How can I make a massive roundover? 60mm radius?

Someone has asked me if I'd be able to do this for them, its a 128mm thick panel, needs a roundover on both sides, so about 60mm radius.

How would/could I go about doing this?

One MASSIVE issue, is that its currently installed in a car, can't be removed, and has to all be done vertically.....

Any ideas? he wants it done in the MDF, whereas I suggested PVC pipe (maybe filled with expanding foam)

thanks! :shhh:
its to flare the port on a subwoofer box, but its the entire thickness of the baffle.

My suggestion was to remove as much material as possible with a jigsaw, then belt sand and flap disc it.

However, I'm wondering if it would be easier, and neater, to remove as much as possible with a jigsaw, without worrying too much about how neat it is, then make a template to use bog to build the level back up!


2013-03-17 11:00 pm
Line the interior of the car with auto painting plastic masking paper. Tape it down everywhere, including the headliner. Wear proper eye protection and a respirator. Also, buy a cheap tyvek painters suit. When you're ready to remove the plastic and dust, spray it down with water in a windex spray bottle.

The rounding over can be accomplished with 3M 24 grit paper on a long board, with stepping up through the grits as you get close to the right contour. As you get close, switch to a soft rubber backing for the paper. I think it will go faster than you think on MDF.

You can get your materials at any body shop supply wholesaler.
a bevel is nearly as good, and you can do it with a lot less dust with simple tools (circ saw, CAREFULLY). DO mask the vehicle if you ever want the dust out.
Actually, a bevel is better than a spherical radius.
With a full radius on the port there is separation of flow before the flow gets more than half way around the radius.
Just like with exhaust systems, angle of more than ~22 degrees causes separation of flow from the surface of the expanding flare.