Amost 2 years ago I reviewed the Greenway polishing lap. It was the ultimate Emerald polishing lap in my opinion and I have been enjoying the experience ever since. Then I received a pre-production sample of Jon’s latest brainchild which has turned out to be a considerable improved version over the original Greenway.
With this new design the Greenway chrome oxide polishing section is inlaid into the centre of a sintered diamond pre-polishing lap. The sintered part is a ceramic material formulated to function with water as the lubricant.
There is nothing new about a dual lap, I have a steel/tin lap which I’ve had since the ’70′s. Most dual laps use loose diamond grit on a metal lap for the pre-polish carrier and the lubricant of choice is oil. For most gem material this is not a problem but if the stone has surface reaching inclusions and flaws the black cutting swarf can be forced into the stone with very difficult to remove staining.
Unfortunately simply using water instead of oil doesn’t fix this problem. A gem of questionable integrity does not behave predictably and low quality Emeralds tend to tear and pull out more readily when water is used on a metal pre-polishing lap.
The original Greenway will produce a fine polish, even from a 1200 lap, with reasonable expedience, especially if the stone is of modest size. Unfortunately it isn’t instant and facet edges will tend to suffer, not much of a problem except that crack and inclusion edges suffer in a similar manner, making them more obvious than they need to be.
The secret to a perfect polish is a perfect pre-polish and for even the most horrible examples of Emerald sponge I have tried so far, this new lap makes it trivial. It is important to admit that I am a restoration cutter to the jewellery trade and have little or no say in the type or quality of stone that I am called to work on.
Although this lap seems to have been made specifically to address my problems it also has received rave reviews from testers on a variety of other material. There was some discussion about the aggressiveness of the pre-polishing ring and I believe Jon is contemplating having two versions. I have been testing the light version.
I have had no trouble getting a fine pre-polish from 600 grit almost instantly but the facet is reluctant to move unless I add speed. I have been more careful pointing up my facets with the 600 lap to avoid wasting time. I understand the more aggressive version will easily move facets but as I cut a lot of small stones it may not be such a good idea for me.
A top quality polish, quickly and easily achieved with almost no learning curve makes this lap a winner but its real joy is when you are using it. With just a light water spray a couple of swipes, clean the facet and on to the innercircle for a couple of more swipes….done. I have resisted making a full sweep from the outer ring to the polish without wiping the facet because I can’t bring myself to do it. Other testers have not been so reluctant and have not reported any contamination. In theory any diamond removed from the outer ring will simply wash away.
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