Good afternoon! I have just discovered this thread, and am very excited to fine tune my sanding skills. I have generally been following your techniques, but have found that I tend to get an uneven or burnished finish. When I turn the pen, there are dark and bright "sides" to the finish. Very inconsistent across the sanded blank. I usually use CA finish, so I am unsure if I am sanding the wood too fast but don't see the "burned" side until the CA is polished. Any thoughts?
Sanding & Polishing Basics
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leehljp
Member Liaison
Two thoughts from me:
1. Too much pressure with real fine sandpaper/micromesh and too high speed causes burnishing.
2. one side versus another can be caused by:
A. soft wood in the grain versus hard grain and this happens on occasion as Sanding takes off more of the softer parts on one side;
B. bent mandrel or burr in the end point going into the small mandrel cup on the end. These cause a wobble and makes one side receive more sanding pressure or rubbing than with a perfect mandrel or TBC.
Some other guys may have different ideas. Listen to all of them.
1. Too much pressure with real fine sandpaper/micromesh and too high speed causes burnishing.
2. one side versus another can be caused by:
A. soft wood in the grain versus hard grain and this happens on occasion as Sanding takes off more of the softer parts on one side;
B. bent mandrel or burr in the end point going into the small mandrel cup on the end. These cause a wobble and makes one side receive more sanding pressure or rubbing than with a perfect mandrel or TBC.
Some other guys may have different ideas. Listen to all of them.
Hank is right. You are probably using too much pressure for those finer grits. I would also recommend with the final couple of grits, it helps to sand with the grain, after sanding with the lathe on. Just some manual sanding with the grain, light to moderate pressure (enough to do the job, but not so much as to burnish or anything like that.) Look for spots where the grain may have been torn by lower grits, try to clean those areas up, get the blank as consistent as possible all the way around.
I have sanded at a wide range of RPMs...from 1000 up to nearly 4000. With the right pressure (not too much), you shouldn't have problems with the wood burning or burnishing. I usually try to sand at around 2000-2500 rpm these days, though, maybe even lower with larger pens (larger diameter, especially caps...maybe 1800).
Approach sanding as a delicate process...not a rough or heavy handed process. This is your finish...the final process. Approach it with care, and a measured hand. Attend to the wood, or the acrylic, and work out the rough spots carefully, meticulously.
Good points sir, I would agree I need to slow my sanding speed down. There seems to be no real advantage to sand the wood at a higher speed. I do speed it up when I am sanding and polishing the CA though. Thanks!
Great points Jon! I think just need to slow down and as you say, take my time. The manual sanding method you mentioned in the original article is new to me, so I will definitely utilize it. As someone who is newer to turning, I was utilizing the lathe too much to sand and not do much by hand. Thanks for the great response!