Power Sanding

[LANKFORD]

I jumped in to do the power bit. I have hook and loop stuff, 80 to 600 grits, and 2" diameter wheels. I also bought an angled drill with 0 to 1300rpm speed. What is the best speed for sanding? Any other tips would be appreciated.

 

[4mikee]

I like to sand about half throttle on the drill and around 500 rpm on the lathe with the drill in the 11:00 0’clock position while reversing the lathe. This seems more comfortable to me and it tends to get some of the raised grain as I am told and the dust goes away from the turner. Be careful not to put a lot of pressure on the pad and watch the angle when on the inside curve of the bowl (different approach inside) it has a tendency separate the backing from the paper and/or twist the material on the paper so it won’t hook any longer. I know this is more than you asked but what the heck. I still get a lot of pads that don’t hold up. I have four in a box now with little use that came from Klingspor’s that just didn’t hold up under normal conditions ( I’m talking a few uses). Hopefully the vendor area of the symposium will have something to contribute. Maybe someone can explain the paper problem a little better and help us both. Personally I do a lot with the Sorby type handled sanding pad, even prefer it for most sanding over a drill. Good luck.

 

[Steve Worcester]

I agree with the speeds, slow down the lathe and the drill.
Looking directly at the front of an open bowl, you would generally sand in a 9 o'clock position. The pad is canted so that only one side touches the surface, and the pad can spin clock or counterclockwise. One way will spin the pad against the direction of the bowl, which will remove more material and potentially leave more scratch marks, and the other way (with the bowls direction) will not remove as much material and leave a cleaner finish (possibly).

As far as the paper coming off the backing, that is a poor quality paper. It isn't able to take the heat you are generating. The twisting off can be a dirty backing or a Velcro that has the hooks melted down, or a bad batch of paper also.

You can see me in the vendor area and we can talk at length about it if you like.

 

[Richard Baker]

Check out Steve's products at the link below his name. They work well.

 

[CTutor]

Sand Paper

Try Industrial Abrasives their Ryno backed paper is extremely good. The paper wears out before the backing. You can get 1ydx1meter sheets of hook and loop for about $15 and make your own disks.. Works out to less than 9cents per disk

 

[Mr. Don]

sanding

Your main enemy in power sanding is HEAT....too much pressure and too high rpm. Slow down and VERY light pressure will be a big help. I learned this the hard way (a box full of pads that were nfg). Was able to refurb most with contact cement and new velcro. Still cheaper than new.....

 

[4mikee]

Steve, I'll be by to see you. Hopefully Lankford will get the same info. He's really the one asking the question. I just tagged along. Thanks.

 

[Vince Welch]

I agree with what has been said. I beleive that many people power sand with too much speed and pressure. I suggest turning the lathe down to 500 rpm or less. One might even want to remove tool marks with the lathe not running using 80 grit disc. I am able to start sanding usually with a 150-180 grit but I always start with 80 grit. For me there is success and frustation that work against each other concerning sanding. When things are going well my success level is up and my frustration level is down and vs versa. By starting with 80 grit and using an firm interface pad I work through the grits 80,120,150,180,220. These are small steps but I am not spending much time with each grit because all I am doing is cleaning up the previous grit markings. Remember I got all tool marks out with the 80 grit in the beginning. From 220 I use a soft innerface pad and progress to 280, 320,400 and sometimes 600. With the soft innerface pad I am sanding lightly. I use a micro hook system to hold my discs and it holds stronger than any hook and loop product I have tried. The discs I use will work with hook and loop just as others discs do. With heat and pressure all H&L will have failure. With micro hook backing there is ALOT more hooks at attach your discs. Also, in addition to working better (IMHO) the micro hook systems is LESS costly then what most people are selling out there. Hope this helps.

You can see me in the vendor area and we can talk more if you would like.

 

[4mikee]

If I accompish nothing else next week the foremost problem I have and perhaps Lankford is the same, is tearout. No matter what I do I have just enough of endgrain tearout to be frustrating. It may be punky spalted wood or bone dry exotic. If not for that I could start higher than 80. See you there.

 

[LANKFORD]

Thanks for the tips. As matter of possible interest I bought a Milwaukee angled drill called close-quarters drill. The angle is about 55 degrees. 3/8" chuck, it has a reversable switch. The on switch is a big squeeze type on the front and as you squeeze it, it goes from 0 to 1300 rpm. Nice feel and comfortable angle. Amazon $139.00.

 

[Marc Himes]

sanding problems

I have had a problem with sanding marks, probably from using too much pressure or stopping at 320 grit paper. My son let me borrow his random oscillating sander and many of these marks were no longer visible. I haven't seen the random oscillating sanders in less than 5" diameter so they don't seem to be applicable to the inside of a small radius. It has helped me create a better finish on the outside of my pieces and on the inside of the larger diameter pieces.

 

[TurnedAround]

Here's a small orbital sander I ran across in Highland Hardware the other day. It uses the 3 inch hook and loop pads that most good woodworking stores carry.

Larry

http://www.tools-for-woodworking.com/index.asp?PageAction=VIEWPROD&ProdID=4305

 

[MichaelMouse]

I have had a problem with sanding marks, probably from using too much pressure or stopping at 320 grit paper. My son let me borrow his random oscillating sander and many of these marks were no longer visible.

Most woods benefit little from anything beyond 320, some beyond 220. It's direction of scratch that counts. When it is parallel to the visible grain it becomes invisible, when perpendicular, an eyesore. With the contour of the work we turn preventing much in the way of parallel sanding, we go for random but uniform scratch patterns as a best compromise.

If the work's moving in one big circle and the disk in a smaller, you can randomize pretty well on the lathe. It's the pressing that gets you. Press a rotating disk at an angle into a stationary piece and it's burn or scratch. That ROS will do it as well, which is why you want to orbit up before touching the wood and remove from the wood before powering down. They have clutches in the newer models to minimize this problem, I believe. Do not press, and remember the center is not the place to get the best removal, so you'll need to be careful on the outside of things to avoid little rings of scratches.

Your revealing experience relates to the reason to cease and set if things start to shine when sanding. They're not supposed to, and if you burnish the wood, the unbottomed scratches stand out twice as bad as they would if the surface had a random scratch pattern to scatter the light more evenly. Lot of people feel frustrated when they put the first coat of finish on and "discover" a scratch pattern that they feel they must attack, if not prevent on subsequent work by four more grits. What they've done, of course is provide a directional reflection with their film, which shows some deviations in the form of sanding marks - same thing as when they heated and burnished the surface with their careless sanding pressure. Rather than go back to randomize as you would unfinished surfaces, you put the second coat on, and the scratches disappear, because they're filled in with finish to produce a smooth surface. Some people go a step further and use satin finishes, which contain scattering additives, dull and randomize the surface physically with steel wool or scatter it with wax.

So add your finish into the sanding decision and perhaps save yourself a raft of trouble and the odd buck.

 

[Mark Mandell]

2 Sanding Errors

I have had a problem with sanding marks, probably from using too much pressure or stopping at 320 grit paper. My son let me borrow his random oscillating sander and many of these marks were no longer visible. I haven't seen the random oscillating sanders in less than 5" diameter so they don't seem to be applicable to the inside of a small radius. It has helped me create a better finish on the outside of my pieces and on the inside of the larger diameter pieces.

Marc,

Excessive pressure is the main cause of most sanding problems, both turning and flat work. People seem to have gotten the impression that pressing harder makes the abrasive work better. Actually the opposite is true, especially when power sanding. As pressure increases, friction (different from abrasion) increases which creates heat. Heat first softens, then melts lignin, the binding resin in the wood, which, in turn clogs the sandpaper, defeating its purpose and making you rub harder, which, in turn . . . . .

In addition, while makers have made great gains in technology, most all abrasives have stray particles which are larger. By pressing harder, you give the larger particles more chance to interrupt the scratch pattern and leave scratches you can see as errors.

Conversely, light pressure with the abrasives allows the grains to cut better and faster while helping the abrasive surface last longer. Take it easy and you'll get more done in less time. If you're not getting the abrasive action you need, drop down a grit or two. Once you have a uniform scratch pattern in a given grit-size, moving up through the finer grits goes quickly.

Second error is that people change grits without cleaning the work surface. As sandpaper is used, it sheds some of its granules which lodge in the rough wood surface. If this grit is not removed before going to the next-finer size, you will actually be sanding with both grits, thus defeating the purpose of changing to the finer grit. While some use air to blow off a turning, I don't suggest blowing dust and abrasive particles around your shop. A good shop vac with a good brush attachment will clean the grit and dust out of the wood pores without redepositing them in your lungs. Vacuum-clean your piece every time you change paper and you'll like how much better and faster your abrasives work.

mm

 

[mrGeeze]

metabo random orbital sander

i bought the metabo mentioned in a previous post. To date I've only done a couple of bowls but i'm liking it already. Its got a small (3") head on it compared to other random orbitals so it can get inside smaller bowls. you can adjust the orbit a bit to get more agressive. so far i just leave it turned up to 11 if you know what i mean. the best thing is that it has a dust port on it. i just hook it up to the fein turbo vac & off i go. it doesn't get rid of all the dust, but it sure does get a lot of it.

its a good tool, but its not cheap. it works well and it does something to help preserve your lungs. to me its worth the money.

i recommend it

 

[Steve Worcester]

Most woods benefit little from anything beyond 320, some beyond 220. It's direction of scratch that counts.

While I vehemently disagree with the above statement, and not just because I want to sell sandpaper, I do agree with most of the rest.
The burnishing part will vary with the type of abrasive you are using and the grit. It may look shiny, but may not be burnishing.

 

[Marc Himes]

Sanding

Thanks for all the very helpful comments and suggestions. Lankford, as you can see this is a very worthwhile subject; thanks for posting it. I think for me the advice of not too much pressure and not too fast are right on. I will also look into the smaller random orbit sander mentioned. Thanks again everyone.

 

[TurnedAround]

Mark's advice is spot on. Especially the point about applying too much pressure when sanding. I power sand with the Rhino discs and have achieved the best level of success not skipping any of the grits and using finesse instead of strength.

Also, Mark's advice will lead you to get far more life from your discs. I find it helpful to keep a gum stick handy to unclog some of the heavier grits such as 60, 80, and 120. If you are not applying too much pressure while sanding, they unclog easily and will go right back to removing tool marks like they just came out of the pack.

Hope this helps, Larry

 

[pyrocasto]

While I vehemently disagree with the above statement, and not just because I want to sell sandpaper, I do agree with most of the rest.
The burnishing part will vary with the type of abrasive you are using and the grit. It may look shiny, but may not be burnishing.

I guess it depends on what wood and what you use it for. Our cabinet shop's high end cabinets have never touched anything greater than 220 for wood sanding, and get 320 between laquer coats.

Though on a piece of cedar I turned I could see a bit from 600 grit.

 

[MichaelMouse]

I guess it depends on what wood and what you use it for. Our cabinet shop's high end cabinets have never touched anything greater than 220 for wood sanding, and get 320 between laquer coats.

Though on a piece of cedar I turned I could see a bit from 600 grit.

Has to do, as I said, mostly with grain direction versus scratch direction and the possibilities for highlighting. Then there's the 20/20's that can resolve about 300 high-contrast lines per inch. Which coincides fairly closely with the 320 holes per inch in the CAMI mesh that sifts the sand for the paper of the same number.

By the time the contrast is lowered and the wood given a grain pattern, you're to the point where red oak doesn't benefit from finer than 150.

Might have been the 600 on your cedar, if the light were right and your eyes real sharp, but the odds favor a rogue from previous grits or what's worse, a scratch or dent from a fingernail on a hand trying to hold a piece of paper properly. Hate that. Especially when you press one in accidentally while roughing between coats. It's times like that I wonder if I shouldn't chew 'em to the nubs like some people.

 

[Gretch Flo]

Might have been the 600 on your cedar, if the light were right and your eyes real sharp, but the odds favor a rogue from previous grits or what's worse, a scratch or dent from a fingernail on a hand trying to hold a piece of paper properly. Hate that. Especially when you press one in accidentally while roughing between coats. It's times like that I wonder if I shouldn't chew 'em to the nubs like some people.

I Have experienced the same thing with fingernail marks, esp on bottoms of deep small bowls, and soft wood like cedar. And I even bite mine-but have been "breaking" the habit for 10 years, so they occasionally extend beyond the quick . The other place where marks show up on the finer grits with thinner paper is because of folds or kinks in the paper. Have recently gone to only 400-600 (due to all the comments on this forum), rather than 1200 as I did before, and I like the feel of a softer finish on the wood, rather than mirror-like feel. I then sometimes use 800 or 1000 (wet)to add another coat of Danish oil, and wipe off. Been experimenting with that, and I like it. Gretch

 

[DWFII]

While we're on the subject...I have always wanted to ask about how long to use a sanding disc. I sometimes will clean a disc and continue to use it...especially when sanding shellac sealer or something like that. I take a fine wire brush and "scrub" (too harsh a word) the caked shellac off the disc. Other times it's oil...such as tung oil...but if I get the surface back down to the grit, what's the harm? I realize that I probably lose some cutting power...agressiveness...as loose grit is shed but is there any other downside?


DW
In the High Desert of Central Oregon

 

[W.C. Turner]

While we're on the subject...I have always wanted to ask about how long to use a sanding disc. I sometimes will clean a disc and continue to use it...especially when sanding shellac sealer or something like that. I take a fine wire brush and "scrub" (too harsh a word) the caked shellac off the disc. Other times it's oil...such as tung oil...but if I get the surface back down to the grit, what's the harm? I realize that I probably lose some cutting power...agressiveness...as loose grit is shed but is there any other downside?


DW
In the High Desert of Central Oregon

Air compressor can blow out a tremendous amount of clog.

 

[MichaelMouse]

While we're on the subject...I have always wanted to ask about how long to use a sanding disc.

Flip answer - until it doesn't do what you want it to do. More complicated, but makes sense - go in with your eyes open. There's good news and bad news, as with most things. If you use a disk that's shed grit you do a couple of things which you may not like, such as build heat from the greater amount of contact with the backing, and become more vulnerable to rogue scratches from uneven pressure and floating grit. Open coat papers are great for softwood, for instance, and for sanding between coats, but a careless tilt under power will be more likely to leave the rogue scratch than a full coat resin-bonded.

If you use a disk which has been worn into the next grade by fragmenting most of the grit, might not be that bad, but you still have heat and the problems the rogue grit can give. Loading is always bad. Builds heat and takes time. For shellac, use a lube and/or clean with alcohol. With the possible exception of garnet paper using hide glue, shouldn't hurt the backing too much, and will soften the gunk up for removal with one of those brass-bristle flux brushes or BBQ cleaners. Stearated papers are good ways to limit finish build, but I haven't found them effective against fiber from sanding wet wood with finer grits. Detergent soaks seem to soften the buildups enough to make cleaning effective.

 

[Gretch Flo]

cleaning sanding discs.

I have one of those gum blocks (not sure of the proper name) nailed to the small table I use to set my current gouges on-just to the right of the tailstock. Just slowly run the used disc over it. The rare occasion I use it on oil, the gum block helps along with gently pushing a brush over the spinning disc. It probably would not work as well if the material has dried. Gretch

 

[DWFII]

Thanks to all who responded on cleaning the discs. I have been using both a really fine flux brush and some natural plantation gum rubber to clean the discs.

My biggest handicap in this regard is my unwillingness (like a mental block) to use discs..those oh so precious discs ...to sand shellac and oil. Seems like you get about two spins of the sander and the bowl and you've got to switch out the disc it's so clogged. I know that I should value the disc lower than the bowl and use as many as necessary but it goes against my inner Scot.

Cleaning helps a bit.


DW
In the High Desert of Central Oregon

 

[John Abt]

Try Industrial Abrasives their Ryno backed paper is extremely good. The paper wears out before the backing. You can get 1ydx1meter sheets of hook and loop for about $15 and make your own disks.. Works out to less than 9cents per disk

Do you have any contact info?

 

[woodwish]

While we are on the subject of power sanding- At the symposium I bought some of the sample sets of various grits of the mylar-backed sanding discs sold by Vince that frequents this board (VincesWoodNWonders). Seemed like good stuff when I bought it, he seems like a sincerly nice guy, and the price was right. Got home from L'ville about 1:30 AM last night and couldn't sleep (too much coffee driving home?) so I went out to the shop to play with some of my new goodies and new skills I learned. Made a quick platter out of really hard dry pecan and used Vince's dics to sand. WOW! What a great product! I have a bunch by another vendor (the "gold" stuff) that I may just throw away now, and place a bigger order with Vince. When I finished about daybreak I started to call him but figured I will wait a few days until he rests up from the sales at the symposium.

 

[TurningDog]

Do you have any contact info?

i too am an avid fan of industrial abrasives. I just cut my squares a little over size to give that soft edge wave pad feel and if I spin the the pad off and loose the velcro grip I can always reposition it this way.

http://commerce.riverweb.com:8002/shop.html