What Brush Sanders Can and Cannot Do

Brush sanders are useful, but like any tool they have certain limitations. March 9, 2008

Question
In our door shop we manufacture roughly 150 doors per day. We use an edge sander and widebelt, then putty the joints and sand with 5" orbitals. We have not found a machine that can profile sand and remove putty for a nice finish. Any process/equipment advice is welcome!

Forum Responses
(Cabinetmaking Forum)
From contributor J:
You probably don't won't to hear this, but skip the brush sanders. They don't work as advertised and will give you a lot of grief. We make a little over 400 doors a day and after the doors leave the widebelt, they get an edge profiled on them. Then it's off to the sanding tables where several people putty, hand sand (some with orbitals and some with blocks) and check for defects. By far this is the biggest bottleneck. After they are hand sanded, then it's off to the wide orbital, then they are drilled and bound for shipment.

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From contributor C:
Just to set the record straight, I do not hope that there are any of my competitors that are out there saying that brush sanding machines can remove putty, because they will not. When you think of a brush sanding machine, think of only the top surface of your part. It will remove loose fibers and break sharp edges. It will clean up the profile and the stiles and rails and make the finish sanding even all over the door. This will then make your stain color come out even. When it's time to sealer sand or sand between coats, the machine is used again for smoothing out the sealer coat and for making a scratch pattern the topcoat can stick to. Now the edge breaking in the wood before stain and sealer makes the brush sanders not break through the edges in the sealer coat. (Big note here.) Please test this before buying a machine, as sealer and stain coats do change from customer to customer. Most companies offer you testing before buying a machine like this.

This is what the brush sander will not do.
1) It will not remove cross grain scratches. Only one machine will do that and it's an automatic orbital sander.
2) It will not remove putty from your door. It might smooth it a little, but not calibrate it off like you want.
3) It will not remove scratches or other imperfections in your door.

4) It will not sand the outside vertical edge of your door, as the brush will move over the edge and not down the edge.
5) In general, your product has to be ready to finish before it comes to the brush sander before you are going to get the benefits of the brush sander.

It is estimated that in the United States there are about 2000 brush sanders sanding kitchen cabinet doors in production lines before sealer and after sealer. I represent the QuickWood brand of finishing sanders.