Translam Subwoofers with 18" Passive Radiators - The Jedi Mind Tricks

[wogg]

Dang... I'd be pacing back and forth in the shop for hours mumbling obscenities. You might have better luck with spreader clamps if you release the cross braces first, then re-brace to hold the tension. Don't take my word for it though, I lack the skills and experience to get that far.

[Kevin K.]

Cut your dowel rods loose. I think you'll be surprised how easy it is to push that wall back out once the dowels are loose. Yea, it sucks, you'll have to replace them which mean clearing the holes back out to install the new ones. If you don't have two framing squares, you might need two to fix this. Clamp the squares to each wall before you epoxy the new dowels in to make sure both are square. You could also put the dowels for the top in and set in on dry to help alignment. Good luck!

[KEtheredge87]

Dang... I'd be pacing back and forth in the shop for hours mumbling obscenities.

That's exactly what's going on in one part of my brain... the part that exists beyond the "keep calm and figure it out" part!

Cut your dowel rods loose. ... If you don't have two framing squares, you might need two to fix this.

Thanks Kevin and Wogg for the suggestions! I'm slowly accepting the fact I'll need to cut the dowel rods out. If it will save the project, then I'll make it work. If I had an air compressor powerful enough to run a small die grinder that would also make clearing out those dowel holes much easier. I'm not sure my little bostitch can put out enough flow to really make that happen!

On the framing squares... do you mean the right angle jobbies that are just flat steel? I'm having trouble imagining how to clamp that against the wall. Maybe I'm just being dense at the moment.

[marvin]

Maybe these glue up squares from Rockler will do the trick.

https://www.rockler.com/clamp-it-assembly-square

[jhollander]

What Kevin said but I'd only focus on getting the joint between the top and bottom section right. Being square is not that important imo.

[Kevin K.]

After thinking about it a little Keith, I don't think you would need to clamp the squares. Maybe just cut a board to length that anchors at the bottom of the left wall and anchors at the top of the right wall to push it out and hold it in place while the glue for the new dowel rods cures. As for cutting the dowel rods and clearing them out, a small hand saw should allow you to cut them pretty close to the walls and a butterfly bit should work to clear the hole out for the next ones.

[Kevin K.]

Another option for squaring the walls would be to rip a sheet of ply the width of the opening for the front baffle and place it in there until the dowel glue cures. Maybe front and rear on the baffles to make sure.

[KEtheredge87]

Kevin, Marvin, John, Wogg... thanks so much for the good ideas. I cut the dowel rods and was pleasantly surprised at how little force was required to adjust the walls. I was able to place the first layer of the top section on the walls as a guide while adjusting the front and back with clamps arranged as spreaders. I think this will work out OK, but I'm going to glue my top layers together separately from the base and walls of this cabinet. That way I'm not spreading the cabinet out while trying to clamp vertically, it just seems like a lot going on. I'll work through the top curve cutting, then spread the walls, replace the dowels, and glue the top. I like Kevin's last comment as well, about putting a placeholder plywood baffle in the front and back to hold things while the dowel rod glue dries. I may try that if I can convince myself the opening is square enough. I still think I'm going to need a trim with a router to address that.



I hadn't considered using a spade bit to clear out the holes after hand sawing them close... that's another "keep it simple" idea that should work nicely. I was sitting here hatching a plan to buy some rotary rasps that I could dremel out the dowel pocket, but the spade bit should work just as well.

One final note that I intended to share before going into problem solving mode.... I ordered a quart size kit of TotalBoat 5:1 Epoxy to coat the insides of these cabinets like Wolf and I were discussing earlier in the thread. $50 across two translam subwoofer cabinets seems like pretty cheap delamination insurance, so I figured it's worth a go. Plenty of reviews on both Amazon and Jamestown Distributors (think PE for boats I guess) that said this stuff was just as effective at construction style work as West System, just at lower prices.

[Kevin K.]

Glad to hear you'll be able to salvage it Keith. Don't get discouraged, sometimes these things happen. Unless you're doing this stuff for a living, there will be learning curves from every project for a good while.

Without a doubt, these are going to be some FANTASTIC looking subs, keep up the good work!

[Wolf]

Don't cut your dowels out!! Just shim them with pieces and reglue. It'll be just fine, and they are already there.
Maybe a wrap of tape while the new glue sets?
Later,
Wolf

[marvin]

Excellent idea, Ben! It won't look as nice from the inside but you won't notice from the outside. If you cut the dowels right at the wall and insert the shim there it will look like a mounting base. You can even make the shims from dowel stock to make them less obvious.

[scottvalentin]

Good thinking on the epoxy. A guy over at HTGuide did some really large 4-way speakers that were a translam construction. He didn't seal the inside and his ply layers started delaminating (the actual plywood, not his glued layers) and he ended up with some large cracks. Epoxy on the inside to seal that ply is a good call from what I can gather! If you are curious, the username was Cochinada, and his thread was called My First Project is a 4-way Speaker. It's a long thread, but just in the last page or two of posts is the cracking.

[KEtheredge87]

Don't cut your dowels out!! Just shim them with pieces and reglue. It'll be just fine, and they are already there.
Maybe a wrap of tape while the new glue sets?

...You can even make the shims from dowel stock to make them less obvious.

Good thinking on the epoxy...

Thanks guys! I appreciate the feedback as always. Ben, I like the idea of salvaging the dowels that are already there. I also like Marvin's idea of doing so with dowel shim stock. I happen to have plenty of leftover dowel and could easily do this on the bandsaw. I think in addition to wood glue between the shim/dowel bits, I'll try a wrap of this FiberFix Plumber's Tape on the dowels after gluing to add one more layer of reinforcement.

I hope the epoxy pans out like I expect it to. I did see some of the other photos that were referenced in the HTGuide article. Those little scrapers seem like an ideal tool for that job too. I'm hoping that a few thousandths of an inch will be all the coverage I need to hold things together. I'm not planning to wet out any fiberglass on the walls, but I may change my mind there. I'd have to buy some, but I'd prefer not to add much material to the inside that would detract from my overall volume. I'm probably splitting hairs at this point though. I did a pretty thorough job trying to estimate PR and Active driver volume displacement by physical displacement of water in a bath, and I included the dowels in my numbers already. If anyone more experienced in that kind of tradeoff can weigh in, I'm all ears.

I'll keep working toward completion of these boxes and see if I run into any more interesting challenges to surmount!

[KEtheredge87]

Hi Guys,

While waiting for wood glue to dry, I'll give you all an update. I finished gluing the top pieces together for the second box, and drilled out decorative holes for walnut dowels on top of the first box. I made sure to put a solid amount of walnut dowel into each hole, so I get a cool elliptical shape when I cut the tops with a router.

My second box still needs a proper fix on the dowel rod cross braces that I had to cut, but I didn't feel comfortable making that repair until my top was totally glued together. This way I'm sure that the top and bottom will meet up nicely, then I can fix the dowels. This should be a project for tomorrow.

I also put together my little marking method for locating the vertical dowel holes on the ceiling. I used a scrap section of dowel rod with a blind nail in the center of it. The dowel length is just short of the ceiling with the nail included, so I dropped the dowel into the bottom hole. used a speed square and adjustable square to line things up as best I could, then pushed the dowel straight up into the ceiling. I only had ~1/4" or less between the nail and the ceiling, so I shouldn't have ended up too far off axis. I can go back with a forstner bit before cutting the top curve and create a pocket for the top of the dowel to be epoxied into place.

Once these items are taken care of, I can focus on making a quick radius cutting jig for the top. Won't be too much longer and I'll be truing things up for some baffles!

[KEtheredge87]

Good afternoon, everyone!

I have completed my repair of the dowel braces in the second subwoofer cabinet, and I'm currently waiting for that epoxy to cure up such that the dowels will handle the load without moving on me. I want to thank everyone for their input and suggestions on how to fix this leaning issue I was having. Ultimately, I decided to completely remove the original dowels and install new ones while the cabinet was propped open to the right spot. This was a lot easier than I was envisioning, and didn't cost much except for my time. I used a flush trim hand saw to cut the dowels out against the walls, then used my 1" forstner bit in my drill to carve out the remaining bit of dowel. From there, a little dremel sanding to clean out as much old epoxy as I could, and we were back in business.

I improved my epoxy setting method over the first go-round, by putting gravity to work for me. I layed the cabinet on its side and shimmed it up such that the dowel pockets were level, then poured epoxy into the cavities and set the dowel in place. This way I was guaranteed to get epoxy coverage over all the dowel AND have enough to fill the corners of my square-ish pockets. I actually feel better about the strength of these mounts than I did for the first ones where I installed them in a horizontal position (dealing with epoxy trying to flow out of the corners and down the box!)

I made sure to check the corners of the box for squareness before pouring epoxy, and I'm satisfied with the result. It's certainly better than where I was before, and I do not expect to have major issues setting a baffle into place. I'm expecting only minor finagling to get the baffles in... glued up with PL platinum, then dressed up with a guitar binding inlay.

At this point I only need to mark and cut the ceiling holes for cabinet top #2, and cut the vertical dowels to match. Then I have all the detail woodworking done so I can focus on cutting the top. I feel like I've been saying "soon I'll cut the top" for a few days now... time flies when you're fixing problems!



Also worth noting... I think these cabinets look cool on their sides too! Sorta like a concert monitor speaker for the band. Feet would have been a bigger challenge though.