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

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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:
Tell your buddy next time he needs to do the fabrication BEFORE the installation! It sounds like a subwoofer this radius job essential to function or merely cosmetic? DSP-Geek is right, this will generate so much dust and shavings that he'll never get the inside of the car clean again. You need to work on a Plan B!
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!
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.

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