January 9, 2011

I posted the following question on a Luthier Community Forum.

I use an 18″ Grizzly Drum Sander to thickness backs and sides.  I use 100 grit paper, keep it clean, advance mere micro millimeters for each pass yet still can’t avoid burning.  Any suggestions?  The feed rate has been tested from slowest to fastest, yet it doesn’t seem to make a difference.  The harder the wood, the more prone it is to burning.  Must
I accept burning as part of the process (I can scrape it off in the end)?

  • My first thought is that the belts are moving too fast.  Can you adjust the speed of the belts??  I assume that the feed pressure is appropriate given that  you are able to adjust the thickness w/o difficulty.  100 grit is fairly common in this application.
  • Are you sanding with the grain? Sanding with the grain on high resin woods can cause burning. Try sanding at an angle against the grain. The greater the angle the better.
  • I have a Performax 16-32 and found out early on that you need to use a heavy grit (80 or lower) to take the initial pass.  After you have removed a bit, go to 100 or higher.  This works very well for me. Also, with high resin woods, the paper will not gum up as quickly.  If you try to remove the wood with a higher grit, it will  burn and gum up.  Use a heavy grit to remove the bulk of it, and go to a higher grit to smooth it out.
  • A dust collector of adequate CFMs is a must.  That would be the first thing I’d look at.  You have to get the dust out of there efficiently as the sanding is happening in order to prevent clogging of the abrasive.  If you have a good dust collector on there, then the problem could be the design of the sander – how well it’s designed to maximize dust removal.  I have a Woodmaster, which excels in this regard.
  • I use the little Performax (10-20) so I have to pass on each side to thickness a plate.  I have never had a problem with burning, but I keep my sanding belt really clean (I have a sanding “eraser” next to it and use it about every 4th pass) and use a Grizzly product that comes in 10′ or 30′ rolls for about 4 bucks.  It fabric backed and doesn’t loat much anyways.  I get 3 out of the small one, if I’m really careful cutting.  Also, when wrapping the drum I don’t go right up tight to eachother, but leave a little gap of about 3mm.  I find that any dust not pulled into the hose lodges in there rather than the grit.  I’ve done Sitka and Englemann spruce, and the hardwoods from mahogany to ebony, no issues.  Hope this helps.