Building a 2x12 from solid wood

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NippleWrestler
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Building a 2x12 from solid wood

Post by NippleWrestler »

Howdy do,

I bought some macrocarpa for an amp shell. I had enough for a 2x12 cab roughly sized to Marshall 1936 dimensions (they're very big), except this one is 2/3 open back and not quite as deep.

So external dimensions are 770 x 550 x 300mm. Internal is that - 60mm (30mm thick macro here) along height and width. Still plenty darn big. I opted for an open back because 300mm excluding baffle and battens isn't really deep enough for big bassy thump, and I've already got a Rectifier 2x12 which takes care of all that. Hopefully this will be warmer, more open, not as beamed in the sound and fill a room a bit nicer.

I'm working with a jigsaw and an orbital sander, along with a power drill, that's it.

So I marked out the wood, cut it with the jigsaw, then glued and screwed the joints. I'm using 5 x 100mm stainless screws at each join along with Titebond II. These screws are immense. I can stand on this thing and there's no wobble (i'm 100kg). Here it is as a box.

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Then we'll skip a day because nothing exciting happens save for cutting and adding the pine battens (18x18), caulking all the joints so it's airtight, and painting the inside black.

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That white splodge is silicone caulk. The paint has a hard time covering it. It's on the inside because the macro does have some knots and twists that I personally like the look of, but don't want them leaking air from the sides, so I sealed them from the inside to make the walls airtight but to keep the knotty appearance externally. Worth mentioning that only a few of them go through the entire way.

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Then sanding begins. This stuff has been outside for about 3 years so it's pretty gnarly. It took 5 80 grit discs to get it looking nice and leveled off.

It's full of sawdust here.

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Here are the back baffle pieces, one for the top and one for the bottom with a 100mm gap between. This is 18mm AB grade ply.

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And this will be the front baffle, this is 19mm marine ply. It's the top grade plywood, void-free throughout and heavy as all hell but since it'll have 2 12" speakers hanging from it, it needs to be tough.

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And so far that's it. THe speakers are a 1982 Celestion G12M 70, and a 1974 Celestion T2324 with the red frame and a 2" magnet on the back (!). Awesome combo. Massive mids from the red Celestion, and 80s hair metal sounds from the G12 70.

The cab will be finished in clear poly, there's a red speaker grille coming and I've got white piping for the edges. I'll paint the baffle black beforehand so the red grille goes blood red as oppose to fire engine red and I've got some massive castors for the underside too. Will update as and when!

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Re: Building a 2x12 from solid wood

Post by Reg18 »

This looks great!

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Re: Building a 2x12 from solid wood

Post by Jay »

Very nice. I like "furniture" cabs.

That macrocarpa came up beautifully. I trust you enjoyed the smell of it too :D
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Re: Building a 2x12 from solid wood

Post by Spykerwolf »

Looks pretty good

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Re: Building a 2x12 from solid wood

Post by GrantB »

Looks great. I assume you're building it in its final resting place? Looks heavy as!
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Re: Building a 2x12 from solid wood

Post by Mini Forklift »

Awesome, will be following along. Good luck!

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Re: Building a 2x12 from solid wood

Post by NippleWrestler »

Cut the baffle with a jigsaw. Man this stuff is hard as hell. 19mm marine ply is no joke.

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Marked out the spacing of the speakers via the wonders of a ruler and a pen.

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Then I took the back baffle

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And took this guy

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Drilled this

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which seats the jack cup, like this

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bam.

I ordered the tee nuts and corresponding hex socket screws last week from Partz Online. They said they turned up but nothing has arrived and I think they are talking out of their bum cracks. The whole plan was to situate the nuts (arf arf) and drill the speaker holes, then I can paint it up, ready for attaching the grille cloth. This puts my schedule out of whack and pushes the project back.

But because I was intrigued/impatient I made a bad mockup.

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Re: Building a 2x12 from solid wood

Post by NippleWrestler »

GrantB wrote:Looks great. I assume you're building it in its final resting place? Looks heavy as!
Macrocarpa isn't heavy at all, way lighter than AA plywood used in other top-tier cabs. And there will be wheels for this one so it should be rather portable.

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Re: Building a 2x12 from solid wood

Post by Bg »

looking good :) you can get tee nuts at mitre10! I have a boxfull here though, I can drop some in the post or something if the others don't turn up
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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Re: Building a 2x12 from solid wood

Post by StrummersOfThunder »

Looking great !!!!

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Re: Building a 2x12 from solid wood

Post by NippleWrestler »

They only sell m5, I need m6.

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Re: Building a 2x12 from solid wood

Post by Bg »

NippleWrestler wrote:They only sell m5, I need m6.
as the missus says, its that extra millimetre that counts... :crazy:
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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Re: Building a 2x12 from solid wood

Post by NippleWrestler »

Progress. It looks like tee nuts, that finally arrived after my neighbour "opened the wrong mailbox" and took them, yet left everything else in there. Whatever. They're here now.

I marked out the circles for the speakers, situated the speaker then drilled a 6mm hole to house the M6 tee nut, using the speaker's mounting holes as a guide. With the 6mm hole drilled in the right place, it was then a matter of lining up the central shaft of the tee and hammering it in place - slowly at first until the prongs grip, then just go for it.

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The circle is a 10.5" radius. I drew around a 10.5" frying pan which is how I know.

Inside that circle at every compass point I drilled a 10mm hole. Why? That's for the jigsaw blade to turn around in if I need it so I can realign the direction of the cut to keep it as circular as I can.

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Test run with the 1982 M70 in place:

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It fits! It's stable.This plywood is immense. I love it.

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I'm using stainless M6 hex socket bolts to hold the speakers in place, they look like this and tighten with a 4mm allen key.

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Jigsaw the other hole, mess up the alignment slightly and it looks like this:

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I wonder if I can use these plywood discs for anything:

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In situ.

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Grille cloth is on the way so next job is to sand down the cab, smooth out the baffle, paint the baffle black, then I can add the grille cloth and the piping. Then it's just finishing and wiring. Watch this space.

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Re: Building a 2x12 from solid wood

Post by Bg »

don't forget to paint the edges And the T nuts, else you'll have shiny t-nuts showing through your grille cloth ;) I've never bothered hammering the tee nuts in place, they tighten up as you tighten the bolts.
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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Re: Building a 2x12 from solid wood

Post by Bg »

oh hang on, you put the T nuts on the inside? mmmmm'kay. Unconventional :)
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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