Just an observation but in your last photo it looks like the side piece has shrunk BUT the top piece hasn't, well at l can't see corresponding shrinkage marks on the side - bit difficult to be sure though. If that is the case and it is wood sourced and cut at the same time is there a clue there or is it just another bit of inconsistency? I assume btw that the very definite line along the joint and across the box is between two pieces of vinyl.And a typical eg of a troublesome one: from this photo sent to me, I counted joints along establishing the top seems to remain as is.. & its the side that drops down.
But I cannot factor out of course, that it's not the -whole- top's thickness, that's moved 'upward' instead. IE 21mm to 23mm.
It is making me go insane, let alone the customer. Thanks, SC
Hi Unicorn,maybe you need to have a look at the wood you are using then, in terms of how it is stored, sourced, seasoned, run a moisture meter over etc. Also maybe a sealing coat on the inside of the cabinet might help to minimise movement. I'd do a whole bunch of test pieces and see what makes things better worse
Pine will always have a movement problem - it's a soft porous wood that can absorb and release moisture. This is particularly so because of the open pore structure and pine oils are not compatible with water.
I have done several very fine finger joints ( 4 mm ) in relatively soft woods ( well seasoned ).
I always cut the finger at least 2 mm deeper than the base wood - and ONLY use epoxy glue. Why ? - NO moisture introduced into the join and the joint strength is much greater.
Once the epoxy is cured, just sand off the excess.
Particularly with soft woods, the stability of the final product will depend on sealing out moisture - either by varnish, oils, or waxing
I'm adamant it would, but I cannot sell my boxes if hardwood, as the expense to make them is prohibitive, the customer doesn't want hardwood, & I cannot source hardwood out here anyway.. without travelling huge distances that is. It'd add msybe £25 to each box. I make no profit as it is on the pine one.A hard wood would move less?
Understood thanks. Thing is out here, it's not only wild, but very moisture heavy too.I agree with TheUnicorn- it's most likely that your timber isn't dry enough when you get it. If you can afford to, it would be a good idea to get a moisture meter and check a new bit of timber against one that's been in your workshop for a while.
If they are covered in vinyl you can make them of any old rubbish as long as it does the job. I strongly recommend the simple T&G joint plus rubbed glue blocks I've described above.I'm adamant it would, but I cannot sell my boxes if hardwood, as the expense to make them is prohibitive, the customer doesn't want hardwood, & I cannot source hardwood out here anyway.. without travelling huge distances that is. It'd add msybe £25 to each box. I make no profit as it is on the pine one.
Unfortunately an amp cabinet, needs to be both super-strong in the join type, & have no internal extra wood, as amp hardware goes up to the very inside edges. And 'fingerjointed' is just expected as it follows amp cabinet custom going back to late 1940's too. Pine is also inherrant to the sonic signature. And light enough. And affordable - just, still-. No other alternative alas.Wrong joint for the job?
I would have tongue and grooved it, with glue blocks on the inside. Would leave just one line visible and OK even if showing through.
Also a lot easier - those DTs are over the top really.
P.S. Wrong material for the job too. Ply or MDF?
The wood is going to make no difference to an amp. Maybe it would for a speaker.Unfortunately an amp cabinet, needs to be both super-strong in the join type, & have no internal extra wood, as amp hardware goes up to the very inside edges. And 'fingerjointed' is just expected as it follows amp cabinet custom going back to late 1940's too. Pine is also inherrant to the sonic signature. And light enough. And affordable - just, still-. No other alternative alas.
If they have to be made from softwood and you want to finger joint the corners you could try Accoya which is treated Radiata Pine, it won't shrink but is expensive and a bit brittle in use.
Think I'd be mitring them.
You don't need a fancy joint at all, as it's covered and out of sight.
Here's a pic of a T&G box joint. I've made hundreds of boxes like this, over the top of a TS.
View attachment 138687
A rebate would be even simpler to machine but harder to join as it would need careful clamping or pinning.
Either way rubbed glued blocks would add strength and very easy to do.
You flood each side with PVA glue, press and rub it into position and let go after a few seconds. That's enough to hold them in place as the glue goes off. They are sometimes shown drilled and screwed but this isn't necessary.
They are widely used in boxes like yours, or under stair treads and all sorts of cabinets.
View attachment 138690
Enter your email address to join:
Register today and take advantage of membership benefits.
Enter your email address to join: