Thread: Handsanding howto

Several people asked me to re-post my hand sanding guide, so here it is. Hopefully I've written it for the last time

The purpose of handsanding is to bring a blade back to a near perfect finish, regardless of how badly damaged it was. Otherwise you might as well use a dremel and sanding discs.
Those sanding discs and drum wheels cost money, and if you have to remove bad pitting, you will spend a lot.

First of all: the ergonomics.
Hand sanding a badly damage blade can take up 10 hours or more to do it right. Holding the sandpaper in your hand, or keeping it wrapped around something is a sure way to attract tendonitis. Been there, done that, found a better way.

This is my sanding stick. It looks like crap, but it does the job well. I made it from some scrap wood, and it fits my hand just right.


The big part just fits in my hand, and I usually keep my index finger touching the thin part when I hold it. This way all tendons are in a relaxed state when I sand.
The tip is wrapped with a strip of leather. This helps distribute the pressure evenly. The wood underneath it will have some irregularities that are visible otherwise when sanding with finer grits.

Here is a pic with sandpaper on it.


If the sandpaper gets loaded with crud, I move the strip of paper a couple of mm and continue.

Now for the sanding itself.
Let me tell about the difficult part: damage removal.
This is the most tedious part of sanding, because if a blade is pitted, you have to take away a LOT of metal to remove the pitting, and you have to take away metal across the length of the blade, or you will end up with a blade that looks like some metal was scooped out of it.

Experience has tought me that the best way to remove pitting is by first sanding circular with a very low grit (80 - 120).



Circular sanding works quickest, and I think this is why: if you sand circular while going back and forth a bit, you are always sanding across (and NOT along) previous scratch lines. If you hit scratch lines from a different direction, they will come off much more easily than if you sand along the same direction continuously. Especially if there is a lot of pitting, you want metal removal to go as fast as possible.

Every now and again when the blade is completely scratched and satin looking, you sand back and forth along the blade until it is semi mirror shine. Even at high grits this is pretty easy, and you will quickly get an idea of where you're at.



Instaed of circular sanding you could also speed up metal removal by sanding first from spipne to edge, and then from heel to toe, and then from spine to edge again, but sanding from spine to edge is uncomfortable because the distance is so short.

As soon as all the damage is gone you are ready to go up in grit. Don't go up sooner because low grit is the fastest way to remove damage. Don't even think about sanding away left over pits with 400 grit paper, no matter how fed up you are with low grit sanding.

As soon as I am satisfied that the damage is gone, I use the following progression:
150 180 240 320 400 600 1000 1200 1500 2000

At 240 I change my sanding method.
From then onwards I will do 1 grit from edge to spine until all the previous scratch lines are gone. Then I go to the next grit and go from heel to toe until all previous scratch lines are gone.

If you removed all the pitting with the low grit, then from 400 onwards it takes very little time to progress.

By the time you hit 2000, the blade will be mirror shining, and ready for the dremel, buffing wheel and polishing compound.

Nice howto, thanks for putting this back up

Nice info to read, I have learned a lot on sanding my blade.

Can you tell me about edge placement during the sanding process.

Do I have to protect the edge or just try to keep it flat on lets say a thick peice of leather??

Jacques

Thanks for the great tutorial Bruno.I was lucky enough to have read the original and have been putting it to great use.

I have a norton sized stone that I cut from a litography stone, which is lime I think.
It is flat, and it has the nice property that you can hit it with an edge withot damaging or blunting that edge.

Anyway, if you keep the blade flat on the stone, then there is no problem.
If you try to protect it with tape, then there is a part which you can't sand.

It should be obvious that you don't hone a blade until after the sanding and the polishing.
If an edge is a bit nicked, then there is even a chance that the nicks will be partially gone afterwards, because when you sand from edge to spine and back, you will sand the very edge as well.

Btw a VERY important additional tip: when you are done sanding for the night, rub the blade with rubbing alcohol to get rid of grease and dirt.
If you don't, then you might get a very nasty discovery if you lay it away for a week. And this is especially tru at the low grit stage, because those deep scratches attrackt moisture and grease very much.
I learned this the hard way.

Just a question. Any reason why a sanding block like this: http://www.rockler.com/product.cfm?page=16762 could *not* be used? Of course it's got a wider area but it would seem like that would help in terms of keeping the frame material removal even.

I ask because as a hobbyist woodworker (among the many other things I waste time doing....) I have plenty of tools, and am wondering if they might be useful in restor projects....

TIA!

Thanks for the info.

John

You could, I suppose. In fact why don't you just try it out.
One thing I can imagine is that it would be very easy to put too much pressure on a full hollow.

Also for curved razor you might have problems with the curvature, and it is also a lot harder to work on small surfaces.

And finally: mounting the sandpaper might be a problem. You can only sand with the tip area, but as soon as that area of the paper is loaded, you cannot shift the paper anymore. Whereas with my sanding stick, I can use all of the sanding surface.

Personally I don't think it will work well, or be easy to handle, but the best way to find out is to do it. Trial and error is the best way to learn.
If you have such a thing lying around, give it a try and post back.
For all I know I might be totally wrong about this.

I appreciate your processs and it appears more effective than mine but 10 hours of hand sanding seems pretty high to me. Note that my own process currently takes longer and does not as good a result so I'm not just trashing yours because I have a better solution.

BUT
I would hope that the coarse work could be speeded up
as well as the polishing work once buffed to 2000 grit.

Can anyone offer up process improvements to reduce the time involved in refurbishing a blade RECOGNIZING that power tools increase the chances of damaging the blade substantially and might not be appropriate for real collectables or high end blades.

- Bob

Most of the time is spent on the low grit stages.
The 120 grit takes a long time to get rid of pitting and damage.
Then next grit takes a long time because the blade will be deeply scratched at that point.

But from 400 onwards, if goes quicker and quicker, since you only have to get rid of the sanding scratches of the previous grit.
th 2000 stage only takes < 10 min per blade face.

Power tools can increase your speed, but the time intensive part -> 120 is where a power tool could do a lot of damage before you even know what happened.

I am not a luddite. If anyone knows a way to safely speed up the process then please tell us how. The low grit stage is usually where I think 'Why TF am I doing this'

This is also the reason I don't base the price for my restorations on the number of hours spent. I go for perfection, and it takes as long as it takes.

10 hours is a long time, but the results are stunning, and the process is safe.

Additionally, I can do this while sitting in the couch next to my wife, instead of in the garage where I can work with power tools.