The baffle is simply glued to the interior of the left/right/bottom/top. PL Premium adhesive is stronger than the wood so it won't go anywhere. It also fills gaps so your cuts don't have to be perfect. But you don't want to slide a glued edge into position; it makes a mess.
I usually clamped parts till the glue dried. Sometimes I used a pneumatic 23-gauge pin nailer; the nails just hold the parts till the glue dries---they aren't structural.
My order of construction tended to avoid multiple glue joints in different planes, just to avoid sliding glued edges into place. And it kept me from touching sticky edges while manipulating the parts.
Basic construction steps:
- Cut all the parts. I used the OP's idea of making the port brace run all the way to the baffle for strength.
- Cut baffle hole. Drill bolt holes, install tee nuts for speaker and grille clamps
- Drill connector holes in back
- Black paint: bottom of port shelf, both sides of port brace, rear half of bottom. So when you look inside the port it's not bare wood. This is much easier to do before assembly.
Gluing sequence:
1. Braces to left and right. Port brace to bottom. The two top braces are aligned under the handle screws so longer ones go through into the brace. The flange screws aren't important so they just go into the top.
2. Baffle to left side, port brace to bottom
2. Port shelf to left side
3. Back to left side and port shelf
4. Right side to back, port shelf, and baffle
5. Bottom to left, right, baffle; port brace to port shelf
6. Top to left, right, back, baffle
As I mated the major parts, I glued brace ends to the other parts, e.g. the left brace got glued to the top and bottom. This stiffens the brace a bit more.
Now that the box is complete it's time to measure for the grill cloth frame; 1/16" of slack around all four edges allows room for the cloth.
Then I loaded the cab with the driver and a single connector (screwed a scrap block to seal the other one) to run a leak test. I ran 25Hz thru the cab and listened thru a plastic tube (like using a stethoscope). If there was any pulsing air on a seam it would immediately show up. Only one leak in one cab; mark it and seal it later.
Balance the cab front-to-back:
- Temporarily install the metal grill and grill cloth frame, then set the cab on a piece of pipe. Find the center of gravity. That's where the handle belongs. Mark its position for cutting.
Remove grille, driver, and connector
Seal any air leaks, cut handle hole
Bondo (fiberglass auto body putty) makes a good filler for any cracks, nicks, or holes in the cab surface.
Sand the cab with 60-grit on an orbital sander. I masked the area under the handle flange for a better seal. A quick coat of cheap satin black latex paint on all exterior surfaces including baffle.
First coat of Duratex using a 1/4" nap roller. I cut it in half; a short roller is easier to handle. No need for Duratex on the baffle; it'll be hidden by grill cloth. But it's now black.
Second coat of Duratex using a texture-roller.
The handle gets black caulking under its flange, then it's screwed in with drywall screws. Longer ones for the actual handle; shorter ones are fine for the flange.
Load the cabinet, install the metal grill, velcro for the cloth grill frame, rubber feet, connectors. Note: I spaced the feet so they fit nicely inside the top of a small milk crate. The Speakon NL4MPR round-flange connectors got large rubber washers for a tight seal.
Make music.
I think that's everything.
While waiting for glue and stuff to dry, I did other things: build the grill-cloth frame, solder wires and connectors to one Speakon jack. I also included jumper wires to reach the second Speakon but didn't strip them. This saved time later; just had to strip and solder to the other connector before loading the driver.
Oh, one important thing: Be sure you have the polarity correct. I used a battery to verify polarity on my other cabinets and matched it. No phase problems.
