Router bowl burning and sanding.

[nblain]

Apologies for these rather basic questions, but I'm very new to all this. (I was going to attach pictures, but I'm not allowed to, maybe because I'm new to the forum?)

I've being trying to make some small bowls using a Makita trim router. I've overcome most issues by making jigs and the like, but a couple of problems remain, for which I would be grateful for any advice.

I'm taking most of the middle of the bowl out using a forstner bit on a drill press, then using a bowl bit in the router to get to the final depth. No matter how hard I try, I keep getting burn marks even though I'm trying to make light cuts.

I find it very difficult to get a perfectly flat bottom on the inside of the bowl. I'm using a sanding disc mounted on a foam base on a drill press, and offering the work piece up to it, but no matter how level I keep the work piece there always seem to be very slight undulations at the bottom of the bowl.

TIA
Nigel

[nblain]

Can now add some pics.IMG_6114.jpgIMG_6115.jpg

[Treecycle]

Burning is usually caused by either blunt router bits or the speed of moving over the surface is too slow. Endgrain is the worst for burning and requires even faster movement. You will see from your photo that the endgrain has the most burning.
Using a flat sanding pad makes it very difficult to not dig in and therefore create grooves. I can only suggest using a very light touch and fairly fine sandpaper, but keep the workpiece moving quickly under the pad.

[nblain]

Many thanks for your reply. I would hope that the bit isn't blunt, as hardly used and I made a point of getting a quality one. I'll have to try faster passes next time around. Interestingly, cutting the outside of the bowl with a straight bit was fine.
I take your point about the sandpaper. I was using quite a coarse grit to try to remove the burn marks.