Yesterday I finished four pen kits with wood blanks. When I finished the last one, I looked at it under the light over my lathe. It had what looked like scratches but were around the blank and were equally spaced. Scratches would be random, I would think. Checked all the blanks and they show the same thing. OK when viewed but the "marks" show up when the blank is seen at an angle.
Sequence: turn to size; sand with the grain 150-240-320-400-600; apply 4-6 coats of thin CA with a paper towel and quick shot of accelerator; polished with Hutt polish. Not sure if I can get a good photo to show the blank.
Adding to the sequence- Arrrggghhh!
I have looked at a couple of YT videos but each one has a slightly different approach. Your suggestions are most welcome.
Just want to check here...are you SURE they are scratches? I've sometimes thought I had left scratches behind, but after real close inspection (which usually requires me to use my close up glasses), sometimes this is a characteristic of the wood grain. The evenness of the marks, is why I ask... Can you get a much closer look, to see if its actually scratches, vs. a natural grain characteristic? Sometimes a characteristic like this, might only occur in certain spots along the length of the blank, and radially may only occur at certain points around, or may extend all the way around.
In any case...just a thought on grit. I think 150 is a rather coarse and harsh grit to start with for a turned pen blank. I myself will rarely start lower than 400, and then 320 only if I simply cannot correct something with 400. Even then, I'll often try to correct any such defect with a tool, and keep using 400 as the starting grit. I think 150 and 240, relative to a turned pen blank, are rather coarse. Its a scale thing, and you would have to have had pretty rough tooling, to need to sand at those grits, right? In the past, when I started pens, I would sand with 120, 180, 240, etc. I always had problems with scratches. Those lower grits DIG, even when you aren't really applying pressure, shred the fine grain, and otherwise, leave things a mess. Once I learned that there is a scale factor...and that turning a pen, a simple spindle, is not the same as turning a bowl or platter, and I started at higher and higher grits until settling on 400, sanding became a lot easier for pens. Sanding out 400 grit scratches is a HECK of a lot easier than 120, 180 or 240 grit scratches...and, it is far, far less damaging to the grain fibers. IMO even 320 can sometimes shred fibers, and for such a finely turned thing (blanks often end up only a few hundredths thick or so), coarse grits shouldn't be necessary.
This is often quite in contrast to bowls in my experience. I try my best to avoid tearout, and if I get any with a bowl or platter, I try to use scrapers, sheer scraping, etc. with sharp tools to clean it up. Still, if there are any remnants, 180 grit will usually take care of the issue a lot faster, and I will start at 180 or 220 grit with bowls and platters most of the time. The scale of these items, though, is SO MUCH LARGER than the scale of a pen, the scratch factor is quite different. Not to mention the difference in grain orientation, and the nature of engrain vs. long grain sanding and all that.
If you could get a close up picture of your pens, so we could see the marks you are referring to...it might help identify if they are indeed scratches, or maybe just a grain characteristic.
