Sanding maple difficulties

Denis, from your explanation, I think you are finding end grain areas that tend to be the bane of bowl turners. The fibers tend to want to pull out/lay over when cutting and sanding. One way to reduce the problem is to apply paste wax to the endgrain areas and run the lathe in reverse while sanding. Go back to normal direction and sand again. Work your way thru the grits while going back and forth.  You may have to do this more than once.  The areas can also be scraped or re-cut after the wax is applied but I don't pretend to be good enough to describe the process. Jim Denis Marier wrote: Lately, I have experienced difficulties when power sanding maple bowls. I do not know if it's a bad lot of wood or something else maybe white fungus? I may not have the correct word to describe the problem. After sanding from 60 to 400 grit and going back several times these white areas are still showing up. Its look like the grains of the wood are going in the opposite direction. I can also  describe it as hard white paste between rings at random location. Sometime, the white areas are found at one and two locations outside  the bowl and maybe one spot inside the bowl. The bowl could be as glassy as a mirror and when I apply tung oil the white areas turned out darker and reflect poor workmanship? Sometime I become apprehensive to sand too much.  I wonder if anyone else has  experienced the same situation.

Everyone has experienced it. It's tearout. Happens only where you are cutting uphill (rotating down into the gouge, actually) and where you're taking too broad a cut. Two places, opposite sides of the piece.

That's one of the big reasons why I like forged pattern gouges for the last few sweeps. If you rotate the gouge so that the portion engaging the wood is almost vertical, steadying with a mild rub of the lower portion of the gouge, you can sever fibers cleanly in almost any curve by using an appropriately sized gouge. This demands a close toolrest, a sharp tool, and patient cutting. When I'm finishing on hard maple the shavings are almost like threads. I put the rest just below the center, keep the handle of the gouge almost as high as the nose, and begin the cut with a slight downward motion of the nose when entering the cut.

Reason you see it so easily on hard maple is the tendency of the wood to burnish when sanded with too much heat. I like my flex shaft, steadied on the toolrest, just kissing the surface with the disc. Sands cool and quickly, though I would be real careful about grits 0f 80 or coarser, because they can grab, even in 2" diameters, hard enough to twist your wrist severely. If you see any shine on the surface prior to 400 or so, stop, raise the grain and break the hardening of the surface with a wipe of water, and resume sanding after it dries. Don't press!

I valued the information received from Jim and George. I have tried both method. I have obtained positive results from both method. Now I have learned the proper name ?tearout? to describe this situation correctly.. First I used wax sanding. The wax used for sanding was Clapham?s beeswax salad bowl finish. I used the same wax for the final finish. The second bowl was redone using a 1/4? bowl gouge producing shavings almost like threads. This being the first time using the thread savings method it faired out OK. Still, I was able to see a two ?tearouts?. I then used water to raise the grains and light sanding. In conclusion: Both method give positive results and can be used according to the situation on hand. When working with maple I will have to be more careful with the gouge and learn to detect ?tearout? and react accordingly.

In my experience, the tearout is caused by scrapers. I've quit using scrapers in bowls and am trying to hone my gouge technique. Sharpen your gouge for the final, shallow pass, and try to make a continuous cut from rim to center. Tool marks from a sharp gouge are easier to sand out than tearout from a scraper. When you go as low as 60 grit, you're creating more unnecessary work for yourself, because you have to thoroughly remove the 60 grit marks with 80 grit--and the 80 grit with 100 or 120, and on up to your highest grit. If you are going to try sanding out those dark areas, starting with 120 grit should work OK, and save time. Some turners saturate the problem area with varnish and sand it wet, or let it dry to stiffen the fibers before sanding. Since regrinding my bowl gouges to the Ellsworth grind, I've had much better success both inside and out. I use a 2" velcro sanding pad in a drill for almost everything, and can usually start with 180 grit or 220 if I'm lucky.

Ken Grunke