Originally Posted by bimmaguy
Good luck with your build, OJ!
Still making progress when I get some time. I got to work on the baffles this weekend, and feel pretty good about the outcome. Maybe not 100% good... but at least 90%.
The first thing I did was clamp the 2 baffles together, use scrap MDF to make sure they were centered and wouldn't leave me with overhang, and then mark the centre on the smaller inner baffle. Then I drilled out a pinhole to use as a pivot for my router jig.
My jig is just a simple piece of smoked 1/4" plexiglass that I used way back on my original Tempest build, and have somehow managed not to lose, despite moving since then. We drilled and countersunk for the 3 mounting points on the router, and cut a hole in the middle. Then I just measure and drill the pivot holes as needed. In this case I think I went with 8 3/8" for the inner baffle, and 9 1/4" for the outer baffle. I set up a piece of 1/2" foam board to test with, since I haven't done this in about a decade.
I did notice some wobble, since the foam can't really hold the pin nail perfectly still, but I figured this was as much a conceptual effort as it was practical, and I just tried not to wiggle it too much. The inner baffle test piece seemed to go well.
The wobbles are evident, but the process went fairly smoothly, so I used that hole to continue on to the plywood inner baffle. That cut well, and was a pretty good fit. I probably could have gone about 1/64" smaller, but I'd say that's about as good as I can ask for without CNC help.
I cut out both baffles, and somehow had some variance, but they're both good to go.
Next I set up for the outer baffle, and again did a test on some foam board. Actually I wasn't 100% happy with the first cutout, so I did a second foam test, to try to keep the cutout a little tighter. I figured "I can always take more off, but I can't put it back on". So the foam baffle was just about perfect, and I moved on to cut the MDF.
Here's where the wobble came back to bite me. The cut looks good, but it's basically snug to the thick rubber gasket, and I can press fit the baffle holding itself up in place without any support. In this case I could have taken an extra 1/64" off, which would have been about perfect. Somehow I didn't take a pic of it in place, but here's my helper holding up the baffle.
Now I have to figure out how to shave sown the inside of the cutout a little bit. I already went at it by hand with some 80 grit, which took care of any little imperfections, but didn't make much difference in the overall fit. Is there an easy way to take a bit of material off? I don't want to buy any of those fancy sanding drum barrels, but I might be able to rig something up to chuck into the drill. I don't think either of my palm sanders will make much contact with the surface on this arc.
The other option is taking off that massive rubber gasket and just using some foam weather stripping tape or something around the inner baffle. Any thoughts on these gaskets? Are they recommended to use, or will something more generic work just as well?
The next thing I was blissfully unaware of is how tight my overall fit is, regarding the actual dimensions of the sub. I had planned for 20" width and 22" height. The width got reduced by about 1/8" during my panel cutting thanks to a sloppy cut (so I shaved down all the panels to match). When I fit the 2 baffles together, it's clear there's a gap at the sides.
The gap is small, actually a bit smaller than in the pic above, and it will be covered by where the side panels fit in, I just have to make sure there's room for T-nuts. I'll probably offset the mounting to account for that and hope it will be enough.
And that's about as far as I got over the weekend. Now I just need to decide if it would be better to trim down the inside of the outer baffles a bit or to remove the rubber gaskets from the drivers. Then I can figure out an assembly order and start gluing panels.
NOTE: I tried using the AVS gallery and directly inserting images into this post, instead of attaching them at the bottom. I always feel that it's better to see pics in order as the "story" unfolds, but MAN is that gallery a pain to use! It took me like 20 minutes just to upload the 24 images. I don't want to come back to this thread in 5 years and have all the images missing, which is the case with a lot of my old threads, so I'm avoiding external hosting. I might just go back to attaching after this lengthy undertaking though. The gallery interface is archaic and needlessly complicated, not to mention I could not find a batch upload for the life of me.