Sanding Question...

[BILL DONAHUE]

Tonight, I sanded a Norfolk Island pine vase on the lathe with an angle drill as I've always done. Got some pretty deep lines in the direction of the lathe movement so I attemped to hand sand them out in the direction of the grain. It took a long time and progress was slow and then I had an idea. For the first time I used a random orbital sander as the lathe turned and it did the job. So that raised the question - why do all turners (at least the ones I know) use an angle drill for their sanding? Am I missing something?

[Vince Welch]

Hi Bill,

While ROS work well with the higher grits such as 220 and higher... angle drill provide the torque to allow you to sand out deep scratches and or tool marks with the lower grits.

I use one process... I start at a low grit and progress though all my grits lowering my lathe speed as I progress through the grits. I also use a firm innerface pad for the lower grits, medium pad for 150-220 grits and a soft pad for the higher grits because it only take a light touch with little pressure when I get out scratches at the higher grits. I have a sanding suggestion sheet that out lines this process I can email you or anyone who might find it helpful. Woodnwonders@excite.com.
Vince

[John Keeton]

Bill, you should take Vince up on the offer - he knows more about sanding than most!!

[Doug Herzberg]

Bill, I've used a ROS on a platter with some success. It hadn't occurred to me to try it on a curved surface.

[Bernie Weishapl]

Bill I haven't used a ROS but was having a similar problem to what you describe. I called and talked with Vince. I started using his method and it does make a difference especially concerning the pads and the speed of the lathe. At 280 grit I am sanding at 300 rpm and around 150 to 200 rpm from 360 to 600 grit with little pressure and a soft pad.

[Prashun Patel]

Bill, you've heard from experts already, but I'll throw out my reason: my ROS is too big to fit into vessels. The angle drill gets into most situations for me. There exist small ROS's, but they're expensive. The angle drill is cheap and effective.

For me, ALL the work is at the lower grits. Once you get those tool marks out, I find I only need a minute or less at each higher grit. And, as long as I use light touch and don't skip grits, it hasn't much mattered whether I use a drill or even held the paper by hand.

[Dan Forman]

I've used a variety of things for sanding, but my favorite so far is the high speed technique using an angle grinder.


Here is a link to the article that turned me on to this technique. It runs contrary to what most will recommend here, but I suggest you give it a try. I have been thrilled with the results, it takes much less time than using a drill, and I seldom have to go back to remove deeper scratches that were missed on the first go round. As Bill explains in the article, you can use either the hard sanding discs or a Skilton sanding pad (the one made in Australia), I have had better luck on the inside of bowls with the latter, used with Norton Blue Ice ceramic discs from The Sanding Glove, especially for smaller bowls, where the hard discs don't fit as well. For this I use the yellow interface pad from Vince, shown in the photo. The Blue Ice ceramic discs discs are more expensive than the blue traditional discs, but they last much longer at high speeds. http://www.billneddow.com/f/High_Speed_Sanding_Article.pdf

With this outfit I sand at about 6,000 to 8,000 RPM. If requires a light touch, but works great. There are a few others on the Creek that use this method too, and they are likewise happy with it.

I have also used a 5" dual action ROS for the outside of bowls, and it works pretty well, but it's limited to the outside. Metabo makes a small, 3 1/8" random orbit sander that also works pretty well, especially for trouble spots such as from tear out. With some care, it can be used inside of smaller bowls by sticking smaller sanding pads on the main pad.

Dan

[Reed Gray]

When I compared the Blue Ice discs to Vince's blue discs, I got the same amount of wear out of them. I do sand at slow drill and lathe speeds because all my bowls are warped. Others recommend the high speeds, and I found they work better for me if the form is more open and has very little change in the transition area. For removing rough spots, the slow speeds just seem to work better for me.

robo hippy

[Bill Neddow]

I like the random orbit sander on the outside of bowls. It works great and certainly gives a good variety to the scratch pattern (making them invisible). However, on the inside of a bowl, the walls interfere with the orbit action of the sander and I feel it does not work very efficiently.

[David DeCristoforo]

Good question. I use one myself. I try to position it so that the spin of the pad is in the opposite direction of the lathe rotation and I slow the lathe way down. I also do a lot of sanding with the lathe stopped. There are a lot of times when the larger pad on the ROS works better than the smaller ones typically used in a right angle drill. Obviously, the larger pad will not work well in many situations so I use it primarily on the outside surfaces.

Btw, I always give the piece a "once over" by hand with each grit after sanding with the RO. I always did this when I did "flat work" and it really helped to eliminate any of those little spirals that RO can leave behind. So my "final" sanding is always "by hand".

[Dan Forman]

Reed --- The Blue Ice really shine at high speed. The blue discs from Vince are about shot after one bowl on high speed, not so the Blue Ice. The ceramics are designed to fracture at high speed, constantly exposing new edges, similar to a friable grinding wheel. Bill says they don't do that at drill speeds, so they tend to dull and clog. I have found that small bowls with steep sides can still be done at high speeds, but only with the Skilton pad and extra radiused pad as pictured.

Dan

[Thomas Canfield]

I use a ROS for the outside of larger diameter work. The relative stiff sanding pad, larger diameter (5 or 6"), and handle makes it hard to use on the inside of anything except a shallow flat bottom platter or very large shallow bowl. The ROS also is more prone to sand a flat area on a curve than the more flexible smaller discs. The angle grinder with either 2" or 3" pads and can be used inside easier. Another tool to consider is an angle grinder when you really need to start with 40grit which I have had to do on the inside of some void surface pieces that would not allow for sanding on the lathe and had to be all hand sanded.

[robert baccus]

I have a ROS but seldom use it. on the outside i use a 5 or 6" sears flex-shaft pad with the blue stuff. on the inside i use 2" air sanders--they hardly scratch at the high rpm even with 80 grit. use a softer pad and 150-220 behind the 80 grit. the air grinders(right angle) are aslo good for contours and touchups such as glue-epoxy removal. also handy is a long(6"+12") shart on the drill and 2"pads for deep sanding on bowls.------old forester

[Vince Welch]

Reed --- The Blue Ice really shine at high speed. The blue discs from Vince are about shot after one bowl on high speed, not so the Blue Ice. The ceramics are designed to fracture at high speed, constantly exposing new edges, similar to a friable grinding wheel. Bill says they don't do that at drill speeds, so they tend to dull and clog. I have found that small bowls with steep sides can still be done at high speeds, but only with the Skilton pad and extra radiused pad as pictured.

Dan
Hi Dan,
Any disc used at a high rate of speed will make a piece shine because the disc is burnish the material and not "sanding"! There is two things that can happen when using a sanding disc and sometimes a little of both happens at the same time. One... the disc is cutting into the piece "sanding" or second it is skidding or skating over the surface and not cutting the material "burnishing"! I do agree with you Ceramic fractures differently than Alunimuim Oxide(AO)... but why??? The reason is Ceramic is a softer material. The top edge tends to round over rather then fracture to a sharp point like AO. So as ceramic wears towards the base where the grainial is the widest the scratchs tend to be wider on ones work peice than using AO. Also because Ceramic is softer as it will not fracture the same as AO. Lastly, Ceramic is used in the metal market and as many of you know Ceramic is now used for brake pads on our cars. Why... it does not heat up and fracture like Semi Metallic did that we use to use on our brakes. What I teach to folks is to learn to feel the resistance of your disc to your work piece. Many folks talk about learning to "feel the cut" when using your lathe tools gouges and such right....well... I talk about feeling the resistance when sanding your work. The only way to be able to do that is by sanding with controlled speed. When one is sanding at 6,000 or 8,000 rpm I beleive it is very very difficult if not completely impossible to sense any resistance from the abrasive but rather just hang on and go go go!!! For as many people out there turning there are probobly as many different ways to sand and finish a peice. It is always interesting to see different ways to do things.
Vince

[Reed Gray]

Dan,
When I test compared the Blue Ice and Vince's blue discs, I used an identical set of 4 cored myrtle bowls from the same tree. Both sanded out the 3 bigger bowls about the same. I did have to use an extra 80 grit disc from Vince's stuff because it tends to fracture off the plastic backing. When I got to the 4th bowl, it was time for new discs, but I sanded them out any way because they were small, maybe 7 inches. I think here Vince's discs had a slight edge. Slow drill speeds, 600 and less, and slow lathe speeds, 20 rpm or so. Also, the bowls were LDD soaked, which does make the sanding a lot easier, and the discs don't clog up as much. Myrtle, if you have never sanded it before is pretty hard.

I did notice that the fiber paper on the Norton discs tended to bend or wrinkle more than the plastic backing of Vince's discs. The plastic, when it does wrinkle does seem to lay back down, but the paper didn't. Unique short fiber, kind of like particle board. Much more tear resistant than standard paper backed discs.

robo hippy

[Dan Forman]

Vince --- When I said "shine", I was speaking metaphorically, as in set themselves apart. I'm relying on Bill's expertise, as he spent a long time researching his article, and he says that the ceramics fracture better at high speed, but only round over on wood at drill speeds.

In my experience though, the bowls I have used high speed sanding on have come out looking much better than the ones I used the drill on, which almost always still showed left over scratches, much to my chagrin. I tried hard to follow the accepted procedures, but seldom got good results. Now that may well be my own fault, and I'll concede that, as it seems to work fine for others. Could be that my tool technique (or lack thereof) :) leaves a lot more inconsistencies and tool marks to sand out too. However, I've been able to do a much better job in half the time or less with the high speed technique, so I will stick with it and encourage others to try it for themselves. For me, it has turned sanding from a drudgery into something that borders on fun.

One does have to maintain a light touch, and watch to keep edges from digging in with the hard discs, and it can't be done with the lathe off, or flat spots would be pretty much unavoidable. One advantage to the one piece hard discs (Roloc), is that they are always concentric to the tool, whereas when using interface pads and discs, it's nearly impossible to get them on dead center, so the whole works frequently feels like it's bouncing around on the workpiece. One can also sand right up tight to a bead or other embellishment without obliterating it.

Dan

[Dan Forman]

Dan,
When I test compared the Blue Ice and Vince's blue discs, I used an identical set of 4 cored myrtle bowls from the same tree. Both sanded out the 3 bigger bowls about the same. I did have to use an extra 80 grit disc from Vince's stuff because it tends to fracture off the plastic backing. When I got to the 4th bowl, it was time for new discs, but I sanded them out any way because they were small, maybe 7 inches. I think here Vince's discs had a slight edge. Slow drill speeds, 600 and less, and slow lathe speeds, 20 rpm or so. Also, the bowls were LDD soaked, which does make the sanding a lot easier, and the discs don't clog up as much. Myrtle, if you have never sanded it before is pretty hard.

robo hippy

Reed --- When I was comparing Vinces blue disc to Dry Ice discs, it was using both at high speed, 6 -8000 rpm, and the lathe turning about 800 RPM. I don't know if Vince's discs were designed to be used at that speed, probably not. Vinces get a lot better milage at lower speeds than they do at high speed. They still did a good job, just wore out faster. Per Bill's article, the Dry Ice discs, due to the way they fracture, should have done better for you if used at high speed, which I know is not practical for your warped bowls.

Dan

[Rick Markham]

I'm still just using the sanders God stuck at the end of my arms. Call me crazy but I actually enjoy hand sanding on the lathe.

[Prashun Patel]

Rick, I'm going to send you a bunch of completed projects that you can sand for me. I'll pay the shipping, you can keep the dust for free. Whatsay?

[Reed Gray]

Okay Rick, you ARE crazy.

robo hippy