# Used sandpaper



## m.n.j.chell (May 12, 2016)

I've got some questions about sandpaper. 
For background, I've got an 80 grit belt on my sander, but it's worn down to the point where it's sanding like 200. I mean, seriously smooth finish on the wood I am sanding.

My questions: 
How long do you guys use a belt? 
Do you use it as a higher grade sandpaper after it's worn down some?
At what point do you consider a sandpaper useless?


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## Steve Neul (Sep 2, 2011)

You can't really used worn out paper for a finer grit. Not all the grit will be worn out and you would end up making some 80 grit scratches in the wood.


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## GeorgeC (Jul 30, 2008)

Used sandpaper should be trashed when YOU no longer feel that it is capable of its original purpose. It has NO secondary purpose.

George


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## Brian T. (Dec 19, 2012)

Agreed. It's junk. To me, grit size implies a result that I can predict.
Sanding wood/plastic/metal edges or using 1,000 for sharpening, all the same.
Steve describes it well: you have a mix of grits on worn papers.
In a sharpening or other sanding sequence, when you fail to see progress, time for new.


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## woodnthings (Jan 24, 2009)

*I see this issue*

Let's say it feels like it's worn down to 220, and all of a sudden in the middle of your super smooth finish and old grit raises it's ugly head and makes new scratches all over your super smooth surface ..... :crying2:


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## Toolman50 (Mar 22, 2015)

Unused sanding belts have a shelf life. The seam where the belt was originally glued together breaks. 
These belts can be cut and used for hand sanding. They're very durable when used for hand sanding. 
I've learned not to buy a 5 year supply of sanding belts.


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## Jim Frye (Aug 24, 2016)

Used sandpaper has a use, but not for wood working. I keep old sheets around for outside use like rust abrasion or the like. Sandpaper costs a lot less than the wood you are working on. All it takes is for one piece of 80 grit to put a scratch in a surface you think you've taken past 180 grit that you'll see as soon as you apply the first coat of finish.


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## epicfail48 (Mar 27, 2014)

I pitch sandpaper as soon as it I feel it stop cutting efficiently. Its difficult to put into words, but pretty easy to feel. Some of the best advise I've ever heard regarding like sandpaper is "use it like someone else is paying for it". Life is too bloody short to waste time with dull sandpaper. Papers cheap, time isn't.

On the topic, I'd recommend against using dull paper as a higher grit. Reason being, as the grit wears it doesn't get smaller, it just stops cutting and starts rubbing. The wood isn't smoother because the paper is getting finer, its just getting burnished, which can interfere with the adhesion of stains and finishes. There's also the very, very high risk of burning. 

Slightly off topic, but despite the aforementioned best advise I've been given, I didn't believe it much until I started working with metal. Dull paper in wood will end with a result that can trick you into thinking its still cutting okay. Dull paper in hardened steel will lead to a knife and a wall having a high-velocity interaction after sanding on it for a half hour with no bloody effect

Completely unrelated, but I now budget 2 fresh sheets of paper in each grit for every knife I make. The broken window in my workspace has absolutely no bearing on that decision


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## allpurpose (Mar 24, 2016)

Back in my youth during the one and only wood shop class I ever took the instructor acted as if sandpaper was made of gold that he personally had to mine, refine then set each particle individually onto paper he made from trees he personally had to cut down and drag down from the sides of mountains on his back. So, the little napkin holder we all had to make for our mothers from little pieces of rock maple were smoothed with the most precious of 4"x4" piece of sandpaper ever known to humankind...FAR MORE precious than the little napkin holders.
Despite all that my mom loved the little napkin holder that I hated more than any single project I ever finished. 
My mother came from the same school of never throw away anything if there will ever be any possible use for it ever ever ever.. 
And my kids wondered why I was such a stingy prick about throwing things away.. lol
Come to think about it those of you whose parents were raised during the great depression should also know this story word for word as well.
I buy sandpaper in bulk now usually, but still find it difficult to bring myself to throwing out the odd piece. 
The stuff I won't hesitate to toss is the kind used on a random orbit sander. Years of auto body work taught me not to fool with it beyond the first few minutes of sanding.


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## Brian T. (Dec 19, 2012)

Does everybody know that, within reason, you can clean sandpaper? Sanding drums in my drill press, the sanding belts on a hand-sanding finger, etc.

The sand paper loads up with dust. Seems to cut less so many people push harder. The friction heat fuses the dust into the papers. Don't.
Instead, get a crepe rubber stick like sold by Lee Valley. Works like a giant eraser and pulls all the dust out of the paper. It is amazing how long good
sandpaper will actually last when you clean it. Use the edge of an old wrecked flip-flop/thong footwear. Just about as good.

Stone wheel in my drill press. I am cutting and shaping abalone shell pieces for inlay in wood carvings. The stone loads up with shell dust really quickly.
A quick wipe with the rubber stick on the running stone and back to shaping. Without it, I'd guess that I would stuff up about $100 worth of stones
to finish a single 1" circle of shell. I'm still on stone wheel #1 from 5? years ago. Shell, maybe 20-25 shaped pieces.
Yes, my shell dust collecting system works extremely well.


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## WeebyWoodWorker (Jun 11, 2017)

I use my belts a bit more that I probably should but I do always keep them. I tear them up into strips and use them when I polish my knife blades before them finally tossing them as steel dust ruins the paper completely. Even when sandpaper won't really do that much to wood I find that it still can have some use when used on steel and other metals. Now purely from a woodworking point of view, I guess you could use old sandpaper to sharpen chisels and such but it would be drastically more effective to use "fresh" sandpaper instead. So old sandpaper is kinda useless for most people. If it's not plastic I guess you could use it to start fires, but that's what plane shaving are for. SO sadly just toss it I guess.


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## allpurpose (Mar 24, 2016)

I'm kind of glad I looked at this thread again because it made me realize that my 80 g belt is really really really really REALLY close to useless other than perhaps as a traction surface for the bed of my pickup and even then pretty useless because the previous owner put in one of those crappy plastic bed liners..well, not really crappy..I just don't like them..


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## ejmolitor37 (Sep 17, 2017)

I work at 3M, so most sand paper once it's not cutting at the grit it should as mentioned it's done. Sand paper has different little particles in it that create the abrasive. Big pieces and smaller pieces. The exception is trizact made by 3m all the grit particles are same size by my understanding. Or micron sheets or lapping film. Those also share same size grit. Hope this helps.

Sent from my SM-J320R4 using Tapatalk


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## Catpower (Jan 11, 2016)

I did wear out a new 6x186 100 grit belt on my stroke sander in about 3 minutes

I was thinking epoxy would sand off fairly easy on an end grain cutting board I was making, I was wrong LOL


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## Cowboy18 (Aug 21, 2017)

Catpower said:


> I did wear out a new 6x186 100 grit belt on my stroke sander in about 3 minutes
> 
> I was thinking epoxy would sand off fairly easy on an end grain cutting board I was making, I was wrong LOL



I use my grinder with 80 grit resin disk to take 90% of the epoxy off before breaking out the sander. Must have great control of the grinder or you'll make gouges in the wood that will cause sanding nightmares. Wear a mask and get a mans grip on that grinder, and you'll be done in 20% of the time it would take with a sander.


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## Catpower (Jan 11, 2016)

Cowboy18 said:


> I use my grinder with 80 grit resin disk to take 90% of the epoxy off before breaking out the sander. Must have great control of the grinder or you'll make gouges in the wood that will cause sanding nightmares. Wear a mask and get a mans grip on that grinder, and you'll be done in 20% of the time it would take with a sander.



After it plugged the 100 grit, I put in a 60 grit, no problems but you really have to watch it, it will take off wood as fast as a planer


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## Pineknot_86 (Feb 19, 2016)

GeorgeC said:


> Used sandpaper should be trashed when YOU no longer feel that it is capable of its original purpose. It has NO secondary purpose.
> 
> George


I was at a woodturning symposium. One fellow echoed what GeorgeC said. Sandpaper is too cheap to use beyond its usefulness! Buy it in bulk if you can. I bought a stack of 220 grit for a few bucks at our woodturning meeting last month.


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## epicfail48 (Mar 27, 2014)

Catpower said:


> I did wear out a new 6x186 100 grit belt on my stroke sander in about 3 minutes
> 
> I was thinking epoxy would sand off fairly easy on an end grain cutting board I was making, I was wrong LOL


To be fair to the belt, you didn't wear it out, just clogged it. Cleaning the belt will make it work like new, if a rubber block doesn't take it out sanding something hard, like a bar of steel, does a surprisingly good job.

If the abrasive on the belt is actually worn you either have a crappy belt or the mother of all epoxies


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## Catpower (Jan 11, 2016)

epicfail48 said:


> To be fair to the belt, you didn't wear it out, just clogged it. Cleaning the belt will make it work like new, if a rubber block doesn't take it out sanding something hard, like a bar of steel, does a surprisingly good job.
> 
> If the abrasive on the belt is actually worn you either have a crappy belt or the mother of all epoxies


Yeah it was just plugged up, the belt "eraser" wouldn't even clean it


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## epicfail48 (Mar 27, 2014)

Catpower said:


> Yeah it was just plugged up, the belt "eraser" wouldn't even clean it


Have that happen with my grinder belts from time to time. If you can manage to get a bar of steel to touch one of the wheels it does a pretty good job scraping all the crap out and exposing fresh grip. Quick and easy 30 seconds to save a belt, you know?


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## Larry42 (Jan 10, 2014)

Most of the above comments are right on. The grit gets warn and is no longer sharp, doesn't cut and then burnishes, heats etc. Use P graded belts, they have more consistent grit size. Use open coat rather than closed coat for wood. Don't skip grits and things go much faster. Cheap sand paper/belts are not a good deal. Poor adhesive, cheap paper or cloth, irregular grit sizing, bad joints.....


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