Cabinet Builders: How to apply 6mm timber to MDF with Mitred corners (1 Viewer)

[Jonathan M]

Another question in the endless pursuit of attractive cabinets.

I'm building smallish satellites from 18mm MDF, and am considering covering them with 6mm thick timber instead of veneer. (Due to the high cost of Veneer in New Zealand, and because I have heaps of recycled native timber lying around)

My current plan is to apply the timber for the back first, flush with the MDF box, then the sides, top and bottom, with the grain all the same way (Parallel with the front baffle) and the Front last (Will probably be thicker at around 12mm)

I'm wanting as little end grain as possible, and so am wanting to Mitre cut the joins between the top, bottom and sides. My current plan is as follows:

1. Apply back, flush trim to MDF.
2. Apply side 1, mitre trim to top and bottom.
3. Pre-mitre side 1 end of the top, glue to face, and mitre trim to side 2.
4. Pre-mitre top end of the side 2, glue to face, and mitre trim to bottom.
5. Pre-cut and mitre the bottom, and glue in place.

The front will then just be glued flush, the only end grain on the front/top, front/bottom edges, which will be rounded over.

Any comments as to the viability of this?

 

[Hank Frankenberg]

Jonathan, #1 concern would be that the lumber is dry so that it will move as little as possible after attachment. Lumber will move, but as this is about 1/4" and the lengths will be short, you should be okay. Miters are very difficult to get right, as a degree off can be visible, but if you're experienced and have an accurate 45 degree blade seting and a very sharp blade, go for it. Why not attach the rear, then cut, fit, trim, tweak the other panels before attaching them? Just in case you make a mistake on a panel after it's glued in place.

I'm surprised that veneer is so expensive there. Isn't there a lot of cabinetry done with native woods in Austraila? I'd think they would make veneer and you could import it.

 

[Jonathan M]

Thanks for the reply, Hank.

Yes, the timber is dry as a bone. It's all out of an old warehouse that was torn down, and I've had most of it in dry storage in the top of the garage for a few years. It's all different thicknesses, but I have access to a jointer/buzzer so that's no problem to get it all down to around 6mm - I figured that size is still easy to work with, but thin enough not to cause too many problems.

As for the Mitre'ing, I'm planning to do it with the router.
I've got a router that has an attachment to it's base which basically makes 1/2 the base around 1/2" thicker than the rest, giving a 1/2" nib centred on the centre of any bit in the router. I fit a 45 degree V bit to the router, and run it along the overhanging timber, so that the nib runs along the timber. The 45 degree bit then cuts the overhang off at the appropriate angle. I haven't tested this method out yet, but in theory it should work. I'll probably try some practise runs in the next few days to see whether it's doable. The main reason I'll be mitre'ing while the panels are glued on is that the panels themselves will be laminated (The timber ranges from 3" to 5" wide)

I may yet just do everything with butt joints - It'll certainly make everything easier!

As for Veneer prices in NZ, most furniture is built solid here (out of pine etc.) and the better stuff is usually built out of recycled timber. You can get pre-veneered sheets of MDF, but getting the actual veneer (Especially real wood veneers) is difficult - and because it's not in demand, is expensive. (Around US$100 a sheet - not fancy stuff, either)

 

[Pete Mazz]

Hank pretty much covered the pitfalls of wood over MDF.

I've got a router that has an attachment to it's base which basically makes 1/2 the base around 1/2" thicker than the rest, giving a 1/2" nib centred on the centre of any bit in the router. I fit a 45 degree V bit to the router, and run it along the overhanging timber, so that the nib runs along the timber. The 45 degree bit then cuts the overhang off at the appropriate angle.

Interesting concept. You may get in trouble when you're at the end of the cut and the first half of the router base leaves the working edge. Then you'll be left with just the back half of the base still in contact with an edge that's already been machined. Not sure if it'll work. You may be better off with a carefully set up straight edge.
I think I would rather see you plane the wood down to ~1/8" and just flush trim and use a butt joint. Would go a lot faster and less chance of FUBARS.
Pete

 

[Jonathan M]

I think I would rather see you plane the wood down to ~1/8" and just flush trim and use a butt joint. Would go a lot faster and less chance of FUBARS.

I must admit that I am tending this way at present. I'm going to give it a go on a smallish practise piece and see if it's doable. Will probably end up with butted joints, as they are MUCH easier and faster - plus rounding over (with a small radius) is doable then. I've done my sub box like this, and it looks pretty good at the moment (Yet to finish it)
Thanks for the feedback, guys! Pics will be forthcoming