I was going to start a new thread but the more I think about it, I don't think Brad documented this part of his build in any detail (maybe he did, I don't remember) but if he did it would look like this so what better place for it? Hopefully Brad won't mind.
Step 1: Cut a bunch of 1/2" plywood into 1.5" strips on a table saw.
Step 2: Use a mitre saw to cut the strips to the lengths needed. My frames are 23.5" tall and various widths wide. Since we know the strips are 1.5" wide and we're using lap joints, then we subtract 1.5 from whatever length it is we need and cut two strips at that length. Once assembled, they'll be the length we want. In this case, I need both sides of my two 23.5" tall frames that I'm doing tonight, so I cut eight strips at 22".
Step 3: Cut the top and bottoms of the frames using the same method as step 2.
Step 4. Take the strips to our jig for assembly. The top left corner is four pieces of stacked plywood forming a perfect right angle (use a carpenters square). Off to the right, I have marked lines off at the various widths I will be using PLUS my 23.5" mark.
Step 5: Get out the glue and nailer. This particular Paslode shoots 18 gauge brad nails. I'm using Titebond on Big's recommendations.
Step 6: Put a scrap piece of our 1.5" wide plywood into the corner of the jig. Now take one of our sides and place it into the corner as well, flush with the top. Slather it up with glue.
Step 7: Add same sized top piece to the mix. The scrap piece of 1.5" ply in the corner gives us the perfect offset. Double check this by looking to the right of the jig and verifying that we're at the right line on our length.
Step 8: Shoot about 10-20 nails into the boards depending on length. Glue might seep out... no biggie.
ALSO: I should also mention that these are the nails I use.
Step 9: Repeat for the other three sides and you'll eventually have a stack of lumber that looks like this...
Step 10: Now we head back to the jig to assemble our sides. Place them into the jig like before and have at it.
FREE TIP: When nailing the corners, don't put a nail in the middle. That's where our speaker ball will end up /and we'll need to drill out for it. Nails are not good for that.
Step 11: Stand back and admire your perfectly square frames.
Step 12: We're doing a 3/8" roundover so we're going to need a router. This is a Bosch Colt and I love it. I also have ZERO routing experience and its small size makes it much less intimidating than a full size router, IMO.
Step 13: Route the edges... nice and slow. Watch your fingers.
Step 14: Admire your nice rounded edges for a bit and then take them to your theater.
Step 15: So this frame is going to go on the middle row which means we want to add just a bit of a gap between it and the other frames because I'm guessing two layers of the fabric is going to be about a 1/16 to 1/8" so we need some breathing room. I'm too lazy to actually measure it so I use a knife blade. Looks good to me.
Step 16: Put a drywall screw into the frame to hold it in place.
Step 17: Drill a pilot hold through the frame and into the furring strip behind it at each location that you want a speaker grille ball and guide. We'll be doing one on each corner.
Step 18: Now remove the drywall screw and frame and drill out for the grille guide. I'm using the Parts Express heavy duty ones and that means a 9/16" spade bit into the furring strip.
Now we have four of those in the wall.
Step 19: Head over to your frame and drill out for the balls. These require a 7/16" bit for this part.
Once this is done, you've got a frame with a bunch of balls in the corners (I gotta quit saying balls).
Step 20: Put it on the wall. Here's the end product of about an hour of work tonight (taking these pics slowed me down a lot and reminded me why I don't actually have/want a build thread). As you can see, I have two frames in the middle row as of tonight.
That's it. Rinse and repeat, ad nauseum and with any luck we'll get a theater as nice as Brad's.