Ductape over the outside of the bend will strengthen it enough for bending.
You might damage it a bit while peeling the ductape off...Might need sanding.
You might damage it a bit while peeling the ductape off...Might need sanding.
Since MDF is nothing but adhesive bonded particles I would think that this would be a fairly poor material to bend no matter the number of kerf cuts....
You should have a look through here 😉
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Although my kerf is already done now... so arguing that bending MDF won't work very well, or will crack, or offering other ideas probably wasn't needed 😛
an added a veneer layer before you attempt this.
I was about to post this little nugget but thought I should fully read all the suggestions, considering the level of knowledge of the posters. 🙂
You might also want to consider some glue in the cuts. Use tape on the ends to control the bleed-out.
I would think that if you didn't put something like glue, or filled polyester, aka bondo, or some filled epoxy or something in the kerf that eventually the mdf is going to crack in the bends from the vibration of the enclosure if you are going to turn it up. If you used wood glue with no filler you are going to have to fill the cracks many times and it will take forever for that much glue to dry. It will shrink back and you will have to fill it again.
The kerfs do not need to be filled with glue. Adding it before bending will assist ever so slightly in the softening of the uncut part and add a bit of strength, it will also be absorbed very quickly due to the nature of MDF, no need to worry about dry time. 🙂
I guess it is just me then, I fill the entire cut when I cut a kerf like that even with ply. I want it solid.
You got it, need to remove more than what you have for 90degrees. You could go back and make 1/2 depth cuts on existing slots to widen the curf on the inside radius. Kind of a poorman's taper.
Make sure you practice on a few pieces of scrap. Wont get too many flexes out of a piece of mdf before it breaks.
edit - I was a little late and didn't see the remaining posts. Nice Work.
I have also used "Bondo" to fill in the curf before bending. It squeezes out and can be smoothed before it is solid. I have since switched to epoxy and micro ballon filler. Soaks into the mdf and makes it quite strong
Make sure you practice on a few pieces of scrap. Wont get too many flexes out of a piece of mdf before it breaks.
edit - I was a little late and didn't see the remaining posts. Nice Work.
I have also used "Bondo" to fill in the curf before bending. It squeezes out and can be smoothed before it is solid. I have since switched to epoxy and micro ballon filler. Soaks into the mdf and makes it quite strong
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I think I could have gotten away with the number of cuts I originally did, I only ended up adding one more 😉 But now I don't know the radius, or how round it even is, and I need to add the brace to the port...
Practice? I didn't practice anything! lol, and this is a box I'm being paid to make... this WAS the practice!
Practice? I didn't practice anything! lol, and this is a box I'm being paid to make... this WAS the practice!

Let me rephrase , i used to get a 90deg HDF radius from my hardware supplier, i would think your local funiture hardware supplier would have ..
Like this :
MDF Prefit L Quarter Round: 4" Radius, 3/4" x 96"
Regards ...
Like this :
MDF Prefit L Quarter Round: 4" Radius, 3/4" x 96"
Regards ...
I cant exactly affix that to the box very securely though, unless I also put a 45 degree piece inside the box.
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