Tapering MDF Panel

[Paul Canaris]

What approach would you use to tapering an MDF panel, if you did not have something exotic like a CNC.

The panel is going to be about seven foot long, and about two foot wide. It will need to end tapering from its 1.25” center thickness to about .75” at the edge. It needs to end up as a smooth ark.

I need to make four of these panels.

How would you approach doing this?

[Rob Wright]

Paul - is the taper over the long 7-ft length or the 2 ft width? If it was over the 2-ft width - a sled/jig setup for a router to rest in with that profile moved along that profile, just move it down over the length a half a bit width at a time? I have seen jigs like this for carving out seats.

- R

[Dale Lesak]

Is this going to be a curved panel the length of the panel?

[Tyler Purcell]

Perhaps a long "ramp" of sorts for a router to slide on. The ramp could be adjustable, and sit on the sides of the strips. On one end, the sled for the router would be propped up to 1.25" and the other end would slope to .75".


I drew an extremely bad sketch for you to explain what I mean. The MDF panel is the orange-brown, the jig is the grey matter. A router would slide along this jig to surface with a large upspiral bit, for example. The left side is .75" tall, the right 1.25".

[Jamie Buxton]

It sounds like your idea is to start with a thick blank and remove a bunch of it. How 'bout instead building it up with two sheets of MDF and wedges between them? For instance, start with two sheets of 3/8" thick MDF. Cut wedges of anything convenient which are zero thickness at one end and 1/2" thick at the other. Insert the wedges between the two sheets of MDF, and glue it all together. You get an object which is 3/4" thick at one end and 1 1/4" thick at the other. You also get the nice smooth factory faces on the MDF.

[Tim Sproul]

How would you approach doing this?

I'd bend a 1/4 inch board. Use a 1/2 inch board as the substrate and lay a stip down the midde to get 1 1/2 thickness overall....and lay subsequently thinner strips as you get to the end to get 3/4 thickness eventually.

Use a vacuum bag to get good clamping over the entire piece.

[Paul Canaris]

Paul - is the taper over the long 7-ft length or the 2 ft width? If it was over the 2-ft width - a sled/jig setup for a router to rest in with that profile moved along that profile, just move it down over the length a half a bit width at a time? I have seen jigs like this for carving out seats.

- R

It's over the two foot dimension

[Paul Canaris]

I'd bend a 1/4 inch board. Use a 1/2 inch board as the substrate and lay a stip down the midde to get 1 1/2 thickness overall....and lay subsequently thinner strips as you get to the end to get 3/4 thickness eventually.

Use a vacuum bag to get good clamping over the entire piece.

Would work normally, but this is for a speaker enclosure so the sides need to be very solid, so it will all need to be solid.

[Jamie Buxton]

Would work normally, but this is for a speaker enclosure so the sides need to be very solid, so it will all need to be solid.

Folks used to build speaker enclosures with hollow walls and then pour sand in them. Now that is high-density, non-reverberant stuff.

[Jamie Buxton]

Paul, I'm getting the feeling that we don't really understand what you're building. Folks are proposing all sorts of tapering schemes that don't do the same thing. Could you post a sketch of what you're trying to do?

[Paul Canaris]

This will be a seven foot tall, two foot dep rectangle, the sides will be curved from front to back. So the sides will have a rounded appearance.

[Jamie Buxton]

This will be a seven foot tall, two foot dep rectangle, the sides will be curved from front to back. So the sides will have a rounded appearance.

Something like this?

[Paul Canaris]

Something like this?

You got it buddy!!!!

[Jim Kountz]

How bout just building the box square, then make some curved cleats and space them out evenly down the entire edge. Then lay on a nice easy to bend 1/4" sheet of ply. Rout or sand the edges flush and you have your desired shape without any tapering to do at all. Kind of a box in a box but not if that makes any sense.

[Paul Canaris]

How bout just building the box square, then make some curved cleats and space them out evenly down the entire edge. Then lay on a nice easy to bend 1/4" sheet of ply. Rout or sand the edges flush and you have your desired shape without any tapering to do at all. Kind of a box in a box but not if that makes any sense.

Resonance would be a serious issue, otherwise that would be a great approach.