HOW TO 2ND COAT DRYWALL BUTT JOINTS
If you want to learn how to 1st coat butt joints go here How to 1st coat butt joints
(What's A Butt Joint??)
Butt Joints happen any place two ends butt up against each other. Unlike the tapered edges on the top and bottom of sheetrock, butt joints are just flat (There is no cavity to fill with mud). If you were to take a wide knife, and place it on a butt joint, you will see that not only is it flat but many times you will be able to rock the knife because it is a little humped already. What you are trying to do is build up the mud on each side of the tape to make the joint as flat as possible. You don't want to make a bigger hump. See what I mean??
The picture below shows what we are trying to do here. 1st coat (Yellow) we will use a 10 inch knife. Build up each side of the joint. The 2nd coat (Blue) we will use a 12 inch knife, coat the middle of joint.
Step 1: Sand
Using a sanding pole and some 80 to 120 grit sand paper lightly go through your project and sand any edges and lap marks. You shouldn't have to sand too much here. All you want to do is knock off any edges from the 1st coat so there won't be any problems with the 2nd coat.
I like the new round sander made by (Full Circle International)
Not only does it remove more material faster, It really makes your joints flat.
A regular square sander might make a butt joint smooth but it will leave it humped.
A medium sanding sponge works great for your angles, corners and detail work.
Step 2: Mix Mud
Mix up your mud. To learn all about mud and how to mix go here All about Joint Compound
Thin your mud down with a little water. Mud straight out of the bucket is too thick for anything. Any pro will tell you that you must thin it down. You want it smooth and spreadable like pudding. Once you have some good mud mixed up and ready to go, get a little bit into your drywall pan. For the 2nd coat you will need a 12 inch knife. Always keep your pointer finger in the center of the knife, this will give you more control. Always try to keep the finger side of the knife as dry and clean as possible. Most knives have a logo or something on the handle on one side. I always make the logo side my finger side. Decide what side you want your finger side to be and stick to it. If you're flipping the knife all the time it will get all wet, dirty and sloppy and gross. You want your pointer finger to stay dry.
Step 3: Spread mud on center of butt joint
Using a drywall pan full of mud and your 12 inch knife, spread a nice even bed of mud down the center of your butt joint. Start at the ceiling and come down until you meet the recessed joint. If you're doing a lower butt, start an inch off of the floor and come up until you meet the recessed joint.
Just apply nice even pressure on the center of the knife (Notice finger location).
Step 4: Feather in outside edge (Right Side)
By moving your finger a little right of center, you will gain more control on the right side of the knife. Slowly pull down the butt, the right corner of the knife is tight against the wall. The left corner of the knife is slightly lifted away from the wall. Practice this a few times. What you want is to leave a nice little ripple line inside the joint a few inches.
Step 5: Feather in outside edge (Left Side)
By moving your finger a little left of center, you will gain more control on the left side of the knife. Slowly pull down the butt, the left corner of the knife is tight against the wall. The right corner of the knife is slightly lifted away from the wall. Practice this a few times. What you want is to leave a nice little ripple line inside the joint a few inches.
Step 6: Pull your knife down the middle
Make sure to have your finger in the middle, Bring the knife down nice and easy. Don't push to hard or you will wipe all the mud off. Just nice even pressure. Your butt is now 2nd coated and should look like the picture below (on the right).
Good Job!!
You just 2nd coated a butt joint. Let it dry overnight before you sand
How about a free video ??
You can also find some good drywall tips in the "ASK THE PRO" section
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