Using the Ceramic Lap

by Art Kavan, Old Pueblo Lapidary Club

Using the ceramic can be very frustrating and at times even with a lot of experience it can be difficult and bring a little humility back into your life. When you get it working there is nothing like it. I use a Facetron, if you use a ultra tech. or something else they all have there little idiosyncrasies. For instance I use a lot of pressure on stones above six MM, if using an ultra tech, that much pressure would snap the stone off the dop if you are using the little lever above the stone, so UT users should keep your fingers on the stone and not on the lever.

Here is the equipment list to use this procedure. One ceramic lap, I use a falcon 8″. Depending on how excellent a polish you want, one 2 oz bottle Crystalite 100,000 diamond spray, and one two oz bottle Italdo 200,000 diamond spray. One Norbide stick by Norton. One tube of either Super Lube by Permatex (Loctite) or a tube of Lube Gel from Radio Shack catalog number 64-2326, they are both made by the same company in NY. One safety razor blade, one box of Kleenex and I use bounty paper towels. One 2oz bottle of alcohol.

I use the Crystalite just as it comes out of the spray bottle, the Italdo I take an empty 2 oz bottle and pour half the Italdo in and then fill both up with alcohol, for some reason known only to the polishing gods Italdo straight out of the bottle causes problems. I get an excellent polish with just the 100,000 but for competition the follow up with 200,000 really finishes it off.

To proceed you get everything out and set things up, if it is a brand new ceramic I recommend that you break it in using this procedure. You will always charge the lap using the same technique, I fold up a Kleenex until it is about two inches square and lay it right in front of me, tear a sheet of paper towel in four pieces and spray one with water, you want it damp not ringing wet to wipe off the facet for inspection.

Now take your lube and put a dab about the size of a BB on the tip of your finger, I put little dots from the hub out to the rim usually five rows about six dots in a row very little dots, now take your razor blade and on the slowest seed about 50 rpm spread the lube out holding the razor blade on the lap for about ten or fifteen seconds, open your folded Kleenex one fold and wipe your razor blade clean. Now take your diamond spray about eight to ten inches above the lap and give it one quick burst directly pointed at the lap. Pick up your folded Kleenex and while the lap is still turning use a finger under the Kleenex and wipe the lap off going back and forth to the hub and back to the rim four or five times.

If you are breaking in a new lap you would use the Norbide stick and with very firm pressure work it back and forth, I won’t kid anybody it takes a long time to break a new lap in approx.. four hours so you won’t do it all at once. I recommend working twenty or thirty minutes and then switching to polishing a lab corundum and coming back to the Norbide again. You should have very little trouble with corundum and it is the easiest material to polish on the ceramic.

OK you have it broke in and you now know the procedure for charging it. The biggest problem for all is too much diamond, ninety percent of the time it is too much diamond. When you are having scratching problems here are some things that should help you out. Try taking your Norbide stick and working it back and forth like you did when breaking in the lap, many times this will work out the contamination. Try recharging as a lot of time you will get to much swarf on the lap and this will cause scratching.

For non competition stones of ten MM I can polish one row of facets before recharging, if competition polishing half or sometime less than that. After awhile with experience you will develop a sense for just before it starts scratching. I keep a 2oz bottle of alcohol there also to recharge. I spray the lap down vigorously with the alcohol while the lap is turning and wipe it with the same tissue, throw the tissue and damp paper towel in the waste can and charge as before. If your lap is contaminated you need to scrub it down using this procedure, also going from 100,000 to 200,000 I do this, take the lap to the sink and wet it put some Bon Ami or other scouring powder on and scrub it with a plastic or non scratching pad, both sides, rinse it very good and scrub it again using dish soap, rinse well, dry it off and its ready to use.

I use a speed of fifty to one hundred never faster, on very fine facets I will shut the machine off and just work the quill back and forth by hand to put the meet in. Coming off a pre polish of 1200 the polish should come up very fast like I will sweep four times from the rim up to the hub wipe off and inspect the facet by the third series if you don’t have a good polish you are doing something wrong, you should also be able to move the facet around quite easily, by this I mean working the meet points.

You do have to be aware of heat build up, it is less using the lube but if you sweep more than four times the stone can get hot and shift, even in epoxy. If I am in a hurry I will use the wet inspection towel to help keep the stone cool. If you use diamond bort on copper or for any other reason in your shop it can be a very difficult problem when it comes to using a ceramic, I had many problems polishing from contamination caused by bort, I never use it anymore and I have very little problems.

One trick I picked up recently with polish is that I was having great difficulty polishing the table on a topaz, normally I spend maybe a half hour at the very most on any table, this one I was in my second day and running out of every thought I could try. I took a old tin lead that I never used diamond on before and charged it using the above method with 200,000 diamond and in less than five minutes the table polished out perfectly. The solution is always there it just takes time to find it.

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