smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 13, 2022 21:59:16 GMT -5
Hello!
I’ve been cabbing for a few months now with my Kingsley North Cabber 8. I’ve been making some cabs I’m satisfied with but I can never get the backs completely scratch free on the larger cabs. So, after reading your cabbing PDF and the section on polishing the backs, I’ve decided to get a flat lap for the backs of the cabs.
Now I’m curious… when to switch between the Cabber and the Flat lap?
Should I do the domes and sides all the way on the Cabber and then finish the backs with the flat lap? I’ve been using my hands but dopping seems necessary as I could see the cab shooting out of my hands while trying to hold the dome.
Or should I use the Cabber all the way to the 600 wheel, move to the flat lap and finish the back and then return to the Cabber to finish the dome/sides?
I’ll probably work out some method through trial and error but would really appreciate any tips or thoughts on this.
Thanks
SQ
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Post by stardiamond on Apr 13, 2022 22:32:27 GMT -5
How large is large? What are you dopping with? I don't polish backs unless there is a very good reason. I occasionally make flat top cabs which is the same as a polished bottom. It is easier to get scratches out when there is a dome. When I do a flat top, I use a figure 8 motion and then rub a pencil over the face to make sure the scratches are gone before moving to a finer grit. Each grit has a job to do so complete the job before moving on. Softer material is more forgiving than hard material.
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 13, 2022 22:54:29 GMT -5
How large is large? What are you dopping with? I don't polish backs unless there is a very good reason. I occasionally make flat top cabs which is the same as a polished bottom. It is easier to get scratches out when there is a dome. When I do a flat top, I use a figure 8 motion and then rub a pencil over the face to make sure the scratches are gone before moving to a finer grit. Each grit has a job to do so complete the job before moving on. Softer material is more forgiving than hard material. Large is over 1.5” in diameter. My wheels are 2” wide and I don’t get much movement when doing the backs. It would be quite a small figure 8 movement. Note sure if going over the edges of the wheels is an issue… I’m not dopping yet but would consider it for doing backs on a flat lap if that makes it easier. I’m only cabbing for myself at the moment and really like an all over polish to enjoy looking at the stone from all sides. Thank you for the advice and tip about using a pencil! |
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Post by stardiamond on Apr 14, 2022 0:03:21 GMT -5
I have worked with and without a dop. Without is harder on my fingers. I dop with superglue so I have to go without a dop when working on backs. I think it can be done when using wax. Wax and I don't get along well. I tend to use shapes that are about an inch in width, so holding the cab vertically, I have room with a 1 1/2 inch wheel. Going over the edges is ok as long as they don't dig in.
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Post by rmf on Apr 14, 2022 3:37:22 GMT -5
As stardiamond said. I do not polish the back unless it will add to the stones beauty (rutilated quartz, glass, opal...). I polish my cab the put a chamfer on the bottom to reduce chipping while setting. when I put the chamfer on I grind the back a little with a 280 wheel. Sometimes there are saw marks and I try to remove or reduce them depending on the stone, I have also cut double cabs where you dome both sides and then you have to top both sides. If you are wanting a truly flat back then a small lap is the way to go. I don't think it is necessary for most opaque stones like agates and jaspers. If I did use a lap to flatten the back of the cab I still would only go down to about 280-325 unless there was a reason for a polish. Typically the polished back on things like rutilated quartz only get a semi polish to 1200 or 3000. just enough to let the light do it's best for the stone. The back does not need what the top gets. |
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Post by liveoak on Apr 14, 2022 6:37:31 GMT -5
First I'll say that I'm pretty new to cabbing and I'm sure others will weigh in that know much more than I do. But, I'm also in the camp of wanting my backs polished, if the wearer is going to see the back of the cab.
If I'm setting it in a closed bezel then of course, not necessary.
I had the same question about grits, laps, etc & what I came to (and still experimenting with)
was to completely use a flat lap (actually I'm using the end lap on my KN cabber6 ),
BUT what I found at least with the last couple of stones was not to start too coarse, unless the back has bad saw marks. And I always dop with wax for both sides.
I got pretty good results on a recent piece, by first grinding the back on the hard lap my cabber came with ( 360) and then progress through all the grits on a resin lap (I'm using Super Nova discs from Johnson Brothers)
325, 600, 1200, 3000, 8000. I then even used some cerium oxide on it & it looks pretty good.
For a change no scratches.
That's whats working for me.
Patty
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rixrocks
having dreams about rocks
Member since September 2019
Posts: 51
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Post by rixrocks on Apr 14, 2022 9:58:33 GMT -5
I dop the stone with super glue and dome the cab on a cabbing machine. If I want to polish the back once I'm done shaping and polishing the face, I do it on the flat lap after removing the dop stick. It's easy for the cab to fly out of your hand once you put it to the flat lap and you can ruin a beautiful cab. So I start the flat lap out at the slowest speed so it doesn't jerk it out of my hand. Once it gets started, it's easy to increase it to the desired speed. I have few ever slip by using this method.
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Post by hummingbirdstones on Apr 14, 2022 10:02:18 GMT -5
I always use a flat lap for the back of my stones. I just can't get the backs flat on wheels. Plenty of people can, but I'm not one of them.
My personal routine is to complete the front of the cab completely through polish, and then move on to the flat lap to do the back. I dop my stones on both sides only because it's easier on my arthritic fingers. My advice is to dop the stone (I use wax) to do the back on the flat lap. It is really difficult to hold onto them on a flat lap and they go flying if you lose your hold on them.
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Post by stardiamond on Apr 14, 2022 11:09:19 GMT -5
I frequently find myself working on heels. When the rough side shows a nice pattern, I just dome it. When the bottom shows a better pattern, I need to make the rough side the bottom. I mark a grind to line and then start with an 80 grit wheel to remove most of the material and then use an 80 grit end lap to get it perfectly flat. I have no problem sanding scratches off the back with a wheel since I am starting with a flat surface.
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 14, 2022 21:58:19 GMT -5
Thanks for all the replies. It’s giving me a bunch to think about. I appreciate the insights into your techniques!
Im going to do my best to get the backs done with my wheels and you’ve given me some great advice. If I’m still having trouble, I’ll definitely try doing a few with a flat lap, with and without dopping… which is its own big bag of noobie questions.
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stefan
Cave Dweller 
Member since January 2005
Posts: 14,113
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Post by stefan on Apr 17, 2022 11:04:17 GMT -5
If I'm not mistaken you can add a flat lap to the end of your cabber. I thought the Kingsley's came with a 360 grit flat lap?
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Post by Rockoonz on Apr 17, 2022 14:17:50 GMT -5
When lapping things that are slippery I get the lap wet, place the stone on the stopped lap with the best grip I can, then start it. If it feels like it's getting away I stop the lap, also when I want to stop and look at my progress. I don't think I've ever lost one since I learned that method.
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 21, 2022 12:40:33 GMT -5
If I'm not mistaken you can add a flat lap to the end of your cabber. I thought the Kingsley's came with a 360 grit flat lap? Yes, it has a 360 flat lap. I'd really like a range of grits tho. Also, I'm finding the vertical lap harder to use than a horizontal lap, which I use a lot at work. I actually just got the Ameritool 8" Universal Grinder. Only had it a week but I really enjoy being able to use it on the kitchen table. This weekend I'll try using both the flat lap and cabber to try getting a cabochon the best I possibly can. |
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Apr 23, 2022 9:31:35 GMT -5
Got it. THey sell a decent range of grits for cabbers on Amazon. Prices fluctuate wildly so be careful ( I mean like one day and 80 grit metal flat lap will be 19.99 then the next day it will be $40!) I got a bunch of 4 inch diamond disks for free recently and am in the process of mounting them up for my 6 inch cabber
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 29, 2022 11:55:10 GMT -5
Thanks again for the replies. I’ve been practicing with my new flatlap and am loving it. It’s really quiet and easy to clean compared to my cabbing machine. Still trying to figure out the grit sequence tho.
If a back is scratch/saw mark free, just a little cloudy, what grit do you start on? Patty mentioned starting on a 360 hard wheel before going back to a 325 soft wheel and progressing through the series.
I experimented dopping with 5 minute epoxy but came to the conclusion that it needs to set overnight… worked ok with the smaller stones after 6 hours. The epoxy seemed to soak up the water a bit. May have to protect it with a lil clear nail polish, which I think I’ve read about on here.
Anyways… when flat lapping a surface with no apparent scratches, where do you start the polish?
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on Apr 29, 2022 13:30:22 GMT -5
Did a google search and found more info on this forum.
Seems a slab saw can leave 100 grit scratch marks that can be “invisible” or hard to see until later grits. This leads some to start on a 100 or 120 disc to remove the scratches and have with a uniformly ground surface. Seems the slab saw scratches can take a while to get out too
I practiced starting on the back of a small blue tiger eye, that appeared scratch free, on the 220 hard disc and noticed small scratches after the 600 disc. Also I think too much material was removed as the cab is a bit thinner. Had to redo the chamfer as well.
Also had a crazy lace that seemed scratch free so I started the back on a 360 hard disc and then noticed small scratches only at a particular area of the banding patterns in the agate. This area won’t polish up even though the surround areas look great.
Just trying to experiment and troubleshoot. Thanks. Any thoughts or advice would be appreciated.
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Apr 30, 2022 17:52:00 GMT -5
If you have saw marks your going to want to use 80 or 100 grit. It will take a bit to remove them (as you have to remove the material down to the saw marks.
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Post by jasoninsd on Apr 30, 2022 18:30:39 GMT -5
smokeyquartz - Deciding which grit to start working the backs of cabs is completely dictated by the hardness of the material. The Crazy Lace you mentioned, I'd probably start with my 80 grit disk...but I've worked some material that was so soft that my 1200 wheel was removing material, not just scratches (technically, all grits remove "material"...I just mean the 1200 removes soft material like an 80 removes hard material...). Like with your Tiger Eye, I might start out on the 220 hard disk, but use light pressure...
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smokeyquartz
off to a rocking start
Member since April 2022
Posts: 9
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Post by smokeyquartz on May 1, 2022 14:36:07 GMT -5
Thanks for the advice! This is just the type of thing I was wanting to know.
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