Tools and Tool Buying

[nosoup4u]

I have two sanders, an older B&D oribital, and a year old PC ROS. The finishing department (my wife) complains that using either results in small "curly q's" in the finish. Sometimes I read about "finish sanders" is this just another name for one of the two aforementioned sanders, or is it something special designed to be used just before, during or after applying finishes?

[jandsjacobson99]

Yeah, finish sanders, palm sanders, orbital sanders, basically the same thing.  Usually seen in a 1/4 or 1/3 sheet configuration.  I don't like them much; my ROS moves much quicker and leaves a better finish in less time.  If the ROS isn't quite working, you might check technique.  Are you moving through the grits appropriately?  Are you going to a high enough grit (some say 180, other's say 220)?  Last, make sure the tool is being used properly: don't press down too much, move the tool slowly over the surface, keep the tool flat, etc. 

[mathisonr1]

Types of sanders are almost endless. As far as the curly ques, work through your grits and sand slower (don't move sander from side to side so fast) and let the 'radom orbit' part of your sander do it's job.

Rick

[amateur60]

The final sanding must be done in a straight line, with the grain. NO ROS, no orbital sanders, and unless you have a golden touch no best anding either, I think there are still some straight line finishing sanders that are air powered, if you have a large enough compressor, and possibly some 1/2 sheet finishing sanders may have a straight-line mode. But the straight line powered sanders aren't much if any faster than sanding by hand anyway, and between coats of finish you really don't want to sand very quickly, you want it to go slow so you have control. All this makes hand sanding the ONLY practical method outside of an industrial setting . Use a padded sanding block, and sand with the grain using the same grit as the final grit you used an ROS on. Again. HAND SANDING is ALWAYS the most appropriate final sanding step before finishing. It's also the only method to use sanding between coats of finish. Most woods only need to be sanded to about 180 grit, perhaps a little finer for hardwoods to be finished with an oil finish. Between coats of finish 315 grit works well.

[Beaver Creek Woodworks]

One other tip I would offer is to clean the piece before proceeding to the next grit.  If left on the piece, the previous grit can leave scratches like you describe.

[123098]

I do not know about the electric Random Orbit Sanders as I use pneumatic types.  But the ROS come in a 3/16" and 3/32" orbit, then straight line models.  There are 5" or 6" round disks that are hook and loop or glue on (PSA), with holes for vac. and without, then there are square, oblong and triangular shapes as well. We will not get into the smaller specialty sanders for use primarily in turning or get into the "profile" sander world, the list goes on and on... 

Any sander for any purpose (or by hand for that matter) will leave sanding marks if not sanded with a fine enough grit or the final sanding.

[amateur60]

The only effective way to avoid visible sanding marks it to avoid cross grain sanding.  That means either straight line sanders, or hand sanding.  ROS isn't sufficient for the final finishing and means shoddy work. 

Trying to just eliminate visible marks by sanding finer can generate other problems,  making staining more complicated, and potentially creating adhesion problems with finishes.  For furniture that will receive a film finish you seldom need to sand finer than 180 grit, and 220 grit should be about the finest level used on bare wood.  If an oil finish is to be used, you can go a notch finer to 315 grit, though there will be very little visible benefit.