Replies

1. 
   lat_axe | Jun 27, 2020 02:58pm | #1

   With the drum spinning and the cover up to reveal the sandpaper wrap on the drum, squirt some blade cleaner on the blackened areas. Citrus-based or other non-toxic stuff only, as this procedure wafts the liquid into the air of the shed (shop).

   Switch the machine off and drop the cover, leaving it to soak for a little while.

   When its softened to your fingernail test (machine off!) repeat the procedure except for applying one of those large rubberised sticks that are used to clean belt sanders rather than the blade cleaner squirt. This will get a good proportion of the black stuff but probably not all.

   Repeat a time of three and it will eventually come off (mostly).

   You can also try applying a rough sanding sponge rather than the rubber stick to the last remnants. You really do have to be very careful, though, applying things to that big spinning drum. Apply the rubbers to the top of the drum where it's moving away from you. Let go if there's any sign of snatch - although in practice the drum flings the end of the rubber up and away, rather than sucking your hand in.

   Do I recommend this procedure? No. But it is possible; and I did use it many a time to clean burnt stuff off my own drum sander when I had one. But I am ever so careful with these things as I hate pain. :-)

   If you think about it, though, it's not really any different to applying a piece of wood to a stationary belt sander or a plane blade to a grinder.

   Lataxe

2. 
   ral3wood | Jun 27, 2020 03:45pm | #2

   I have a Performax 22-44 sander* and you named the two woods I use most often - also the two woods that most often have issues with that "burning" especially with wider boards. The only answer I am aware of is slower speeds (no higher than 30) or, better yet, take thinner passes - I have one of those digital imperial calipers that I find invaluable. Typically a quarter of a turn on the Performax adjuster is equivalent to 1/64" and I try not to take deeper "cuts" than that with those woods - especially as I approach the final thickness.

   With that in mind, I now typically run boards through the planer to get them within 1/16" of final dimension and finish each with side with two passes of the sander.

   * - I actually have the oscillating drum sander one and that does help reduce that burning problem, but also can leave some odd nonlinear scratch patterns...

3. 
   mikeinohio | Jun 27, 2020 04:00pm | #3

   Hi Dave,

   Is the burning only happening at the outer edges of the drum?

   I have a little Performax 10-20 and the outer inch or so on both the left and the right side of the drum will leave burn marks on sensitive woods like cherry and maple.

   I've always attributed this to the fold the sandpaper makes as it enters the clamp mechanism. It seems the fold and 1/2 inch of paper close to the fold stick out a few thousandths more than the paper at the center of the drum. I try to avoid the edges if the workpiece allows.

   On the other hand, if the burning is always on just one side, your parallelism adjustment may be a little off.

   Finally, if you are getting burning at various places along the drum, Lataxe's suggestion that the paper is loaded and/or in need of replacement is the likely answer.

4. 
   john_c2 | Jun 27, 2020 05:59pm | #4

   Its a fault common to every drum sander I've ever used. The only cure is to avoid being too aggressive. Slow speed and light passes are the best way to avoid it.

   I've spent a bunch of time getting the black rings off the paper, but the problem pops back up in the same spot. Its wasted time. Use the rest of the drum if you can, and get as much use of the paper before chucking it.

   The problem is more frequent on the finer grits. It's just a pain.

5. 
   _mj_ | Jun 27, 2020 06:48pm | #5

   Synthetic wine corks work as well as the rubber sticks for cleaning sanding belts. For some reason I never run out of them.

6. 
   10_finger_dave | Jun 27, 2020 11:52pm | #6

   Thanks everyone for your thoughts and comments. When this first started, it was probably caused by a tight knot. I have experienced this burning over the entire width of the drum (I have the 16/32). Replacing the sandpaper is somewhat tedious due to the fact that the final tightening clamp is not on the outside end of the drum, but next to the sliding gate, so I am reluctant to change and use small pieces of painters tape to mark the bad spots on the drum. I believe the drum and bed are pretty parallel, I caliper the wood when it comes out and although not exact, the thickness is close on both edges. I usually sand with 120 or 150, saving the final sanding to an orbital. Does anyone use 80 grit?

7. 
   lat_axe | Jun 28, 2020 04:20am | #7

   Although they advertise the machine as able to sand 32" wide boards or doors, in practice such an attempt never ended well. Hardly started, in fact.

   At one time I used the drum sander to smooth machine-planed pieces and to get them to an exact thickness. Mine was capable of doing that, once the bed had been shimmed correctly and a rubberised feed belt used rather than the original sandpaper feed belt, which was rather bumpy, especially around the joint.

   It's no substitute for a thickness planer of decent quality though. And it never really leaves a smooth surface either: the fine parallel scratches are still just visible even with 240 grit paper.

   As others have said, very light passes and slow speeds became the order of the day for everything really .... but especially any timber with a lot of sugars or gums in them (that maple and cherry, for example). It's the sugars and gums that burn easily from the friction inherent in sanding.

   Bigger grit paper such as 80 grit were least prone to burning - but using them undermines the use of the machine to smooth. I was soon smoothing with planes and scrapers anyway, which is a lot faster and more satisfying. No burning from them!

   The thickness sander ended up making stringing and banding of an exact thickness, which it does very well once the drum and bed are parallel. But you don't need 16 inches for that. And I eventually began to use a specialist plane and scraper for doing the thicknessing of stringing & banding too.

   I sold the machine two years ago for twice what I paid for it albeit significantly less than what a new one costs now. Twenty years ago they were inexpensive (mine was £299). I notice the exact same thing is generally for sale these days at £800-£1300, depending on the badge stuck on it.

   There are better machines for a hobbyist to use for thicknessing or smoothing. Machines that work well cost a lot, lot more. £2500 for a Powermatic, for example. And I bet it still burns stuff if used too vigorously.

   Lataxe

8. 
   john_c2 | Jun 28, 2020 06:21am | #8

   I tried 80 grit once. It was just way too course. I don't know who would ever use 36 grit. I don't think you could ever get those scratches out.

   Just about the only grit I've used is 120. And I don't use mine on furniture parts, at all. But I make a lot of Shaker boxes, and those parts have to be very accurately thicknessed from between .050 to .100 inches. Far too thin for a thickness planer. The only tool that will do the job is the drum sander, and it's pretty tedious work. I can do a ton of parts with one wrap, and another time I'll get a burn mark 5 minutes in.

   I also mark the burned spot with a piece of tape and work around it, trying to salvage some use from the paper. Its a pain, but I've come to believe it's just inherent to that type of machine.