Sanding bowls

[Charles Castle]

I have recently had to sand two bowls, prior to putting a final wax coat on. The problem I have is that If I sand around the junction between the edge and the base on the inside, I get circular marks. These cannot be removed. If I try and sand with the grain, there are two areas at each end where I can't get a smooth surface. Does anyone have any suggestions?

[ubeaut]

G'day Charles - Rotary Sander http://www.ubeaut.com.au/rotary1.htm

[ubeaut]

G'day Charles - Sorry forgot that not every bowl comes off a lathe. All I can suggest is a random orbital sander or lots of patience. Use less of the courser grits if possible and eradicate the previous grit marks before going on to the next finest grit.

Cheers - Neil

[MathewA]

This is the most important part of turning and the least liked and understood. Use progressively finer sand paper - don't cheap out and skip a grit. 80 grit, 120, 150, 180, 220, 240, 320... If you skip a grit size you run the risk of leaving circular scratches. I tend to sand up to 150 with dry paper then switch to wet dry paper all the way up to 600 and then buff to a polished finish with a cloth buffing wheel on a drill press or grinder. Be patient with sanding, If you try to rush or push it you end up with a very poor finish and feel. When I get to the higher grits and think I've sanded enough I sand somemore, I always find small scratches later that I need to sand out by going back to a lower grit. Sand at a slow speed. For some reason most people think to crank the lathe up and sand at a high rpm. Problem is the sand paper can't "unload" and it starts to burnish (compress the wood fibers) and possibly burn the wood. Later as the humidity falls and rises the fibers will start to un-compress and stand up making for a very poor finish. At 500rpm or less the sand paper has lots of time to unload the dust and work the way it was intended - to cut the fibers off flush in stread of flattening them over. Another thing that is important, if your lathe is capable, is to reverse the direction when sanding. I like to sand in forwards and reverse with each grit size before moving up to the next grit. And finally I like to buff to a nice finish. If the wood is purous like oak I use a clean buffing wheel with nothing on it. If it's a hardwood with little or no pours like a rosewood I use a white buffing compound.

[Charles Castle]

Thank you for your suggestions MathewA. I am not turning the bowls, someone else did that. One I chip carved a pattern in the centre, the other was given to us and got terribly badly stained when some fruit went bad in it. The latter one is Huon pine. I don't have a lathe.
Your suggestions about not skipping a grade of grit are very helpful. Neils idea of not doing too much with coarser grits will also be helpful. Since I sent my first message I've found another trick - I use a cork sanding block with the abrasvie paper bent over the short end, and psuh that up against the junction of the wall and the base. That seems to work a bit better.