Troubleshooting Belt Loading when Sanding White Pine

What makes sander belts gum up, and how can you get them clean? Shop operators share experiences and ideas. June 28, 2005

I'm sanding pine panels with a 37 x 75 wide belt sander. I am wondering, what is the best belt/abrasive material to use for pine?

Forum Responses
(Cabinetmaking Forum)
From contributor D:
In my experience, it’s best to use the same type of belts you would use for any kind of wood. I can’t remember the coating specifications - but your biggest problem will be loading. Pine is the worst, so cleaning your belts will become the issue.

From contributor J:
We sand thousands of square feet in white pine panels per day. We have learned that the belts load up so fast that there really isn't anything you can do about it. As soon as you try to clean it, it will only be gummed up in about 10 minutes.

I've never noticed rub marks. However, all our end product is so unfinished and the end user usually does a little hand sanding before finishing. We use a regular 3M sanding belt. One thing that I think will definitely help is a longer belt length. Ours is only 60" now. Our new sander will have 103" belt lengths.

From Gene Wengert, forum technical advisor:
You need to specify that the belts are "open coat", and you need to make sure that the pine has had the “pitch set” during drying.

From contributor L:
For cleaning the belts, we had a special block of the belt cleaning rubber made up. It was 13" x 13" x 2" thick. We made a small plywood platform with a stop to hold the rubber in place, and we would send it through just like a piece of stock, and 3 passes covered the 37" width of the belt. We would write on the platform what thickness it was at, and rewrite it as it wore down as to not stall the machine. It worked great and was very safe.

From contributor D:
To contributor L: We tried the same thing. We glued the large cleaner pad to a panel and hoped to send it through the machine to clean, but it didn’t work. We didn’t design anything to hold it in place, we simply put it on a conveyor and sent it through. It grabbed on too much, tearing chunks out of the rubber pad and made quite a vibration and noise, and then it broke both belts.

From contributor L:
To contributor D: We never had a problem with sending the large piece through. The trick was to just barley touch the rubber and to send it through at almost dead slow. Maybe the back side support/stop was what did it for us. We never had to glue the rubber down. I figured as it got thinner, we would eventually have to glue it down.

From contributor J:
I use a product called reuzit. It comes in a five gallon can, and I immerse the belt in it and wait about twenty seconds, and then hose it off. They come out completely clean. I can clean a dozen belts in about fifteen minutes.

From contributor D:
To contributor D: I’ve tried reuzit, and it works well. We mixed up a 55 gal drum of it, and would soak it, and then spray rinse with a little water pressure. Even though we used the 3m film belts with the miter t splice (splice is actually thinner than the belt by 2-3 thousands), eventually the splices would swell and give us chatter marks. When we switched to cleaning with the service company stick, we cleaned with the belt on the machine, closed the door, and went right back to sanding.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor R:
When sanding white pine I try to run red oak alternating with the pine. I find that my belts stay very clean when I do this.