Pair of Jack 10s

[Philip Kelley]

OK, I hope I don't get in any trouble here. Warning for the faint-hearted; I have departed from Mr Fitzmaurice's plans occasionally. I built high end cabinetry professionally for over 20 years, and have a pretty decent "hobbyist" shop in my garage these days, so just because you see me do it doesn't mean that you should. I'm just trying to share ideas here, not chestbeat of mislead any other builders. Constructive criticism is welcomed. That said....

I decided to build the cabinet out of 12mm Italian Poplar ply. One of the neat things about living in Seattle is the ready availability of "exotic" materials. My goal is to build cabs as light as practical without going the composite route. That seems like the ultimate uber light solution, but would involve a whole new learning curve and a warm place to cure resins, which my garage ain't.

First step, cut out the baffles. I made a fairly accurate pattern out of scrap and routed the two baffles with that.




I decided to pre-assemble the throat duct and reflector panels into one assembly. I planned to round over the front edge of the assembly rather than the faceted design shown in the plans. I just liked the look, and hoped that it would not really effect the cabinet function. We'll see. First I added a small glue block to what would be the reflector panels, cut them to width, and trimmed the angle.





I first tried a jig-and-clamp assembly method which didn't work well. I then decided to dry mount the throat/reflector panels to baffle and then PL plus screws through the front edge.





Once the PL dried, I removed the screws holding the edges together, trimmed the assemblies to depth and rounded over the front edge. I smear the exposed plywood edges with PVA "wood glue" which seals and hardens the core laminates. Probably less important with Baltic Birch than the softer, more porous Poplar.

Next up: bracing. Since my 4x8 Poplar didn't cover all the parts, I supplemented that with some scrap material I had left over. Some 1/2" Baltic went into the Throat Ducts, and the braces are made of 1/4" Baltic Birch. Nice stuff- quite stiff and just a bit lighter than the 12 mm Poplar.

Horn Braces, with 1/4" dados in the Baffle, Throat Panels and Sides to receive them. The Throat assemblies have been glued to the Throat Panels at this point, but are still just tacked to the Baffles with a few screws.



Back Braces, also 1/4" BB, dadoed in, clamped and PL'd in place. I'm really liking that PL.





I wanted to pre paint the Throat, Baffles, and Top/Bottom parts before assembly, 'cause it looks like a pain to do neatly after the parts are all together. Primed, and Duratex'd.





Here is a detail of the Throat parts in stunning black Duratex. You'll see that I routed out the Throat Panels where the plans specify a 1" vent hole. Must's saved 3/4 of an ounce! I used an "overscribe" router bit for this cutout; basically a 1/4" flush trim bit with a 3/4" oversized bearing. 'Leaves a 1/4" overhang. I'll stuff the void with polyester batting.



And that's it up until this morning. More foolishness to come.

[Chris_Allen]

Very nice. We always like pictures.

[LelandCrooks]

Nice. If you have the tools, desire, and time to do it more elegantly why not. I like it.

[Philip Kelley]

Thanks. It's going to be fairly standard construction from this point on, except that I might fabricate some custom phase plugs out of EPS foam.

One thing I discovered, the first coat of Duratex I applied developed a (not so) nice crackle finish as it dried. The manufacturer says it can be applied without primer; from what I see so far, primer is definitely not helping, and I plan to skip it for the rest of the cabinet.

[LelandCrooks]

One thing I discovered, the first coat of Duratex I applied developed a (not so) nice crackle finish as it dried. The manufacturer says it can be applied without primer; from what I see so far, primer is definitely not helping, and I plan to skip it for the rest of the cabinet.

Humidity and temp more likely.

[Bill Fitzmaurice]

One thing I discovered, the first coat of Duratex I applied developed a (not so) nice crackle finish as it dried. The manufacturer says it can be applied without primer; from what I see so far, primer is definitely not helping, and I plan to skip it for the rest of the cabinet.

Humidity and temp more likely.

And/or too thick.

[Philip Kelley]

It did seem to go on very thick. Foam roller next time. Thanks.

[Bruce Weldy]

It did seem to go on very thick. Foam roller next time. Thanks.

Seriously consider the rollers that Leland sells. They are more porous and work really, really well. You might be able to find them locally, but they really make a difference.

[ian]

Leland, are your rollers the same as the ones from Acrytech?

[LelandCrooks]

Yes. They're the only place I've found that particular roller. It does work very well. I'm out.

[Tom O'Shea]

For an undramatic finish, I use yellow foam rollers from Home Despot. They have maybe 3/8" of "nap."

I'm thinking of ordering some gray poly foam rollers from Woodworker's Supply (http://www.woodworker.com). They have less "nap" and might could waste less duratex. The yellow foam soaks up a lot of paint that won't roll out easily, though you can squeeze most of it out before cleanup.

[Philip Kelley]

I'm going with some generic foam rollers from the local hardware store. They seem to work fine; not too thick, nice fine texture. I'll not bother with primer from now on, the duratex bonds to bare wood better than to primer, and of course, fills like crazy.

So here is what's been happening lately.

I made a quick and dirty "lathe" from a 1/2" drill, the mandrel from a wire brush wheel, a disk of plywood and good old double stick tape. So far so good as they say, more to come on the custom phase plug idea.



I glued up the Throat/Reflector subassemblies and the Top/Bottom panels. Once I had the parts together I saw that one of the units was racked- the top and bottom panels were twisted relative to each other. So I forced the sucker back into true, stacked the parts up, set a few heavy toolboxes on top to hold things in place and let it dry up overnight.





Hmmmm, that worked great. One of the Horn Panels on the unit I un-racked was shifted in the process so that the Throat/Horn joint was open and the Horn Panel was mis-aligned. I've torn apart mistakes before, and probably will again, so watch out.





Nothing that a bit of PL, my friend Bondo, and an extra hour or so of dinking around can't fix though.



As of this morning, they are fully assembled, Bondo'd, corners rounded and looking good. The two bare boxes weigh just under 28 pounds together, so each finished cabinet ought to come in around 25 pounds. For the record, one tube of PL was just enough for these two boxes, and that's being generous (messy) with the adhesive as well as having some minor re-do.

And for now Adieu.

[loudsubz]

Nice build.

[Chris_Allen]

I've used saws, drills and chisels in the workshop before but I am not entire sure how to use a bass neck. Do you use it to lever off the misplaced pieces of wood? Please explain.

[Philip Kelley]

It's got a bottle opener on the other end.