Sanding speed questions

[zukinut]

This may very well be the dumbest question ever.  But I'm gonna ask it anyway. 

When it comes to sander speeds I've always just educated guessed it and had good luck and excellent results. However, what is the rhyme/reason behind it.  Should you use lower speeds with lower grit and higher speed with higher grit? Or does speed only matter with particular woods, or?

Any tips, advice or help is greatly appreciated 

Will

 

[grbmds]

Doesn't seem like a dumb question since most sanders are variable speed. I almost never use anything but the max speed no matter what the grit. Doesn't seem to make any difference in the finish as far as I can tell. Sometimes, if there is more vibration on the sanding surface than usual, I may turn the speed down a little which might help reduce the vibration. Otherwise, I just want to get done with the sanding as quickly as possible. The faster the speed the more material removed? Of course, I'm only basing this on my experience and don't really know if there is any good reason to turn the speed down. Maybe lower speeds are meant for materials other than wood?

 

[Cheese]

There’s no rhyme or reason to the answer. Like grbmds, I try to sand at max speed. I’d just as soon complete this task sooner rather than later.

It all depends upon what wood you’re sanding, the direction of the grain, the grit of paper you’re using and what direction you're moving with the sander.

I always start out at max speed and if the sander starts to jump around, then I’ll start to dial it down a bit. No need to over think this issue as it will never be completely understood. Festool sanders seem to be a little more susceptible to grain patterns and grain directions than the competing brands. Maybe the new Festool net sandpaper will alleviate this situation.

 

[grobkuschelig]

I think the reaction of the finish can give you some clues. If you see baking of the finish on the paper, it runs too hot, so turning down the speed might help.
If you want to polish in some oil or wax finish, it is only recommended at lower speeds.

If I have a delicate surface (thin veneer, delicate finish) I will always start on speed 1. this gives you a chance to start sanding gently and experience the effect your paper and grain choice has on the work. You can also see „how long“ you might be able to leave the sander in one place.
Starting on Max will give you a binary hit/miss situation...

As always, YMMV. But especially for touch-up, corners etc. full speed seems to me to take too much material and leave me with an undesired result.

 

[Sanderxpander]

Also, when removing paint, too high speed can make the contact area too hot, clogging the paper in no time no matter how good your dust extraction is.

But you'd find that out in five minutes if you'd try it. Just do what you've been doing; if it looks good, it is good.

 

[grbmds]

Just to clarify my answer. I was talking only about sanding on bare wood in preparation for finishing. That is what I mostly do. I hand sand in between finish coats as needed. I don't use sander for much of anything other than sanding bare wood these days.