 
> The reason I tried filling with hot mud instead of a drywall patch is it saved time, and was less messy, then cutting a patch and enlarging the hole in the wall to fit the patch.


Following up the repair with FF and premix jc will ensure that your repair is not going to crack out

Personally I would of simply patched it with drywall and the FF from the beginning.


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## Gary in WA (Mar 11, 2009)

Marky,* no* air-drying all purpose compound with the Fiba FG mesh tape; https://www.usg.com/content/dam/USG...roper-joint-tape-white-paper-en-usa-J2140.pdf

Wear some gloves with the FibaFuse- if glue gets wet- could ingest directly through your skin, good way to see if allergic or not, though it's only 30% by weight- follow manufacturers recommendations; http://www.gtpro.com.au/technical/51-fibafuse-msds/file.html

Gary


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## Marky82 (Dec 17, 2015)

Gary in WA said:


> Marky,* no* air-drying all purpose compound with the Fiba FG mesh tape; https://www.usg.com/content/dam/USG...roper-joint-tape-white-paper-en-usa-J2140.pdf
> 
> Wear some gloves with the FibaFuse- if glue gets wet- could ingest directly through your skin, good way to see if allergic or not, though it's only 30% by weight- follow manufacturers recommendations; http://www.gtpro.com.au/technical/51-fibafuse-msds/file.html
> 
> Gary


I did use the setting compound to embed the tape. I mistyped in my other post. First I used setting compound to embed the tape then all purpose and I'm going to finish up blending the edges with dust control. 

Drywall is certainly an art! No matter how much I read, there's no replacement for experience. I'm getting better but I'll still have sanding to do. Kudos to the pros that can do it quickly and with minimal sanding. They don't get enough credit!


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## RickMacKay (Mar 23, 2016)

I've probably patched over 10,000 holes. This is not rocket science. The hot mud works for prefill on a hole that size. Just cover it with tape after it sets and wipe over it with a larger trowel and some pre-mixed all purpose mud. Paper tape will be fine, one tip is to soak it in water first and then apply it, it will stick better. One thin coat to embed the tape, then a second or third coat (if needed) to make the tape vanish. Scrape off any ridges with your taping knife, maybe light sanding.


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## gunner66 (Jan 3, 2017)

you're not really supposed to put spackle directly to wood. you patched the holes with plywood. I dunno about hot mud but I know with premixed mud it is said to not adhere to wood well. 
you might be able to use a bonding agent on the wood though. I mean, old lathe and plaster is plaster-to-wood but I see guys use a bonding agent also on the wood when doing a patch, and maybe their first coat (what they used back in lathe and plaster days) was hot mud and stuck better than premixed , but not to mention lathe is spaced to allow a mushroom key affect and hold the plaster in place.


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