Some of the sanding machines. Left to right, a random orbit with a flexible velcro pad for sanding curved objects. Another random orbit sander, with a stiff pad for flat surfaces, again velcro. Next, an oscillating multi-tool, velcro pad., as discussed here. Right, a belt sander with a sanding frame. Sanding frames let you adjust the depth of the belt, and stabilize the tool for sanding broad, flat surfaces. Mostly I use the random orbit sander with a stiff pad to clean up the backs of frames, or when they have inlet splines, to level the splines. Search "splines for several posts about the process.
The random orbit sanders and the belt sander can also be hooked up to the shop vac via an inch and a quarter hose, seen at the rear of the black sander. Another handy feature, as it really does remove the bulk of the dust. It is, however noisy, having both a sander and a shop vac running at the same time. Earplugs.
Well, I just spent some time looking for belt sanders that offer a sanding frame, and not much out there; Bosch might have one, but I couldn't track down an actual product. My sander, a Ryobi offered the frame as an optional accessory, but I can't find one now. Too bad, as it was a useful addition in terms of efficiency and preventing the belt from gouging the work surface.Belt sanders excel at rapid removal of material; the frame added control. Maybe I should save the Ryobi for resurfacing my bench tops, and get a cheap belt sander for the occasional "wood butcher" job. Using the links at right will send a few pennies my way, at no cost to you.
When using a sander with velcro attachment, especially when sanding edges, or thinner parts, it is important to keep the sander moving. If you hold it in one spot, you can melt the velcro hooks, rendering them useless. Porter-Cable does offer replacement pads, around $20.00 the last I checked.