Drywall mudding 101

[StaggeringGoat]

The drywall in my shop is only taped and has the first layer of mud, otherwise it's not finished. I'm trying to finish off just a small part of it smooth before I paint it. This is my first attempt at working with drywall and I don't like it.

I bought some "premixed" joint compound in a box, it seems too thick to me. It's extremely hard to spread out on the wall with my 12" knife over the joints. Can I/should I add a tad more water to the mix?

Secondly, what grit sandpaper should I be using to remove all this joint compound when it dries? I've been using 220 but I think that's a bit too fine?

 

[Rich H.]

I never met anyone who liked it

Add water and mix it until the consistancy is similar to cake frosting.

Most pros try to not sand it at all if they can help it.
If your skills are as amateur as mine, try 120.

Don't ever sand it just to remove little ridges from the knife edge, it just creates more problems....scrape them off with your knife instead. You'll most likely find you can get away with a whole lot less sanding, sometimes none at all.

There's a link to a good drywall forum on my build thread, very helpful as long as a guy can read past attitudes and so on.

Good luck

 

[Leadfoot3232]

I'm no pro but have had more experience mudding than I EVER wanted...I cover with about a 6" knife then come back and smooth with a 12"..When smoothing with the big knife,you want to put more pressure on the outside of the blade away from the joint and less on the joint..basically you want to leave more mud over the joint and feather the outside to flush..If you do this down both sides of your joint it will take a minimum, if any sanding..Use drywall screens for sanding, not sandpaper,paper clogs easily..I've done an entire room with one screen..I'm sure others with more experience than me will chime in..good luck, with practice it'll get to where it ***** alot less..LOL

and like Rich said,mix some water in,cake frosting would be a good consistency..I'll go a little thicker if I'm working a ceiling..I use one of the cast aluminum mixers from Lowes in my 1/2" drill and "whip" it til its completely smooth..

 

[nehog]

I bought some "premixed" joint compound in a box, it seems too thick to me. It's extremely hard to spread out on the wall with my 12" knife over the joints. Can I/should I add a tad more water to the mix?

Perhaps. But I'd do the first two passes with the thicker consistency and a smaller knife. Less shrinkage that way.

Secondly, what grit sandpaper should I be using to remove all this joint compound when it dries? I've been using 220 but I think that's a bit too fine?

Either use the mesh type made for this application (there is a special applicator for that paper that is open to allow the dust to drop through the back) or wet finish with a sponge. I do wet finish when I can, much less dust and mess.

 

[steven083008]

Wet finishing with a sponge is the way to go! It doesn't work for all situations, but if you have a relatively good finish, then using a sponge works awesome. If you're like me and some how manage to get little air bubble looking spots, a sponge can smooth those out as well.

In the future, I recommend you buy the powder mix, and mix it yourself. You can get exactly the consistency you want, a better finish, and you don't end up wasting nearly as much mud. I throw the leftover dry mix into a 5 gal. bucket and keep it around for the next job that comes up.

 

[JimVonBaden]

How porus of a sponge do you use?

I need to do a little mudding, and hate the dust of sanding, plus it is a garage, so it doesn't have to be perfect.

Jim

 

[cowboy73]

Definitely add some water to the mix and use the drywall sanding screens.

 

[steven083008]

Lowe's has a "wall paper sponge" that is very similar to what I used. I don't know how else to describe it. I've only used the one sponge so far, but I assume you don't want to go too porous.

 

[Stephenw]

I've done a little mudding and have gotten fairly good at it.

I use premixed mud in a plastic bucket and don't thin it at all. I like fiberglass mesh tape. I work in small amounts at a time and hold my mud on a hawk. I try to get it as smooth as possible so I don't need to sand. I knock the high spots down with a 12" drywall knife after the mud has hardened. If I need to sand, I use a wet sponge sanding block.

I scrape the excess mud off the hawk and tools directly into a trash can. I clean my tools in a 5 gallon bucket of water.

 

[Nighttrain]

Yes add water. The box mud even has it in the instructions to add up to so much. I used a little water bottle and as I remember it was about 3/4 full of water. Real good ideas above with the larger blades. When you mud the screw holes just dont mud each hole but start from top all the way to the bottom and spread a 4" wide patch of mud. then go to 6". The plan is not to do any sanding at all. I ended up mudding all the sheet rock on my walls to kinda float the whole piece. I only used about three of the screen papers to sand the entire garage. 12' walls by 120'. its hard work but you can do it. Pics in my build.

 

[W650Mike]

I’ll share some thoughts:

**** joints (end to end w/o taper) are the most difficult to float smooth since they are, by nature, raised due to the thickness of the tape; unlike the tapered edge joints.

Remember the tabs that you tore off the ends of the paired sheets? If you are careful, they will come off in one continuous strip. You can create a small depression at the **** joints by stapling that strip to the studs on either side of the **** joint stud – thereby effectively raising the sheet at the adjacent studs which in turn creates a depressed **** joint. A strip of roofing felt will also work.

As for mudding, add only as much water to your topping compound as minimally necessary to be able to spread it comfortably. Most DIYers are out of their league with a 12” knife. Switch to a 10” (Goldblatt with a very slight concave edge) for better control and less pressure/fatigue. Flex the knife as needed by applying pressure with your index finger (or thumb) to feather the outer edge. Try this w/o mud: hold the knife at about 25º to 30º to the wall and flex it. A good knife should flex with moderate finger force, but not be too flexible.

And finally, applying less mud and having to add another coat or touch-up a few areas is much easier than extensive sanding. Sanding is what maakes drywall taping ****.

Most tapers (that I know) are in the bar by 3pm so...

 

[ranger302]

I have a trick for you. Add some Dawn dish soap to the premixed stuff. This will help get rid of the "bubble" in the mud. It spreads alot better and will "feel" better.

hope this helps.

I worked 2 years out of HS hanging Dry Wall and mudded in more joints then I ever want to admit to.

 

[Tman]

Yup, dish detergent and a splash of water. Most folks mix too little, get a BIG drill and paddle and thouroughly mix it in a CLEAN 5 gal bucket. We buy by the box, pull out the bag, cut bottom of bag and squeeze mud into your bucket. Never let mud dry on the walls of the bucket and NEVER dip a dirty tool back in. This will keep dry "goobers" out of your mud. Tray or Hawk, use what you are comfortable with. The best mudder I ever watched worked in BLACK DRESS JEANS, fancy WESTERN SHIRTS and $500 boots, never got a drop of mud on him, old boy was a PRO

 

[gmein]

Yup, dish detergent and a splash of water. Most folks mix too little, get a BIG drill and paddle and thouroughly mix it in a CLEAN 5 gal bucket. We buy by the box, pull out the bag, cut bottom of bag and squeeze mud into your bucket. Never let mud dry on the walls of the bucket and NEVER dip a dirty tool back in. This will keep dry "goobers" out of your mud. Tray or Hawk, use what you are comfortable with. The best mudder I ever watched worked in BLACK DRESS JEANS, fancy WESTERN SHIRTS and $500 boots, never got a drop of mud on him, old boy was a PRO

Read this one again, been doing this all my life, rule number one. Cleanliness is everything. You will learn as you go, you are getting good tips here. But it is like playing an instrument, you will not become a virtuoso overnight, Hang in there! Practice makes perfect.

 

[Provincial]

I drywalled the entire inside of my 30x36 shop 12 feet high thirty years ago. Never again! I just finished a 2,000 sq. ft. "apartment" in my new shop building and hired out all the drywall work. It was the smartest move I have made. Unless you want to develop drywall finishing as a skill, use your time better on other projects.

Right now in Oregon building is so slow that you can get good work done for a very reasonable price. I got four quotes, and the highest was almost three times the lowest. The lowest had very good references, and did an excellent job. I think he underestimated the amount of work, but had the integrity to do it right anyway. This guy lives in Mt. Angel.

 

[internetdude]

I drywalled my 20x24 garage, even the ceiling. Mudding was not overly fun but I kinda actually like it. These videos were helpful!

and

I definitely recommend you watch both of them before starting any mudding project. If you do it right you (more thin coats) don't need to sand 'til the last coat, and you won't have too much to sand. I got my mud a bit too thick on the ceiling 'cause I rushed it and I was sanding over my head. That sucked. But I did better on the walls. My garage height is 13' so I was on two sets of scaffold to reach the ceiling...

 

[Frank The Plumber]

I hate it.

That said.

I use the bagged drywall compound. I use different dry time mixes for different coats. I'll use the fast bag mix for a base repair that will set hard in 30 minutes. yeah don't just mix a pail of that, I then go through the speeds working towards the slow dry at the end. I do about 3 or 4 applications, it depends how I feel it looks. If the last blend looks a bit hinky I may use a sponge to blend a thin coat into it to doll it up a bit. I usually only go 150 on sand cloth to finish. If you use a decent primer with a mid grade nap on a roller it will fill fine.

Still hate it.

But I hate the people who would enjoy it more than I hate the task.

I end up cleaning the G Damn house either way.

 

[bop_pa]

I've done plenty of drywall and taping but am still not a pro. It really is a skill. To watch the pros do it is amazing. That being said any novice can get great results with patients and lots of sanding. My best discovery was to rent a powered drywall sander I believe made by porter cable. It made sanding my baseMent a 3GS job instead of a week long job. It is worth the money to rent if you are a novice and will quickly knock down any high spots and ridges.

 

[Daedalus]

Awesome thread. Keep 'em coming guys. I got a kitchen that needs drywall before I can put the cabinets in!

 

[StaggeringGoat]

I'm sort of getting the hang of it. You guys are killing me with the no sanding....yeah right! Mine has to be extra smooth since I'm not texturing it...

 

[Jazz]

Not sure anyone mentioned it yet, but you should wipe down the joints to remove any dust after sanding or your next layer won't adhere well. Personally I've gotten to the point that I don't sand until the last step but will remove any high spots by running knife over them.

It's also important to note that ceilings can be difficult. That's why many houses have textured ceilings, to hide drywall issues.

 

[VairKing]

I am a pro. Been doing it for 10 years. Everything from huge shopping centers to small sheds. Most of the advice here is good.

2 basic types of mud. The first is what you have, premixed, redimix, vinyl, its called lots of things and comes in a bucket or box. This stuff shrinks as it dries, and is very easy to sand, so use it for taping and your final coat. Add a little water it does come too thick from the factory.

The second type is called fast set, 90, hot mud, etc, and it comes in the bag as a powder. You mix this with water and it cures similar to concrete. It gets rock hard when it dries and is hard to sand. It does not shrink at all, and if you have any voids to fill (cornerbead for example) and your first coat after taping should be with fastset, to avoid shrinkage and get a good base.

So tape with redimix, coat with a 10" knife with fastset, then coat a final time (you may need 2 final coats to make it perfect, don't sweat it) with redimix again.

The key is to only put on enough mud to just cover, an be careful not to leave hard edges. Being an ammerature you will have lots more sanding to do, but until you figure it out, that just how it is. Several careful light coats are going to be much easier to sand than one globbing coat.

 

[slghmmr88]

I have a trick for you. Add some Dawn dish soap to the premixed stuff. This will help get rid of the "bubble" in the mud. It spreads alot better and will "feel" better.

hope this helps.

I worked 2 years out of HS hanging Dry Wall and mudded in more joints then I ever want to admit to.

Yup, dish detergent and a splash of water. Most folks mix too little, get a BIG drill and paddle and thouroughly mix it in a CLEAN 5 gal bucket. We buy by the box, pull out the bag, cut bottom of bag and squeeze mud into your bucket. Never let mud dry on the walls of the bucket and NEVER dip a dirty tool back in. This will keep dry "goobers" out of your mud. Tray or Hawk, use what you are comfortable with. The best mudder I ever watched worked in BLACK DRESS JEANS, fancy WESTERN SHIRTS and $500 boots, never got a drop of mud on him, old boy was a PRO

How much dawn per box aprox. do you add. I've got two clients that like flat walls and those fricking bubbles are a pita. After long blocking (yeah they like em flat) the walls I usually have to come back and fill those holes after my first coat of tinted primer so I can see em. Dying to try this trick.