Sanding fast or slow?

[GC]

Hi All,

Could you please give me your wisdom on sanding on the lathe.
I've heard it should be with the lathe speed slow to give the paper time to cut the wood, but also heard fast gets it done faster.

Which is it?

Thanks in advance

GC

[Skew ChiDAMN!!]

SLOW! Most definitely. :yes:

Sandpaper is designed to work at relatively low speeds... even a belt-sander doesn't operate as fast as most turning is done. Fast speeds only clogs the paper faster, reducing it's efficiency and creating excess heat... and excess heat damages both the paper and wood.

Consequently, sanding at slow speeds usually gets the job done faster!

[jefferson]

All that my "learned" friend said above. Well, Andy and I are probably more in a master-pupil relationship, but never mind.

Aside from slowing the speed down, watch for heat. As will all woodworking, a good rule is 50% turning (or joinery) and 50% for finishing - mostly sanding, filling etc.

And the harder the wood, the more you need to watch for heat. Our hardwoods DO NOT LIKE HEAT. Use your fingers. Hot fingers means you need to stop and take a break.

Faster sanding speed = less control = cracking.

All of this new writing style of mine is to avoid being verbose. (Is this one OK, Calm?)

And I will not re-read to check for typos, so don't bother with any criticism. :D:D

[powderpost]

Large diameter, slow..... smaller diameter a bit faster.
Jim

[tea lady]

Then there is "" fast and "normal" fast.:doh: :rolleyes:

[Texian]

Pressure makes heat. Faster with light pressure, slower with heavier pressure. Sometimes zero rpm for grinding out a bad bit of tearout. But then I'm the only one that gets tearout.

[brendan stemp]

All good advice. I tend to slow the lathe down for sanding but also think Texian's advice is worth considering. The pressure one uses on the paper is just as important as the speed. So, just like grinding tools on a spark grinder, light pressure is what is needed when sanding. Let the paper do the work.

[madcraft]

Definitely slow , I normally sand around the 300 to 500 rpm mark, with the occasional with the grain rub {while stopped this allows me to cool it down and clear the paper and the paper seems to last longer } Micromesh is always slow and wet { I think it gets a smoother finish that way } the only time I fast sand/polish is with EEE from Ubeut or Tripoli Powder . my idea is that I don't really care how long it takes . I want a finish I am happy with

[BobL]

Here is an instructive table table that shows the linear speeds in m/s for different diameter objects turning at different RPMs.

http://www.woodworkforums.com/attachment.php?attachmentid=120503&stc=1&d=1256597555

Belt sanders generally operate with linear speeds of between 4 and 8 m/s linear speeds. The figures with red backgrounds show the RPM/diameters that definitely exceed the belt sander values. But don't forget that most belt sanders have a very large areas of paper and a mechanism to remove the dust so the paper doesn't clog. If using a small area of paper this means you need to reduce the rpm even further.

If in doubt just start on the slowest speed and work upwards.

[hughie]

....... slow is fine but how about using a inertia sander? :U They depend on the drive of the work piece to effect the sanding process. I find that they need speed, in fact all the more the merrier.

One of the current design trends is toward open type of sand paper ie Astra dot, single and double etc. As far a I can see this is to open up the sandpaper to allow self cleaning to be more effective.

I use Noritake sand paper with its single and double dot design, in lower grades ie 60-80-120 etc as speed is required for my inertia sanders, the cleaning aspect is well taken care of due to in part the dot design and the spinning action of the sander.

On higher grades with out the dot design clogging is definitely a issue. But again the action of the sander greatly assists in the cleaning of the paper, so I tend to do it all at speeds over 500rpm.

Power sanding I drop the speed down or even stop the lathe and rock the job back and forth as I sand . But the sander it self is going at high speed especially if your following the Raffan method of using a 4"disc grinder.However most of my power sanding is done with a variable speed pistol drill of which I vary the speed according the problem at hand. But still with a tendency toward higher speeds for faster removal.


These days I rarely do any hand sanding on the lathe. Using higher grades, say 320 and up power sanding and inertia sanding will produce very good results, better I find than any other method I use.

[Skew ChiDAMN!!]

....... slow is fine but how about using a inertia sander? :U They depend on the drive of the work piece to effect the sanding process. I find that they need speed, in fact all the more the merrier.

Oooer! There's always someone who wants to throw a spanner in the works! :p

But really an inertia sander is sanding at much slower speeds than it appears... It's sanding not at the feet/yards/miles per minute the timber is turning, but at the rate of the angular displacement of the head in relation to the timber. If you do the maths, it's quite slow... about belt-sander speeds.


All good advice. I tend to slow the lathe down for sanding but also think Texian's advice is worth considering. The pressure one uses on the paper is just as important as the speed. So, just like grinding tools on a spark grinder, light pressure is what is needed when sanding. Let the paper do the work.

:yes: I try to never press on where the paper is cutting. When possible, I hold the two ends and sand using the middle, or I fold the paper to stiffen it up and use it like a stationary flap sander.

[joe greiner]

Pressing on the paper at the point of contact can clog the paper right quick, with the paper stationary. I've been experimenting with drawing the paper under the point of contact, with light finger or thumb pressure, so it acts a little like a miniature belt sander. It seems to work better this way, at least sometimes.

Cheers,
Joe

[Manuka Jock]

Ok guys , what direction to sand ?

uphill , downhill, center to edge , edge to center , up and down , side to side ... ? :rolleyes:

Same direction as with the tools ?

[NeilS]

The only time I hand sand is on spindle work (which I don't do very often), so will leave the comments on hand sanding to those with more experience with that.

My experience is mainly with power sanding on bowls and the like. My preference is to wind the speed of the lathe up as fast as the piece will safely go and to run the power sander on full revs, BUT work with a light touch. The relative speed would be about 3,000-5,000rpm.

Unlike hand sanding, the area of contact between the sandpaper and wood is constantly changing and as a result there is less heat buildup than might be expected. The air cooling effect of the spinning disk probably also helps.

I can only remember causing fine heat cracks once, in a piece of Flinders Ranges Corkwood (Hakea ednieana), which must have been still green. Should have left it another five years, but it was such lovely wood I couldn't resist it any longer and it did make a rather specy exhibition piece. Don't think anyone noticed the few fine cracks...:).

Some woods are more inclined to clog abrasives than others. If they do, I just clamp one of those abrasive rubbers near the lathe and power sand that as required.

.....

[GC]

Nice one Jock, another dimension......:wink:

GC

[rsser]

Sanding is a pox and I go in as hard and fast as possible. Have only had one failure that could be attributable to excessive heat.

I like doing the first grit or two of a bowl inside by hand. It's harder to mess up the line if you're feeling it. Used to use Garnet paper (Norton? orange stuff) which cuts aggressively and doesn't clog too quickly. Bit hard to find now.
...

Neil, I'd wondered about the turning properties of that Corkwood. Saw a good deal of it on the recent trip to the centre and the Flinders R.

[Calm]

I'm with Ern on this - only thing i find is change paper often - old/blunt/worn out paper creates a lot of heat. When you run your fingers on the paper and think it still has some bite - it probably doesnt.

I usually sand at less speed than i turn but with EVS i only turn down a couple of numbers (nowhere near the speed Bobl chart shows)

Cheers

[hughie]

But really an inertia sander is sanding at much slower speeds than it appears... It's sanding not at the feet/yards/miles per minute the timber is turning, but at the rate of the angular displacement of the head in relation to the timber. If you do the maths, it's quite slow... about belt-sander speeds.


But then that still leaves my power sanding.....:U and at the speed I am running it would be very close if not in the purple on the scale,around 1500 rpm with a 75mm dia disc plus what ever the lathe is doing at the time

Sanding is a pain so, as fast as I can get it over with the better. Speed = time :U

[issatree]

Hi Skew,
Although I mainly turn smallish stuff, My Lathe runs at 3000rpm, & I sand at the same. Never ever had a problem. As for dust filling the Paper, it certainly doesn't with my
Hermes 406 J Flex, Blue with yellow cloth backing.

TTIT, sent me some Rhyno Wet Redline, ( used in the car crash repair industry) & it is a wet & dry paper. Made in Portugal by Indasa.

I've given this stuff a real workout & I can't fault it. It is not used in Vic.

It looks as though it is clogged up, but I give it a wipe on my White Chem. Suit, & it comes back like I had never used it. I can't speak highly enough for it, & it lasts.

I almost certain I could not get a better finish than they way I do it, with speed & polish.

I think it is horses for courses, what ever turns you on, what ever ?.
Regards,
issatree.

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[jefferson]

The only time I hand sand is on spindle work (which I don't do very often), so will leave the comments on hand sanding to those with more experience with that.


.....


Geez, Neil, I read the first sentence and nearly fell off the chair! :oo:

Someone who doesn't sand????

Then I got into the power sanding stuff - and I felt much better.

Up at Prossie this weekend. I'll ask around for some granite for you to turn WITHOUT sanding..... :D:D:D

[NeilS]

Geez, Neil, I read the first sentence and nearly fell off the chair! :oo:

Someone who doesn't sand????

Of course I have to sand, Jeff, and especially my spindle work. It's just that I don't do much spindle work so am not confident in giving any advice about hand sanding with so many others on the forum who can give sound advice.

Come to think of it, the last bit of spindle work I did was one of those fiddly little finials that everyone was doing a month or so ago. Started and finished with 800 grit, but that was on Inland Rosewood. Not exactly orthodox!

BTW, I did complete a bowl once without any sanding. More an exercise in how far I could take scraping than can I avoid sanding. Partly inspired by traditional Japanese carpenters who never sand, but plane to a polished finish. Took twice as long to scrape to a near polished finish than if I had sanded it. Needless to say I abandoned the technique after that bowl. Here it is in this post (http://www.woodworkforums.com/f8/essential-tools-your-type-turning-105991/index3.html#post1047190), and as you can see the scape marks are still there, just.

To Jeff, and all the other Forum Members that are attending, have fun in Prossie.

.....

[GC]

ok I'm off to the shed to slow the lathe down and use new paper.............
will let you know

GC

[rsser]

Hmm, well I've been struggling with a gummy timber - Deodar - and no matter what I do the paper gums up in seconds with power sanding. This is going slow and light to keep the heat to a min.

Anyone got any tips?

I've sealed the wood with weak shellac. That's no better, maybe even worse.

80 grit goes OK but anything higher ... :no:

Astra single dot ( I think it is ) works best out of the collection I've got but it's still a matter of seconds :shrug:

[rsser]

BTW, I'm looking at getting in some disc exotica. No, not audio :p

White Rhyno is available (http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=packard&Category_Code=snding-adiscs-vel-whirhy).

3M Cubitron (ceramic coating)

Even diamond coated is avail. in the US at a mere $18 ea.

http://thesandingglove.com/2009-Catalog-The-Sanding-Glove.pdf

[Manuka Jock]

Hmm, well I've been struggling with a gummy timber - Deodar - and no matter what I do the paper gums up in seconds with power sanding. This is going slow and light to keep the heat to a min.

Anyone got any tips?

I've sealed the wood with weak shellac. That's no better, maybe even worse.

80 grit goes OK but anything higher ... :no:

Astra single dot ( I think it is ) works best out of the collection I've got but it's still a matter of seconds :shrug:

Ern, how would wet sanding go on wood that gummy ?

[rsser]

I'll give it a go. Thanks MJ.

[Chipman]

Earn,

What if you clean the wood first? Try some acetone?

Regards,

Chipman

[rsser]

That's another good idea. Thanks.

[NeilS]

Hmm, well I've been struggling with a gummy timber - Deodar - and no matter what I do the paper gums up in seconds with power sanding.

Sorry, no magic solutions that I know of, Ern.

The two methods I have used are:

Clamp one of those large abrasive rubbers* somewhere handy on the lathe and alternate between power sanding the wood and the rubber.
Some gums will dry out quickly and then fall off more readily when dry, in which case I go through a batch of disks until they are all clogged, then start again with the first disk, by which time it has dried out. More convenient if you have lots of pads.
I prefer the first method, if it works.

[thefixer]

Hmmm, I must be the only one here that enjoys sanding on the lathe. I guess it's because having been a spray painter for 15 years and spending hours and hours hand sanding the undercoat and top coats on cars that holding a piece of paper against a spinning piece of timber is a breeze. If every turner could sand back a couple of fully resprayed cars with ultra fine wet and dry by hand then I'm sure he/she would appreciate how easy it is to sand on a lathe. Any way I reckon sanding is quite relaxing. Just my two bobs worth:)

[rsser]

Shorty, feel free to drop in ... got enough to make you really relaxed!

Neil, yeah, have been using the rubber stick. Spend more time at it than sanding. Hadn't thought about waiting for the 'plaque' to get brittle.

I've just tried MJ's water sanding idea and though the abrasive clogs as quickly the resulting 'paste' is much quicker to remove with the rubber stick.

Will try the acetone idea next.

That's four bowls done.

Don't you get sick of the smell of some timbers? This stuff is a cross between wet hessian and stale pee.

[rsser]

Acetone treatment: yep, slowed down the clogging compared to no treatment, but also slower to get the resin off compared to water sanding.

[mkemila]

Hey All,

I have two cents left that I can throw in......one consideration is what type of wood you are sanding and what heat does to the dust you are creating.....too much heat on maple (for example) will start to burnish your wood making any further finishing difficult if not impossible to adhere. I was lucky enough to hear Jon Eakes speak about sanding and sanding products at my local Lee Valley....that man is an encyclopedia!!

[rsser]

True nuff.

You don't want a polished finish off the abrasive if you're going to apply a surface sealer.

But I'm a DO man.

Except when I'm a sanding sealer and wax man :-

[brendan stemp]

Gday Ern, I reckon wet sanding is the way to go. I place a towel on the lathe bed under the piece I am sanding and then a ice cream container half full of water on top of the towel. When sanding the wood is kept quite wet with me dipping the sandpaper regularly into the water and working my way throught the grits. This should work. A bit messy with water spraying everywhere but its only water!

[rsser]

Ta for the tips Brendan.

Yeah, thought I'd wiped the bed clean after that effort but 2 hours later there were brown spots dammit.

The only other time I've wet sanded was with Blackwood. It seemed to muddy the figure a little. It wasn't highly figured; just contrast between early and late growth.

But I'll persist. Sure keeps the dust down.

[jefferson]

Of course I have to sand, Jeff, and especially my spindle work. It's just that I don't do much spindle work so am not confident in giving any advice about hand sanding with so many others on the forum who can give sound advice.

Come to think of it, the last bit of spindle work I did was one of those fiddly little finials that everyone was doing a month or so ago. Started and finished with 800 grit, but that was on Inland Rosewood. Not exactly orthodox!

BTW, I did complete a bowl once without any sanding. More an exercise in how far I could take scraping than can I avoid sanding. Partly inspired by traditional Japanese carpenters who never sand, but plane to a polished finish. Took twice as long to scrape to a near polished finish than if I had sanded it. Needless to say I abandoned the technique after that bowl. Here it is in this post (http://www.woodworkforums.com/f8/essential-tools-your-type-turning-105991/index3.html#post1047190), and as you can see the scape marks are still there, just.

To Jeff, and all the other Forum Members that are attending, have fun in Prossie.

.....

Neil, I haven't been ignoring you..... Just trying to catch up after a short absence in FNQ.

Up at Proserpine, I made one small piece out of Acacia Un-turnable.

(I pleaded with Cliff for some wood that Ken W. couldn't turn. All he could come up with was Boree? (right, Cliff?).

Anyway, Ken W turned it no problems. Same for me, after got me cutting downhill..... :B

And I did try to scrape without sanding.... Almost worked. Touched up with some 600 and 800 grit W & D and the result was great.

Moral to the story: - you sand more on open / porous/ soft wood. Use the scraper on the hard stuff and you sand less.

And, on the issue of scraping, Ken W. insisted that I use his radical 45 degree scraper for the job. kindly offered his less aggressive scraper.....

They argued for a little while..... Until Ken explained to that I was scared of the tool. After that, the buggers insisted that I should use the radical scraper..... :rolleyes:

A nice pair, aren't they?

No catches thankfully - and another lesson learnt.

[RETIRED]

Neil, I haven't been ignoring you..... Just trying to catch up after a short absence in FNQ.

Up at Proserpine, I made one small piece out of Acacia Un-turnable.

(I pleaded with Cliff for some wood that Ken W. couldn't turn. All he could come up with was Boree? (right, Cliff?).

Anyway, Ken W turned it no problems. Same for me, after got me cutting downhill..... :B

And I did try to scrape without sanding.... Almost worked. Touched up with some 600 and 800 grit W & D and the result was great.

Moral to the story: - you sand more on open / porous/ soft wood. Use the scraper on the hard stuff and you sand less.

And, on the issue of scraping, Ken W. insisted that I use his radical 45 degree scraper for the job. kindly offered his less aggressive scraper.....

They argued for a little while..... Until Ken explained to that I was scared of the tool. After that, the buggers insisted that I should use the radical scraper..... :rolleyes:

A nice pair, aren't they?

No catches thankfully - and another lesson learnt.That's what friends are for.:wink::D

[jefferson]

Good friends, too, . :2tsup::2tsup::2tsup: