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Finishing Drywall Joints!
Before starting the drywall taping process, make sure corner bead is installed on all outside corners. Also make sure that all the fastener heads are sunk below the surface paper. You can check them by running a taping knife over the board. If you hear a "click" you've got a nail or screw that needs to be sunk deeper. Just give the nails an extra tap, or give the screws a twist with a Phillips head screwdriver. Professional tapers sometimes notch out the butt joints so they have more space for the first pass of joint compound. This helps eliminate the "hump" that you might get when taping these joints. The entire finishing process is about a 4-step process. The first step is called the "tape coat." This is when you apply joint compound to the seams and embed paper joint tape in it. First Pass of Tape Coat: When working with pre-mixed compound, most professional installers will add a small cup of water to the compound to help thin it out so it will spread easier on the drywall and leave a thinner coat. The thinner the coat the less sanding you have to do. This also will break up any lumps in the compound from the factory. Mixing is done with a commercial grade paint mixing tool attached to a 1/2” electric drill. Start by shoving the paddle down to the bottom of the bucket to make a hole to the bottom and then pour the water into the hole. Then slowly begin too mix the mud with the drill. The consistency of the mud should be like a semi wet oat meal look. Mix about 3 to 5 minutes. Starting with the drywall ceiling spread a layer of "mud", as the professionals call it, over the joints. For this first coat use a 5" or 6" taping knife. Be generous with the mud at this point. Spread out more than you need to fill the seam. The trick to spreading out mud is to hold the knife almost vertical to the drywall when it's full of mud, and press it flatter as you move along the joint. This spreads the mud evenly over the whole stroke of the knife. The joint must be completely coated with the mud to avoid dry spots when the tape is applied. The tape must be completely imbedded in the drywall mud. Embedding drywall Joint Tape: For the second pass, lay a piece of joint tape over the center of the joint. Press it lightly with your hand--just to make it stick for now. Then go back and flatten the tape into the mud, working from the center of the joint out to the sides. You can use pretty firm pressure with this stroke. You'll end up scraping off some of the excess mud just leave some mud under the tape. As you tape, keep your knife clean. Constantly scrape it off the side of the pan. Mud that stays on your knife will dry out faster. Pull your fresh mud from one side of the pan and return the used mud to the opposite side as you scrape your knife between passes. This used mud is discarded before you re-load you pan with fresh mud! If you re-use it you will have a much greater chance of getting “rocks” and debris in your coatings. Smoother coats equals less drywall finish sanding!!! The next step for the tape coat is to spread a very thin layer of mud out on top of the tape. This requires a soft touch. The layer should be thin enough that the tape is still visible through the mud. The biggest trick to getting a smooth finish with a minimal amount of sanding is to get this and every coat as smooth as you can on each step removing all the excess drywall mud that you can. One method is to now use a wider blade knife ( 6”) to remove grooves and streaks on the surface of the tape joint while the mud is still wet. There'll be more coats to smooth it out later. Another trick is to stop and wash off your pan and knife blades to remove the dried “rocks” and mud about every third or fourth re-load of mud into the pan. Take your time with these steps and you will be a lot happier with the small amount of sanding needed at the end of your drywall project!!! Inside Corners: Inside corners also get treated with joint tape. There may or may not be tapered edges here, but it doesn't really matter too much. Slightly uneven walls won't be as visible in the corners as on a flat wall. Make sure the board is securely nailed as it will cause cracking later if the drywall is loose. First apply a thin layer of joint compound inside the seam and on both sides of the corner. Measure and cut off the length of joint tape you need. Then fold the tape in half and press it into the corner. Most brands of tape come with a crease in the middle to make this easier. Press the tape into corner. Then run a knife down each side to set it into the mud and to work out any excess mud. Lightly coat both sides with joint compound again. Outside Corners: The outside corner bead will have a little valley between the metal ridge on the corner and the surface of the drywall. Now you want to fill this with mud. With mud on your knife, run it down each side of the corner bead. Hold the knife at about a 45 degree angle; it should be touching the wall and the ridge at the corner. Scrape off anything that rises above that level. Clean off any bits of mud left on the ridge. You should end up with about a 4" wide band of mud on either side of the corner on the first coating. The next coating will be with a 8 to 10“blade and the final with a 12” blade. Mudding Fastener Heads: The last thing you have to do for the tape coat is to cover all of the screw and nail heads. It just takes a small amount of mud to cover these, but start by putting on more than you need and stroke it back and forth in different directions to work it into the dimple and cover an entire row of screws with one stroke. Gently scrape off the excess mud with the taping knife almost perpendicular to the surface. This will leave a very thin layer of mud all the way up and down the wall. The mud over the screw and nail heads will shrink a little, so you'll have to repeat this step with each of the next two coats. Again try to get as much excess removed as you can in these steps! Wrapping up for the day: When you finish the tape coat, you need to let it all dry at least overnight. There are quick set compounds now available which can speed up this process but always make sure the mud is dry between coats. If not it the mud will tear and smear. Clean all your tools real thoroughly. If you have any dried mud left on your knives it'll cause little gouges when you do your next coat. A light coating of WD 40 on the knife blades will prevent them from rusting over night as well as your pan metal. Throw out any mud left in your pans. Scrape down the sides of the mud bucket to remove any dried mud, and pour a little water on top of it to keep it from drying out. Pour this water off before using the mud the next time. Always keep the lid on the mud bucket as you are working.
Go to drywall sanding!
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