Using Sintered Diamond Burs
Hi and thanks for getting some sintered diamond bits from me.
I thought I should write up a quick user guide for them to give you an idea of how to use them to full effect. Note this will be mainly in terms of their use in opal carving. For a video demonstration feel free to check out any of my carving videos on the YouTube channel “Roys Rocks”. Remember to always use water and don’t be too scared about getting cut by the burrs they are quite safe on skin especially with water.
This kit comes with 10 pieces but this does not mean you need to use them all every time. Some of the burrs are the same coarseness/grit and you can identify this by the colour coding band on the shaft.
The order is (ANSI minimum grit): Black (80), Green (90-100), Blue (120), Red (240) and Yellow (600).
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I hope this very brief guide helps but if not, there are many videos on my channel using these exact burrs so check it out and ask me any questions you have.
Thanks and have fun carving,
Roy (YouTube: Roys Rock)
Stay Safe
I recommend at minimum safety glasses, lubricating with water and wearing a P2/N95 grade mask even when cutting wet. Vision and breathing are quite useful for us humans so look after your eyes and lungs. Also, for carving I always recommend using a flex shaft attachment on your rotary tool as water and electricity do not mix and you don’t want to give yourself a zap.
When Carving
I use the blacks to remove excess material/thick crust but you have to be careful not to go too far. Pull up as soon as you start to see the colour bar in the opal and switch to a lower grit. I typically jump straight to red or if you have gone too far yellow. Green and blue are great alternatives to the blacks when you get thinner crusts, in which case, start with one of those then go for red and/or yellow.
Once up to the yellow burr you should be just about finished shaping the piece and you will get a light frosted effect over the surface when dry. There should not be any large chips or deep scratches from earlier diamond burrs as they will take longer to get rid of in the polishing steps.
The full polishing process involves then moving to a resin burr and is explained fairly deeply in this video “How to Cut/Carve/Polish Opal Efficiently (Diamond Pacific Nova Points)” (https://youtu.be/l2-ihVH1ItE).
Maintenance
When you are done using them give them a dunk in water and wipe. It is not a highly important step but at least drying the burr after usage can avoid any chance of rust.
If the outer diamonds stop cutting well the burr may need “dressing”. This may be required after many years of cutting opal as it is such a soft stone but may happen if used on harder materials at a fast rate. “Dressing” is just a way to reveal more diamonds and/or sharpen the ones on the outside. There will be a video on this on the YouTube channel in the future (once I have finally blunted one). It involves using a piece of compressed metal oxide (such as tin oxide) to peel back the outer metal surface and is commonly done for these types of bits and saws (especially if sawing large slabs often).