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Author Topic: Scuff polishing stone with 8,000 and 14,000 NOVA wheels  (Read 1416 times)

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Redrummd

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Scuff polishing stone with 8,000 and 14,000 NOVA wheels
« on: November 24, 2016, 10:16:21 AM »

I have been cutting and polishing stone for over 50 years now and over the decades I have developed some unique methods to do just about every aspect of cutting and polishing stone.  As I write comments about a known but rarely used method I have decided to try and clearly describe how it is done and to "sticky" it for others to use and perhaps pass on.  Thus the recent threads I have added to this section.

If you are already going to a well worn NOVA wheel 1200 grit polish or a NOVA 3,000 grit polish, you are at the 1st polish stage so just get an 8,000 and 14,000 NOVA wheel for the final polish.  I cut commercially and use 3,000, 8,000 and 14,000 NOVA wheels for 90%+ of my final polishing but for most people only doing the 8,000 and 14,000 are fine.  I occasionally go to my ZAM setup for a final light "dusting" with ZAM  if the 14,000 diamond isn't giving a mirror polish and on some stone, usually Jade, I go to the Fabulstre and then ZAM.  ZAM is a polish while Fabulstre has some grit in it.

I do a test polish on EVERY stone I use to determine the best "mix" to get the best polish.  Occasionally I find a stone will "cloud" a bit when going to a 14,000 polish and I drop back to 1200 grit sanding and re-polish to the grit the best polish was observed.  This is usually discovered in the test polish stage and with some stone, usually a Jade, the best polish is as far down as a worn 1,200 grit or a 3,000 grit NOVA wheel.

Again for at least 70% of the stone I polish including most Jades and agates - I use "scuff" polishing which is polishing on the 8,000 and 14,000 wheels nearly dry.  I do this with very light pressure especially on stones other than Jade which I polish dry on NOVA wheels at times.

The real trick for "scuff" polishing is getting a VERY nearly dry wheel for the final polish and to develop a feel for the correct drag.  The very slightly damp wheel keeps the stone from hydroplaning on the polishing wheels.  I put a cloth bandaid (BANDAID brand 1 inch FLEXIBLE FABFIC) on the end of both index fingers and keep a bowl of water next to the wheels.  I get the bandaids wet and let them slightly drag on the 8,000 and 14,000 wheels as I am doing the final polish stages.  As the bandaids start to get dryer I use less pressure and faster movement of the stone turning it 90 degrees as fast as I can and then turning it a full 180 degrees every few seconds.  This will get you a mirror polish.

If you drop the stone wash it off in the bowl of water as the drag used to scuff polish will often pull the stone from you.  As you are using very light pressure the stones do not break as they fall rather than get slammed by the wheel grabbing them.  If they are getting "grabbed" and thrown you are using too much pressure, allowing the wheel to get dry, or moving the stone too slowly.

Now, initially you will ruin some stones as you will burn them or get steam blow outs from too much heat caused by too much pressure or too slow in turning.  The stone should never get any warmer than slightly warm if touched to your cheek although Jade can be allowed to get hot but not too hot to be held against your cheek.  You must use the damp bandaids to get this to work.  In fact I have determined that the best bandaids are (BANDAID brand 1 inch FLEXIBLE FABFIC).

I first discovered this when polishing Jade and later found it works on most stone.  There are some stones that it MUST not be used on: 

Copper based stones such as Chrysocolla, Malachite, Shattuckite, Azurite and Gem Silica

Opal

Turquoise

Variscite

NOTES -

1) 1,200 grit NOVA wheels are the most used wheels in my work.  I use newer ones to wet sand and nearly worn out ones for final sanding wet and first stage "scuff" polishing.  I do this sometimes with one side getting a drip to be wet sanding and the other side pretty much dry to start the "scuff" polish.  In fact I have a problem keeping the worn wheels as I totally wear them out.  When I get short on the worn 1,200 grit wheels I use 3,000 grit NOVA wheels for the start of the "scuff" polish.

2) Scuff polishing practices only work with broken in 1,200, 3,000, 8,000 and 14,000 grit wheels.   It takes about an hour or two of wet polishing to get a wheel properly broken in.  Wheels that are not broken in will quickly shred the bandaids so you will know when they are ready for scuff polishing.  You can hasten the break in by dressing the wheels with a CLEAN aluminum oxide dressing stick to take off the worst of the "texture bumps" a new wheel has.

* Eastwind Diamond sells a flat lap they refer to as "Diamond Dot Disks".  These have a magnetic backing.  These disks can be safely used to "grind" most Jade without causing harmonic vibration issues.   

* Often I use spit for the very last scuff polishing on Jade!  That is kind of my "secret" stage to Jade polishing....
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Redrummd

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Re: Scuff polishing stone with 8,000 and 14,000 NOVA wheels
« Reply #1 on: November 24, 2016, 10:17:08 AM »

This post is to reserve the space for additional information or photos later.

BAC

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Re: Scuff polishing stone with 8,000 and 14,000 NOVA wheels
« Reply #2 on: February 11, 2019, 02:51:11 PM »

Dear Redrummd,   

A big THANK YOU for this post!... Just got a 'brand new' 35+ year old Raytech "Gl-I Polisher". It has literally never been used, just sitting on the shelf in a jewelry store for decades. Works great and I am VERY ANXIOUS to try your 'scuff' polishing approach. I imagine that is exactly what this machine was designed to do!

Cheers,
-Barry
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