If you’ve ever seen a professional drywall builder, you’ve probably thought to yourself, “I can.” And probably on the first try – and the tape didn’t stick and the grout had lumps and the burrs would never go away – you thought, “I can’t do that.”
In fact, you probably can. Once you know what pitfalls to avoid and have a little practice, you should be able to finish a lot of drywall with just a little bit of sanding.
Grinding is the key. It’s labor-intensive, time-consuming, chaotic, and boring. The less you have to do, the better your technique will be.
Don’t think you’ll find shortcuts. Shortcuts are exactly what creates a bad drywall job. Prepare yourself for the meticulous process of following each step completely and thoroughly, and you will be rewarded with a wall practically indistinguishable from plaster of paris.
A graduation job consists of three phases (four cleanups). Ideally, you’ll complete one before moving on to the next. In reality, you might be at level 1 in one place and level 3 in another place. If you are confused, draw a note on the wall.
Stage 1, the primer:
1. Open the joint and mix with a dry blender or a clean, strong stick. You want the compound you apply to be as smooth as possible. Take a couple of cups on the knife and set it on the hawk (a flat metal or wooden plate with a handle in the bottom) or in the assembled pan. Make sure there are no lumps. You may want to add a few drops of water and mix thoroughly for a creamier consistency.
2. Use a 4 inch drywall knife to spread a thin layer of compound over the seam. (When the drywall is hung properly, most of the seams join two beveled edges, creating a slight indentation. Some butt joints are inevitable and harder to work with as you start with a flat surface and the first layer of the joint should be as wide as that Knife, with no gaps or voids, and between 1/16 and 1/8 of an inch thick.
Measure the paper drywall tape. You can cut it with a knife or scissors, but the standard method is to rip it against the knife edge. (Make sure the knife is clean, and use a hard, flat surface underneath it.) If it’s a long seam, you can do this in two or three parts, just slightly overlapping the tape where it is connects. Work a vertical joint from top to bottom; On a horizontal side, determine whether you are more comfortable starting at one end or in the middle and exercising in both directions.
Embed the tape into the joint by pressing it with the blade. Try to use long, even strokes. It’s about avoiding bubbles or wrinkles. It may take a few tough passes for the tape to be fully embedded. Push the compound out from under the edges of the tape and squeeze out any bubbles. Bubbles tend to move in front of the knife. If a bubble seems too big to just squeeze out, stop and hold the tape with the blade, lift it from the end back to the bubble, and then tie it back on.
Fold the tape along the groove at the inside corners, apply a thin layer of compound to each side of the corner, then tie the tape in on one side. On the outside corners, apply a metal corner bead that is nailed extensively on both sides to keep them flat and close to the surface. If the corner bead is not flat enough, problems will arise later. Use the 4-inch knife to apply grout to each side. Scrape off excess. (Don’t worry if the edge is a little rough. This is one place you always have to sand.)
3. Once the tape is embedded, scrape off the excess joint with the 4-inch knife so the joint is smooth and the tape is visible. This step is important – if you don’t remove the excess, you’ll need to sand it later.
4. Allow the embedded tape to dry thoroughly. It usually takes at least 12 hours. (It will take longer if the humidity is high.) Do not rush. Don’t touch it until it’s dry. If you were careful while scraping off the excess, there is no need to sand at this point. (If you need to sand some spots avoid sanding the tape – this will blur the surface and make masking more difficult.
Level 2, the block coat:
1. The goal of this mantle is to cover the tape or corner bead. On the corner bead, use a 6 inch drywall knife to apply a second, thin layer of the compound. Don’t apply too much. You’d just have to sand it down later. On the joints, use the 6 inch knife to fill in the bevel and just cover the tape. Hold the knife on the composite side at an angle of about 30 degrees to the surface. Use long, smooth strokes and try to make the composite surface as flat as possible – not concave or heaped up.
It is difficult for an amateur to machine both sides of an inside corner at the same time unless you have mastered the use of a corner knife. We prefer to end one side at a time. It takes longer in hours but can be shorter in terms of actual work.
Keep the grout smooth and free of lumps. After a while, you will be able to judge exactly how much connection to make and how to keep it evenly along the knife. Don’t try to scoop too much at once. less is better
2. Allow the connection to dry thoroughly – again it may take 12 hours or more.
3. After the joint is dry, check for any ribs or lumps. If available, sand them with special 100 grit drywall sandpaper. Use a light hand with the sander – do not sand directly through the ITC bond to the tape or metal. If there are craters (places where the knife has skipped and left a shallow indentation) or grooves, ignore them. The top coat should take care of such defects.
Stage 3, the top coat:
1. Load the grout onto a 12-inch drywall knife. The connection should cover the whole knife. Apply with the assembled side of the knife at an angle of about 30 degrees to the wall.
Work from the corners to the center of the wall. Every time you stop a blow and pick up the knife, the consistency of the connection means a line will be pulled out of it with the knife edge. You can grind burrs by picking up the knife. However, it is easier to do this if they are in the center of the wall rather than in the corners.
2. Feather the edges. To do this, press the blade of the knife against the wet edge of the joint. Hold the knife out at an angle so that you are only using about the last two inches of the blade and the outside point is about an inch above the edge of the joint. Gently move the blade over the joint. It’s a little hard to describe, but basically you will be beveling the edges of the wet joint. (If you just kept stroking the knife flat, you’d just keep spreading the mass, and eventually the knife edge would leave a burr in it. If you tried to smooth that burr you would get another one in the middle … and such continue.)
3. For the final pass on the damp compound, run the 12-inch knife straight along the joint in one long stroke. That should smooth everything and blend into the bevels.
4. Let the joint dry thoroughly and then finish sanding. If you’ve gotten really good, there shouldn’t be much to grind. Joint compound dust is one of the most insidious substances that humans know. it will go anywhere. Wear a dust mask and eye protection. Be careful with a fan in the room; The suction of the dusty air is fine, but you don’t want to just keep the particles moving. If you don’t want the dust to get into an adjacent room, seal that room with tape and plastic – don’t forget about the registers. If you have a duct system that circulates air, you may want to turn it off so it doesn’t let the dust circulate.
Some people smooth the dry coat with damp rags. It works well when there is a place that needs a lot of smoothing and it can create perfectly feathery edges. However, there are some problems. You need to be careful not to wipe off so much material that the tape gets wet. In this case, you will have to start over on that joint. In addition, the connection picks up any texture from the material. It’s difficult to keep the fabric flat enough to avoid patterns in the mix. (If the patterns aren’t too pronounced, you may be able to remove them with a very light sanding operation.) The other thing to avoid is getting the bare paper cover of the drywall wet, which will destroy it.
5. Clean up thoroughly. Dust the walls with a feather duster or dust mop, then sweep, vacuum and wet wipe. You may need to repeat this process a few times, but it’s worth it if you minimize the amount of dust that comes out. Before painting, wipe the walls one more time with a dry rag.
Created in black and white, it all sounds difficult and boring. It’s not that bad. As you continue, you develop a rhythm and can move around pretty quickly. Having the biggest, baddest boom box you can afford helps when blowing out your favorite music. Go ahead and sing along. We do it.
Next: When walls just need to be repaired.
Tips for drywall finishing
* Pay attention to the connection. Stir thoroughly and remove lumps before use. Don’t leave a crust of hardened compound on the sides of the bucket – keep scraping it out. If a crust forms on the surface, scoop it out and throw it away.
Do not put any hardened compound from the falcon or the composite pan back into the bucket. Throw it away.
Keep the lid open while you work to keep dust and debris out. When you’re done for the day, clean the bucket and seal it tightly.
* Keep the tools clean. Scrape them off after each pass over the joint.
When you are done with the day, scrape the tools thoroughly and let them dry. Sand down before use to remove residue.
Do not use the knives for any other purpose, e.g. For scraping paint or opening cans. If you get a cut or a bent edge, it will leave a mark on the joint.
Mr. Johnson is a construction manager for Neighborhood Housing Services in Baltimore. Ms. Menzie is the Home Editor of The Sun.