Burning stock using drum sander

[George Bokros]

I was sanding a wide (15") on my Performax 16-32 sander. Made several light passes all was well. The next pass the stock had burn marks at one end of the drum. I was running it at a slow speed to avoid kicking it out on overload ( I do not have smart sand). I checked the paper immediately and it did not appear to be loaded up but I used the cleaning stick and made another pass. No additional burning occurred but stopped at that point and finished the leveling with my ROS.

What are the causes of the burning. Was I running too slow of a feed speed? This was a glued up panel I was trying to level and using the sander because it was too wider for my planer, could the glue joint have caused this?

Thanks for your input.

[daryl moses]

When mine does that it is either because i'm trying to take too much off at one time or running it too slow. Try just taking a very small "cut" at a moderate speed on your last couple of passes.

[George Bokros]

I thought it might be because I was running too slow of a feed. I learned some time ago that too heavy of a cut will kick it out on the overload so I guess I am over compensating by taking a light cut and a slow speed.

[glenn bradley]

Did the burn line up with the glue joint? I get burning when the abrasive loads up. Just as on the tablesaw or other machine, species, grit (tooth count), and feed speed all contribute to a poor combination. You might also do a quick check on the drum being parallel to the feed belt if the burning always occurs on one side. Take a scrap of ply or MDF and draw pencil lines across the surface. Run it through with a very light contact and check the pencil lines for even stock removal.

[Lee Schierer]

Sanding heats up the wood. Pressing hard heats it up faster. Fast speed of the drum heats it faster. Woods with a high sugar content such as cherry or maple, tend to burn more easily. Let the wood and sanding drum cool between passes. Oscillating spindle sanders overcome this to some extent.

[David Helm]

I have a Grizzly drum sander. This may sound ant-intuitive, but in my experience the best way to avoid burning is very light passes at the highest feed speed. I think the reason this works is that the drum touches any given spot for a very short time.

[Larry Anderson]

I take very light passes at the highest feed rate with my Performax 16-32 smart sand and have never had a burning problem.

[George Bokros]

I take very light passes at the highest feed rate with my Performax 16-32 smart sand and have never had a burning problem.

I have been considering adding smart sand but I keep hearing that if you learn you machine smart sand is not necessary..For me smart sand is the only way to know you are using the fasted feed speed you can

Larry are you saying you turn up the speed all the way and let smart sand determine the feed rate?

[Larry Anderson]

I have been considering adding smart sand but I keep hearing that if you learn you machine smart sand is not necessary..For me smart sand is the only way to know you are using the fasted feed speed you can

Larry are you saying you turn up the speed all the way and let smart sand determine the feed rate?

Yes that's what I do. From the manual: "Try a faster feed rate or less depth of cut if the stock you are working begins to show burn marks."

[Robert Engel]

After I added hook and loop to the drum, I started getting more burning.

[David Kumm]

you also need to make sure the paper doesn't slightly overlap. I found I needed to take up slack every so often or the belt would overlap when running and cause a burn. The smart sand is not a deal breaker because you only want it to kick in sparingly. Depending on it gives you an inferior surface to staying below the amp draw that causes the feed to slow. I also used poly glue for glue ups as yellow tended to dull the grit and cause burn lines. Poly glue is much softer. I also found that grits higher than 120 ( 150 for sure ) caused a disproportionate number of burn issues. Dave

[Paul Stoops]

You don't say what grit paper you are using, but fine grit paper burns much more easily. Also, remember that the grit dulls with each pass, so maybe it is time to change out the paper.
I don't have a Smart Sand feature on my 16-32, either, so I added an ammeter to monitor motor current: http://www.sawmillcreek.org/showthread.php?213245

Paul -- Auburn, WA

[glenn bradley]

I have a Grizzly drum sander. This may sound ant-intuitive, but in my experience the best way to avoid burning is very light passes at the highest feed speed. I think the reason this works is that the drum touches any given spot for a very short time.


I take very light passes at the highest feed rate with my Performax 16-32 smart sand and have never had a burning problem.

Right. Moving the material slowly leaves the abrasive in the same place longer; ergo burning. Lighter passes will help but, as someone noted, high sugar woods like maple can even burn with light passes if the material is moving at a snail pace. Like a lot of things with machines, there is a balance; too fast and the finish is rough, too slow and there are other adverse effects. Use the Goldilocks method and you'll find a combination that's just right ;-)

[George Bokros]

You don't say what grit paper you are using, but fine grit paper burns much more easily. Also, remember that the grit dulls with each pass, so maybe it is time to change out the paper.
I don't have a Smart Sand feature on my 16-32, either, so I added an ammeter to monitor motor current: http://www.sawmillcreek.org/showthread.php?213245

Paul -- Auburn, WA

Paul I did your ammeter upgrade and it worked fine for a while but for some reason the ammeter started kicking out at 14 amp draw and shutting down the drum. I thought it was the overload on the motor but I found that the overload had not kicked out. I took the ammeter out of the loop immediately after the sander stopped and and the sander started right up without pressing the reset on the motor.

[ken masoumi]

Great thread.
I do get burn marks on my projects occasionally but I stopped trying to find out what could possibly be the cause of it , I just change the sandpaper roll and put on a new one to finish the job but keep the old roll and when I want to take a break, I bring it out ,lay it flat on a workbench and scrape off all the caked up sap or debris and make it as good as it could be,next time I need to change the roll I use that old one .
The point is, there could be a variety of reason that causes the burn marks ,if it's not the sap in the wood it could be the loosened up roll that can overlap and burn the wood, but I know for a fact a new roll of sandpaper ,properly installed will always do the trick.

[David Helm]

I also only use 100 grit. I use the sander in place of thickness planer. I generally only use highly figured woods and can't afford to buy shelix headed planer. While it is a slower process than planing, it does the job well.

[Paul Stoops]

That is very strange. As far as the control circuitry for the sander is concerned, the ammeter is a passive device. If you wired it as shown on the reference post, the box containing the meter is just an extension of the outlet on the controller and one of the motor power wires just passes through the meter current coil on its way to the outlet on the box. If you used a meter with a shunt, the results might be different.

Paul

[Ira Matheny]

My findings, using a wide-belt sander.
A. Use fastest possible speed on the feed belt
B. Never send a board thru consecutively at the same place on the belt.
C. Always send the board thru with 10 to 20% skew [alternately right, then left] until the last pass ( the belt AND the wood stays cooler!)
D. Last pass on the wood is at no change on the depth setting. Send it thru several times without adjusting.
E. Forget finer grits, as then will burn at the 'Drop-of-a-Hat'
F. Maple is the first wood to burn.
E. Flip over the board with each pass, if possible. Board stays much cooler.

[Bradley Gray]

I have occasionally had burning related to my dust collector needing to be emptied.

Dust not captured lands on the conveyor and causes burns by raising the work.

I empty the collector bags and brush off the conveyor.