AA&D's Drywall Repair Process
 

Here is a picture of the hole:

Step 1 - We will cut out a square area in the drywall just big enough so the edges are clean as above.

Step 2 - We will cut out two strips of plywood or OSB particle board (as shown to the right) that are about 4 inches longer than the hole. I would recommend plywood, but if you use the OSB particle board make sure it is at least 5/8" thick so screws can fasten securely. 

Step 3 - We then place the wood strips inside the hole and fasten with drywall screws as shown below.

Note: You will notice where one screw was taken out - this screw stripped the board and would not hold securely.  If this happens take the screw out so it doesn't work its way up through the surface later on. Plywood backing would have been a better material to use since it is more solid than the OSB board.

Step 4 - We will cut a patch piece of drywall about an eighth of an inch smaller in each dimension. We then fasten the patch piece securely as shown here.

Step 5 - We will use a 4 or 5 inch putty knife to place a very thin coat of joint compound (mud) extending several inches beyond the edges of the hole making sure not to put too much compound on.

Step 6 - After the mud is thoroughly dry, we will use a dry 10-inch knife to knock off any bumps or high spots.

Step 7 - We will use the 4-inch knife to apply another coat of mud that is about 1 or 2 inches beyond the first coat.  We then wet down the 10-inch knife and draw off most of the compound by applying steady pressure while moving the knife across the surface as shown to the left.

Step 8 - Next we scrape the surface down with the dry 10-inch knife as we did in step 6. 

Step 9 - We repeat Step 7 and place another coat that 1 or 2 inches beyond the last coat.  We use the wetted down 10-inch knife to draw down the surface. Y

Step 10  - Next again we scrape down the dry surface with the dry 10-inch knife. We level your surface free of bumps or ridges by using your knife to level things out.

Step 11 - We will place another coat of mud that overlaps the edge of the area as shown below.  We use the wetted down 10-inch knife to draw down the surface to make this a very thin coat - this will be your final coat except for touch up.

As you can see above, most of the compound is drawn off with the 10-inch knife.

Step 12 - We scrape down the surface again with the dry 10-inch knife and the dry 4-inch knife.  We find we can apply more pressure with the 4 inch knife gripped with 2 hands. We knock off any ridges or high spots. 

Step 13  - We take a trouble light or lamp and shine a low angle light on the surface of your drywall repair.  We apply small amounts of well thinned out mud with your 4 inch knife to fill in scratches, depressions, pinholes or other defects.  We immediately use the 4 inch knife to scrape off most of what was applied.

Step 14 - Lastly, we scrape down the surface again with either dry knife.  Then we sand very lightly with 220 grit or 400 grit paper.  If needed touch we up with small amounts of mud again. The entire area from this small hole ended up being 15 inches across, but the end result is a surface that shows no trace of damage.

Here's the patched area, primed and painted.  Even with the low angle light (see on right), there is no sign of the drywall repair to be found!