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How To Polish Agatized Dinosaur Gem Bone For Newbies?

gem bone agatized dinosaur bone

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#1 AJ Plai

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Posted 03 June 2013 - 11:37 AM

Hi, I am looking to learn more about the skills and equipment and substances that are commonly used in prepping and polishing rough agatized dinosaur bones that will bring out the colors intensity in ways that you achieve when you wet the bone surface when its in unpolished state like this:

Before (left pic) & After (right pic)
Attached File  Gembone Rough 01 (before).jpg   535.44KB   17 downloadsAttached File  Gembone Rough 01 (after).jpg   472.82KB   28 downloads

Any comprehensive information source or how-to guide for beginners you guys can recommend me to look up?

Thanks in advance.

#2 squalicorax

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Posted 03 June 2013 - 12:03 PM

I was taking to a guy at the gem show who cut and polishes alot of rock material.

 

He starts with a coarse grit sandpaper and works his way down to a 200 grit and then to a 500-600 or the finest possible

 

then it is taken to a buffing wheel. I don't have a buffing wheel my self and am looking into getting one but I dont know where to start. Any wheel for cabachons should work for bone or corals or rocks. 


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#3 mikecable

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Posted 03 June 2013 - 02:54 PM

My Dad did this for years--lapidary hobby--and dinosaur bone was one of his favorites.  It all depends on what you want to accomplish.  You need certain equipment to make cabochons, other equipment to make bookends of desk pen holders, still other equipment to make spheres or marbles.  Here in the US there might be a local Gem and Mineral Club with a clubhouse that has equipment.  I have no idea about Thailand.  

 

A basic cabochon machine is here

 

http://www.diamondpa...m/thegenie.html

 

If you just want a nice specimen for display or to create jewelry my family has known this dealer for more 40 years and three generations.  I used to man their booth at local gem and mineral shows from the age of ten for pocket money.  They specialize in dino bone.

 

http://www.sanjuange...t=0&sort=normal

 

 

The cheapest route, and how my Dad got started, is a simple rock tumbler.



#4 Opisthotriton

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Posted 03 June 2013 - 03:03 PM

You'll probably need a "hard" sandpaper made of silicon carbide rather than the "softer" aluminum oxide. It will also take a LONG time to polish bone by hand with sandpaper.

 

Has anyone tried holding the bone in a table vise and sanding it with a handheld electric sander?



#5 xonenine

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Posted 03 June 2013 - 04:17 PM

the polishing is not too hard to do...

 

Once you have a relatively smooth surface to work with, whether by cutting a slab, cabochon, or grinding a surface to prepare it for sanding/polishing. I like to start with a rough grit like 100 or 200, mostly to make sure there are no saw marks left at all on the piece before sanding. It can be a very frustrating mistake to skip this step, because once you start stepping down to progressively finer grits, any imperfections still visible on the stone/bone will not polish out.

 

Using wet sand paper in the grits I usually go to 200/220, 400, 800, 1000, and 1200 or 1500 for the polish. With each successive grit, you want to create a light slurry, or watery paste. Use the paste to sand, supplementing it with water rinses when it gets too thick, till the grit you are using no longer seems to cut.You can really feel the sandpaper grab and cut with each successive grit if you are doing it properly. It is important to rinse the paper repeatedly so it doesn't load up and become useless. When imperfections are found, it is usually best to just take a deep breathe, and go back through all the grits to rub out the scratch/saw marks.

 

Some porous surfaces are not going to take the kind of shine you are hoping to achieve without some kind of filler or stabilizer...

 

I don't use the dremel for anything except roughing out, with diamond wheels.it is too easy to skip, scratch, and make mistakes during the sanding, it ruins more nice pieces than any tool :). They can be handy for the buffing/polishing though.

 

I have some cut and polished dino bone and corals from the winter, which present a similar polishing challenge, that I will try to get posted soon...

 

Edit: OK, it is hard to do... I should have said, it is not too complicated :)


Edited by xonenine, 03 June 2013 - 04:26 PM.

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#6 donckey

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Posted 03 June 2013 - 06:02 PM

the polishing is not too hard to do...

 

Once you have a relatively smooth surface to work with, whether by cutting a slab, cabochon, or grinding a surface to prepare it for sanding/polishing. I like to start with a rough grit like 100 or 200, mostly to make sure there are no saw marks left at all on the piece before sanding. It can be a very frustrating mistake to skip this step, because once you start stepping down to progressively finer grits, any imperfections still visible on the stone/bone will not polish out.

 

Using wet sand paper in the grits I usually go to 200/220, 400, 800, 1000, and 1200 or 1500 for the polish. With each successive grit, you want to create a light slurry, or watery paste. Use the paste to sand, supplementing it with water rinses when it gets too thick, till the grit you are using no longer seems to cut.You can really feel the sandpaper grab and cut with each successive grit if you are doing it properly. It is important to rinse the paper repeatedly so it doesn't load up and become useless. When imperfections are found, it is usually best to just take a deep breathe, and go back through all the grits to rub out the scratch/saw marks.

 

Some porous surfaces are not going to take the kind of shine you are hoping to achieve without some kind of filler or stabilizer...

 

I don't use the dremel for anything except roughing out, with diamond wheels.it is too easy to skip, scratch, and make mistakes during the sanding, it ruins more nice pieces than any tool :). They can be handy for the buffing/polishing though.

 

I have some cut and polished dino bone and corals from the winter, which present a similar polishing challenge, that I will try to get posted soon...

 

Edit: OK, it is hard to do... I should have said, it is not too complicated :)

 

Xonenine gives an excellent way to polish your bones.

 

I want to add 3 things:

 

1. For a big flat surface use a solid flat piece of glass and use gritpowders instead of (wet) sandpaper. Sandpaper can be used for the smaller pieces 

2. After each grindingfase make sure you clean everything very, very, very thorough

   Even one course grit partical between the finer grits will ruin your work and as said you have to repeat the former steps.

3. To get a real polished look you have to use a polisher after using the finest grit.  

 

Peter 


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#7 AJ Plai

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Posted 16 June 2013 - 11:06 AM

Wow, I haven't checked in a while and there are lots of very useful replies. Many Thx!

Well, I got a hold of some tools that I have been trying out polishing the rough bone slabs I have; here are what they look like:

Attached File  Prep Tools.jpg   583.01KB   4 downloads

This is the tool set I got - nothing big - one of those hand tools that dentist and jewelers use, don't know if something like this is sufficient for the desired result I am looking for though or I may need bigger machine...

Anyway, here is how I have been experimenting with the polishing, don't know if I am doing it correctly or not or if there are more steps or tools or polishing agents that I may need to use. If anyone know, please advice :)

Note: all of the bone slabs I got are probably sanded already but just haven't been polished to bring out the colors intensity and clarity, first I use this:

Attached File  Tripoli & Buff.jpg   585.79KB   3 downloads

I am guessing this is a Tripoli? I used the buff with the applied tripoli and apply it on the rough bone slab first which seem to clean the slabs before proceeding the second step with these:

Just wondering, at this stage do I need to apply hard pressure on the bone slab to get a good result or whether if his usually need to be done several times over and over to get good colors showing? From what I did, the results were no where near the colors intensity of the bone slab when it was wet, so I was wondering if there was something I am missing in this process... Anyway, after the first step I proceed on to this:

Attached File  Rouge & Buff.jpg   518.75KB   3 downloads

Again, I am guessing, this is a Rouge? I applied these and the bone slabs certainly became more shiny and a little darker in hue but again, I saw no significant improvement in colors intensity or clarity.

Do I need something like a vanish, nail polish or other polishing agents to achieve the strong color intensity and that gloss shiny feel that I see in good grade gem bones?

Edited by AJ Plai, 16 June 2013 - 11:07 AM.


#8 AJ Plai

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Posted 16 June 2013 - 11:13 AM

Here are some of the pictures of a bone slab that I tried, so u might know if I am doing something right or wrong:

This was how it started before the Tripoli & Rouge application:
Attached File  DinoBone Various Colors (before).jpg   623.76KB   3 downloads

Note: the picture is actually a different side of the slab than the pic that I applied the polishing agents but the colors feel is pretty much identical.

This is the end result:
Attached File  DinoBone Various Colors (after).jpg   652.92KB   6 downloadsAttached File  DinoBone Various Colors (polished) 02.jpg   695.99KB   6 downloads


But this is the picture of the bone slab when it was wet (this one came from the dealer):
Attached File  DinoBone Various Colors (wet) 01.png   267.58KB   6 downloads

U can see that the colors I achieved wasn't quite like the condition when the slab was wet, don't know if that's actually possible with the tools & agents I am using or I am doing something wrong or the original pic may have been colors-enhanced digitally I have no clue.

Anyhow, thx for any advice and input :)

Edited by AJ Plai, 16 June 2013 - 11:14 AM.


#9 Auspex

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Posted 16 June 2013 - 11:14 AM

The shiny "gem bones" you see are highly polished, using successively finer abrasives. I suppose the effect could be approximated with a clear coating, but the results would probably lack the depth and definition of a lap-polished piece.


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#10 AJ Plai

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Posted 16 June 2013 - 11:15 AM

Or is it already a good job done and I am just being too much of a perfectionist or expecting too much....

#11 Scylla

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Posted 16 June 2013 - 11:17 AM

There are clear coat substances that may bring out more color. But if the stone lacks the color to start with, then you wont get it to show. I think that this is not likely to become a museum piece but a reversible method would be nice. If the stone is a bit porous, then all the polishing in the world will not get that "wet" look and a clear coat is needed.



#12 xonenine

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Posted 16 June 2013 - 11:22 AM

what I have seen is that a clear sealer or resin is often pored on the bone/piece to be polished, simulating the high polish of a well agatized piece.

 

This substitute doesn't really meet the goal of a polish with successive grits, it often is the only way to keep a high gloss on more porous pieces.

 

I wouldn't use the rouge, or tinted polishing compounds myself, as they darken and give an unnatural tint to the pieces.

 

As far as the Tripoli, I am uncertain what grit you are working with, or if it comes in a variety of grits.


"Your serpent of Egypt is bred now of your mud by the operation of your sun; so is your crocodile." Lepidus


#13 xonenine

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Posted 16 June 2013 - 12:16 PM

here is a piece of bone that came "dome polished" from a seller, about 1 1/2 lbs. I cut a first slice from it in order to see what a natural sanding would produce.

 

what doesn't show well, in original picture, (I should have used the tripod along w the lights) is how thick and unsatisfactory the original sealer coating was. It is waxy, and has an unattractive "orange peel" texture, with pits where the resin sank unevenly, from pouring one thick coat, instead of several.

 

the wet1, wet2 are photos of the cut rough, unpolished side.It is a very dull stone as can be seen, pre polishing. This evening I will sand it with successive wet sand grits, and post the results :)

Attached Files


Edited by xonenine, 16 June 2013 - 05:17 PM.

"Your serpent of Egypt is bred now of your mud by the operation of your sun; so is your crocodile." Lepidus


#14 xonenine

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Posted 16 June 2013 - 12:41 PM

another reason I opt for hand sanding, (short of a lapping machine) is that a lot of these minerals, wood, fossils bone, etc have alternating areas of soft and hard materials, and the rotary tools are just too aggressive for the combination of hardness, they create furrows, or more work taking out inadvertent gouges and scratches produced by the tools... :)


"Your serpent of Egypt is bred now of your mud by the operation of your sun; so is your crocodile." Lepidus


#15 donckey

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Posted 16 June 2013 - 05:07 PM

Hi Plai,

 

In the Netherlands we use the word "slijpen" for sanding/grinding. In the dictionary it is translated in grinding or polishing.

Polishing however is no grinding. Polishing of stones means a finishing tough of a very smooth surface which will get a shining look.

 

It is important to have a really smooth surface before you start polishing. I would use atleast grine >1500. What was the finest grine you used?

 

For polishing I would advise you to use felt or soft (cow) leather. You can buy these items also for the tool you bought. 

It is also important to use the right polish agency for the bonematerial you want to polish.

Some examples of polishing agencies are: Chromium oxide, aluminum oxide, tin oxide and cerium oxide.

 

I mostly use cerium oxide with a soft (cow)leather piece of material. You have to experiment a little with rotation speed and applied pressure.

It does not take long to get a nice glow so you will see quickly if your method is succesful.

 

Peter


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#16 xonenine

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Posted 16 June 2013 - 06:03 PM

the rough piece, I quickly removed some of the worst saw marks, then 320, 400, 800, and 1000 grit. I think it shows the depth of color very well now, and a lot of detail. It will be good stock to cab some more. It seemed unenhanced when cut, though I imagine heat could alter the coloration easily as well as dyes.I expected it to come much duller and fade when dry, but this is very dense, I have another piece a few lbs. that has a purple hue I will have to dig out now. :)

 

btw, this doesn't really get much darker now even wet, but is more a matter at this point of my selecting to grind it down to expose the best cell walls that are pleasing to the eye, and a better overall sanding several times with the roughest grits I use, before really doing a good grinding.

 

And like Peter says, now one would choose to polish it, or stabilize it and polish, to get that wet look.I usually just use a little beeswax on my pieces, and don't do a lot of polishing with compounds.

Attached Files


Edited by xonenine, 16 June 2013 - 07:56 PM.

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"Your serpent of Egypt is bred now of your mud by the operation of your sun; so is your crocodile." Lepidus


#17 AJ Plai

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Posted 18 June 2013 - 01:46 PM

what I have seen is that a clear sealer or resin is often pored on the bone/piece to be polished, simulating the high polish of a well agatized piece.
 
This substitute doesn't really meet the goal of a polish with successive grits, it often is the only way to keep a high gloss on more porous pieces.
 
I wouldn't use the rouge, or tinted polishing compounds myself, as they darken and give an unnatural tint to the pieces.
 
As far as the Tripoli, I am uncertain what grit you are working with, or if it comes in a variety of grits.


A grit, I assume, is the tool you use to sand down the surface of a specimen to achieve the flat smoothness? If that's the case, I haven't been using that at all, just the hand tool with the mini buff wheels like the shown in the pics. It seems to me that the bone slabs came pretty much flattened and fairly smooth already so I didn't try to find ways or tools to sand them down any further; just went straight to the polishing with the tripoli and the rouge. Though I admit, I really don't have much clue whether if I am doing it correctly or not, heck truth be told, I am not even sure if I understand what the tools and agents I am using are really called! I pretty much just follow the instructions given by the previous owner of the tool set I have (she used them for polishing minerals & gemstones). It's kinda like my experimental attempts just to sate my curiosity about agatized bones polishing.


I have heard that u can use art vanish or nail vanish to coat the slab's surface to get a shiny look on the bone slabs which can help to increase colors intensity by a little - is this actually ok? Or should I stay away from it?

Thx again for all the replies and advice. :)

Edited by AJ Plai, 18 June 2013 - 01:47 PM.


#18 Auspex

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Posted 18 June 2013 - 03:32 PM

"Grit" refers to the coarseness or fineness (usually of sandpaper): the higher the number, the finer.


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