Thread: Advice on shaping bone scales, please

Champ Body File Sand Paper Sheets - 2 3/4" x 17 1/2" This type of paper is the cats meow for flattening things. (bones, burls, even hones). The paper comes in various grits with an adhesive back and is long. I start the 36 grit and stick to a table top. After using this you can put full or half sheets of a finer grades of paper on the table and rub the bone on them to flatten them.

I have to second what PDobson said about backing up the paper. That is a great piece of advice.

The local auto body paint/supply store sales it by the individual sheet.

Charlie

I, too, use adhesive backed sandpaper for flattening, well, everything. I start at 80x and move up to 220x. The stuff I use is by 3M and it's available through luthier supply catalogs. It's not just good for flattening. You can even use it to match radii like a bridge on a curved-top guitar.

Phillip

Originally Posted by pixelfixed

dremels IMO are somewhat useless tools that can cause alot of damage.

Dremels are not at all useless tools. I use mine for all sorts of work such as, buffing small parts that may go into the razor, cutting small pieces of tubing, cutting out inlays, scribing small design work, and I have the drill press attachment and as I don't have a lot of room for an actual drill press the dremel press is how I drill pin holes.

You will however notice that I didn't mention shaping scales in any of that because when it comes to shaping scales dremels IMO are somewhat useless tools that can cause a lot of damage.

On my first scales I did use the dremel on the drill press attachment, set really low, like a rotary sander to rough shape in the scales; but the finish work and shaping was all by hand sanding.

As for the sticky back sandpaper some have posted, I usually just use regular sandpaper cut into strips and double sided tape to get a similar effect. Does the actual sticky back paper have some quality that I'm not able to replicate with my method?

I agree that the Dremel tool is a very useful one. The cutting discs are excellent for cutting out, in sheet bone up to about 4mm. thick, a shape with a shallow curve. Much the same would no doubt apply with the little diamond wheels which are now available for a fraction of what they used to cost, and without the risk of breakage.

The abrasive sleeves are good for rough shaping, but extremely liable to bite too deep as you come anywhere near the finished shape. For this sandpaper glued to a backing which will curve in one direction, such as very thin aeromodellers' plywood, is much better. It doesn't matter how you achieve that - self-adhesive, double-sided tape, PVA or dabs of superglue are all good. Start very coarse, and water, which is such a help on metal, is likely to produce clogging in bone.

The little Dremel sanding discs can be very good for finishing work, but there is a tendency for the screw-head, which is a tiny two-toothed circular saw to abrade the work. I found adequate strength, with flexibility enough to stop edges digging in, was achieved by gluing two discs back to back, when centrifugal force tended to keep them flat. I also have (and have almost worn out) a sort of rubber arbor onto which a sanding disc or piece of sandpaper can be glued, with no central screw. It is very good, but I don't know whether Dremel made it, or somebody else. There is also a sort of tap washer which comes with a short stem, 3/8in. diameter, at the rear. I think I can make some sort of tubular mandrel to use these interchangeably, or make one up from flat tap washers (one large and the others small) superglued to a 1/8in. shaft.

One of these, flexible and smaller than the ordinary sanding disc, should also be good for smoothing the hollow ground surface of a blade, without reaching the edge.

I've found tea or leather dyes good for faking up an old razor, but liable to come out too mottled for making one as new. In particular any roughness of the surface is liable to take the dye much better than a smooth surface. So you need to get it all evenly smooth before committing yourself. You need directional light for this, in something white, by a point source some distance away.

A really sharp scraper is also good on bone. The kind of craft knife where you break off the last 3/8in. when it gets blunt is good for this, using not the sharp edge, but the broken one. If you hanker after the Stone Age you can also get as many scrapers as you will ever need, with varying curvature, by wrapping a piece of glass in newspaper, and stepping on it.

Originally Posted by Peasel

Once the scale pieces are cut from the bone, I was going to use a dremel sanding wheel to make rough adjustments in size and shape.

For fine shaping and polishing, I'm assuming the same type of sandpaper used on the blades can be used on the bone. What grit do most people start with? End with?

If you want a glass-like finish you may need to go a little higher in grit than you do on the blade. Depends on you finishing process for the blades (e.g. do you follow up with black and green cutting/polishing compounds with your dremel after sanding, or polishing pastes, etc.)...

In any case, I too work only with hand tools and a dremel (due to living space restrictions) and find Micro Mesh to be a wonderful and indispensable tool for getting a really nice, polished finish on scales (and blades as well if I go the sandpaper route instead of using greaseless and cutting compounds with the dremel). The shine really starts to come out at the 6000 grit Mesh and is smooth as glass after the 12000 grit Mesh.

As for getting waviness when using a dremel sanding drum to shape the thin edges of the scales, I know what you mean. I think you'll find that if you leave a little extra material when shaping with the dremel, then use a block with your sandpaper and micro mesh to finish by hand, you'll be able to work down through the lumps and end with a nice even surface.

Good luck and let us know how the project goes.

[QUOTE=Caledonian;793365]Start very coarse, and water, which is such a help on metal, is likely to produce clogging in bone.
QUOTE]

This is slightly off topic, and I feel silly asking now (after a couple a resto's under my belt), but you get the blade moist while sanding?! Makes it easier?! I know that the paper is "Wet/Dry" but I just defaulted to trying to avoid getting metal wet.

I hand sand, only, while restoring. Getting the metal moist while sanding will help?

Originally Posted by Peasel

I hand sand, only, while restoring. Getting the metal moist while sanding will help?

It seems to IME. I read somewhere that water helps keep the grit clear of debris so it will cut better for longer. I've tried both wet and dry and wet seemed better to me. It was also easier to see how the job was progressing.

wet doesn't mean you need to use water. I use wd40 in place of water when I sand the metal parts, all the benefits of wet without using water, although I'm sure that isn't a good idea on the bone. Yet there are tons of threads about metal here so lets swing back to topic...

so, what does power tools on bone smell like, is it as bad as horn?

Originally Posted by TheBaron

...so, what does power tools on bone smell like, is it as bad as horn?

It is a strong, natural smell. Not really the burning hair of horn though.

A dental hygienist neighbor of mine, stopped by once while working bone and said it smelled like I was drilling teeth.

Originally Posted by TheBaron

As for the sticky back sandpaper some have posted, I usually just use regular sandpaper cut into strips and double sided tape to get a similar effect. Does the actual sticky back paper have some quality that I'm not able to replicate with my method?

I use both methods. The advantage to the adhesive-backed sandpaper is width. The paper I use is three inches wide. That would take a lot of tape to cover. Also, any place where the tape overlaps or gaps will introduce error, (your flatness will vary by the thickness of the tape). Another good option is to use spray adhesive to mount sheets of sandpaper to you surface plate; it's just a little messy.

Phillip