Part Two - Beginners Guide to Grinding, Sanding and Polishing Gemstone Cabochons

Oct. 21, 2008 - PRLog -- Part two of two parts.

To view part one:
http://www.prlog.org/10131086-part-one-beginners-guide-to-grinding-sanding-and-polishing-gemstone-cabochons.html

To view this with images and videos:
http://gemstone.smfforfree4.com/index.php/topic,483.msg1663.html#msg1663

To view examples of finished gemstones that are used in gemstone jewelry designs:
http://taogem.com/taogemst_myzencart/

Work your stone nice and easy......

View video one  for a short glimpse of the Agate on a 220 grit
View the second video for a glimpse of the Jasper on a 400 grit.

Here is as good a couple of pics of the surfaces for both the agate after being sanded on the 220 and the Jasper off the 400.

You can already feel the difference with your fingers not to mention see the difference as well. It is a dramatic difference. Make it a habit prior to moving on to your next finer paper to inspect closely for any scratches that stand out. Scratches that are obvious and stand out over the course surface as a whole. The surface of the cab should be consistent. If you see a scratch that stands out, continue with the grit you just finished with until you have achieved a surface without any irregular scratches.

Move on the your next finer grits. I moved on to a 400 for the Agate and and a 600 for the Jasper.

A video if you would like to see a glimpse.

Here are the surfaces once the Agate was removed from the 400 and the Jasper off the 600. Again, look closely for abnormal scratches, and any pitting that may show themselves.

You can if you like, take the Agate to the next finer 600 grit paper if you like. I did not find it necessary. But this was just me. Everyone sorta works a mineral a little differently I think. Lots of variables.

I found that the 400 was fine and I was pleased with the surface of the Jasper after it's round with the 600.

Now I want to do a real fine paper combined with some tin oxide paste. You can use this step like I am showing on a circular wheel or you can do the same with a flat disc that we talked about earlier included with most combination cabbing machines.

This video gives a glimpse of me using a somewhat worn 600 grit paper with the oxide paste. I took the Agate and Jasper through this step. The final sanding step to polishing.

I spent quite a bit of time on this step. More so with the Agate than the Jasper. Again, only because the Agate is softer.

Here are the two stones after some time on this step. The Agate is a bit easier to see the changes in. Only because of the quality of the pictures. Hard to show like I would like to have been able too.

Now we are ready to hit the polishing pad. I have talked before about the use of building up friction while polishing in order to create heat so as to sorta melt the oxides into the stone. This can result in a great shine.

For this tutorial, I would like to have you disregard that theory, and consider working with it as you become more comfortable with the polishing process. There are considerations like cracking of your cab due to the heat.

Continuing with the basics, we will treat the oxide polish just like any other abrasive step.

Take a look at this video clip. It shows the application of the oxide paste to a leather pad. Once I applied the paste as shown in the clip, I leave the wheel running long enough to dry out the paste on the leather polishing pad.

What this does is turn the polishing step into more of an abrasive step. It is dry not wet. Polishing with your oxide as a wet paste on the pad has it's place too. For this short guide, I am using it dry.

What I am going to do is continue on through the final phase, the polishing phase, but I am using the paste in the same way as I did any other step prior. Letting the abrasive polish in this case in accordance to it's own grit. Not pressing hard. Letting the oxide polish as it will naturally in accordance to the oxides grit ability. Nice and easy......

Here is a short video clip showing this step[/color][/url]. Nice an easy.. Gradually pressing just a little more. Not a lot. Pressing just a little more, but not enough to let the stone develop any heat.

Another short video showing the same.

For what it's worth, these two clips give the impression that the polishing pad is moving sort of slow. In fact it is moving rather fast. I find better results with a faster moving pad than a slow one. I don't know why the video gives the impression it moves so slow, but I would guess that in fact it moves about twice as fast as it appears in the clips.

Finally, we can see a pretty nice finish on the two cabs we started with. Neither of these have been beveled or had the edges rounded. This short tutorial was just to show basic grinding, sanding and polishing.

The truth is that there are variations of these steps. You can find yourself using a worn 400 grit belt instead of a new 600 grit belt as an example. There are many variations, but the end result and the basic process is the same. That is to work through a series of different abrasives that will bring your cabochon to a desired state that you believe will allow you to move from sanding to polishing. Remember too that it is not uncommon to realize that you have to repeat a step. This is discovered as you spend more time sanding. It is a learning process. Just keep at it and have fun  :)

If you have tutorials related in any way to lapidary work. Either with gemstones or jewelry, please post them. It does not matter if either myself or another member has posted a similar guide. We can all benefit by learning how similar processes/techniques work differently and successfully for each of us.

We are gaining new members who are looking for resources on how to learn different lapidary related niches. Interests in both jewelry design as well as working with gemstones. If you have a little something in the form of a guide or tutorial, we would love to see them.

On the other side of the coin. If you would like to see something specific in the form of a tutorial or guide, please feel free to request it from where ever you like on the forum. Or PM me and I will make a general announcement for your request.

Hope ya liked this one!

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