Building a lightweight 1x12 cab

[Grant]

I am fundamentally incapable of not overcomplicating everything.



color key:
sand: cheap pine ply
tan dowels: poplar
tan veneers: super cheap Home Depot 1/8" generic hardwood ply. inner veneers not pictured
pink: extruded polystyrene insulation foam sheet (Foamular)

speaker (neodymium): Jensen Jet Tornado 80

It's more or less assembled at this point, pictures to come.

todo:
- make speaker and back baffles
- apply wood filler to unwanted gaps/holes
- rout roundovers (1/2")
- paint
- mount speaker, baffles, handle, corners

[Grant]

Make them walls:

Layer 1/2" ply together, CNC out the middle:


Cut foam from 2'x2'x1" sheets, also with CNC:


Combine?:



As with the top:



As with the not-at-all-ambiguously-marked bottom:


Add


Done.


Wait 24 hours for adhesive to cure.

[Grant]

Continue them walls:

Plane sandwich parts to final thickness:


Forget to take pics of anything but the sides.

TEST FIT THEM MOTHERFUCKERS:




Note the dovetails. The dovetails were a mistake. More on that later.

[Grant]

Summon a skeleton:


hail satan.

[Grant]

Neglect to take pics when gluing the veneers.

Test fit like there's no tomorrow:


Give blood sacrifice:


HAIL SATAN

[Grant]

On dovetails in plywood, and why they were a bad idea.



The dovetails were added to the design when I still planned to use solid wood. When I made the switch to plywood, I did not reassess their inclusion.

I assume there are ways to do this correctly. I'm just learning CNC stuff, and doing so with dulled communal endmills. I ended up with lots of tear out:



This was compounded by the fact that I left entirely too much to hand-finishing. I didn't take full advantage of the CNC's capabilities, didn't design with them in mind, so I ended up sloppily bashing/sanding/cutting things to fit. So it goes!

[Grant]

Pre glue:



Design flaws and inexpert hand-finishing left gaps, and wood glue is a very poor gap filler, so I opted to use polyurethane construction adhesive. Polyurethane construction adhesive expands when it cures, moreso than I anticipated. I don't have any pics of the post-cure state of the cab, but a mm or two have been added to the width and height due to the expansion between the walls and the skeleton. S'all good. Should be easy to avoid next time.

[Fakir Mustache]

Wow, that's a lot more complicated than most manufactured cabs.

[paul_]

So fucking cool

[Grant]

Progress!

Routed all outer edges with a 1/2" roundover bit:


Ridiculous tear-out of the cheap plywood veneer:


Short recap: design flaws resulted in joints that wouldn't work with wood glue. I chose to use polyurethane construction adhesive for its gap-filling properties. Turns out it's easy to overdo the glue when you don't know what you're doing, and that gap-filling glues can expand gaps.

Gap at corners:


Gap between wall, veneer.


Welp!

I set about closing inner gaps with caulk and outer gaps with wood filler. I had never used caulk before, and decided to skip the "tape what you don't want caulked" step.

Results were predictable:




Looks like someone murdered the Stay Puft Marshmallow Man.

Wood filler on the corners/etc. Bondo would have been a better choice, I think.





Looking good. Looking real good.

[Grant]

Things are ugly. Let's try to make them less ugly, a little, maybe.

Go back over the edges with the roundover bit:


Pause for selfie with the nerdpace's mantra:


Spend untold hours sanding, scraping, chiseling, etc.:


Hail Satan.

[Grant]

That looks way better than it should. Onward!

Speaker baffle:

Wood filler.

Back baffle:

Wood filler.

Handle:


Note that the screw holes don't line up. I had used the measurements of another handle, apparently. Welp.

Next update: painting. God help us.

[Grant]

With regards to the handle:

This is the thing I designed/cut/drilled for:


This is the thing I bought:



I've used the opportunity to start learning Fusion. I intend to print it at the local nerdspace.

[Doog]

Amazing!