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Post by liveoak on Mar 16, 2022 9:24:27 GMT -5
I'm looking for input on how people polish the backs of cabs (when needed). I've seemed to have less than good luck lately with my hard diamond top plates on my flat lap.
Lots of scratches that don't come out.
Is it better to use a resin bonded disc ? Like Ameritool or Super Nova's ?? Is so with foam ? so more versatile ?
Appreciate any advice before I spend more $ I might not need to 
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Post by opalpyrexia on Mar 16, 2022 10:59:24 GMT -5
If I have a finished cab that still has some saw marks on the back (that I missed in my hurry to start cabbing), I take those out with a broken in/used 600 grit disk on my flat lap. Occasionally I have to first resort to a well-used/old 260 grit disk. From the 600 disk it's on to the 600 —> 1200 —> 3000 wheels on my Genie.
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Post by liveoak on Mar 16, 2022 11:16:22 GMT -5
Interesting.
I wouldn't think you could technically keep the cab flat by using the wheels,
but then I guess it's only for polishing,so probably fine.
Thanks for the input (and saving me $).
Patty
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Post by opalpyrexia on Mar 16, 2022 11:42:28 GMT -5
Interesting. I wouldn't think you could technically keep the cab flat by using the wheels, but then I guess it's only for polishing,so probably fine. Thanks for the input (and saving me $). Patty
When on a given wheel I'm rotating the cab's orientation every 5-10 seconds. I also change the area that touches the wheel by pressing one end (or point) down and then the other(s). It just needs to not stay in one position too long.
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Post by liveoak on Mar 16, 2022 12:25:58 GMT -5
You're confirming what my husband always says, "It's all in the wrist".
I'm TRYING to get that !
I think when I used my hard diamond wheels I obviously started with too coarse of a grit.
Will have to experiment more.
I was wanting to add anther flat disc on my end arbor of my cabber- so maybe a 600 is a place to start.
Thank for your help,
Patty
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Post by stardiamond on Mar 16, 2022 12:38:16 GMT -5
Polishing the back is the same as polishing the front with two exceptions:
1. It will probably need to be done without a dop and can be hard on the fingers.
2. It is easier to hit the scratches on a domed cab than a flat side.
Doing a figure 8 against the wheel will keep the bottom flat with the possible exception of the 80 grit. I frequently flip cabs making the domed/uneven side the bottom. I remove most of the material to make it flat using an 80 grit wheel than complete the process using an 80 grit end lap.
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Post by liveoak on Mar 16, 2022 13:02:31 GMT -5
I have tried dopping the front to polish the back- with mixed results- works as long as I don't have to get the razor blade to scrape off the wax on the front. But a short dob stick seems to work.
When I try using just my fingers some times the flat lap grabs it out of my fingers & of course, it scratches the front.
Much much more experimenting needed - appreciate to hear what works for others.
Patty
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rockbrain
Cave Dweller 
Member since January 2022
Posts: 3,179
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Post by rockbrain on Mar 16, 2022 14:47:46 GMT -5
This is something I need to work on too. Hopefully you'll get some more input from people that do it by hand on glass or sandpaper.
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Post by stardiamond on Mar 16, 2022 15:06:04 GMT -5
I have tried dopping the front to polish the back- with mixed results- works as long as I don't have to get the razor blade to scrape off the wax on the front. But a short dob stick seems to work.
When I try using just my fingers some times the flat lap grabs it out of my fingers & of course, it scratches the front. Much much more experimenting needed - appreciate to hear what works for others.
Patty
I don't use wax and super glue on the face would be problematic. I was freezing superglue and snapping off the cab. More damaged cabs than I would like. I now use an xacto chisel blade to separate and then use acetone and the blade to scrape off the remaining glue. I probably use more glue than others since I want the cab to stay on the dop. I use wheels to sand, pre-polish and polish and it is easier to hold to the cab than when using a lap. The grip on the cab and finger damage is related to the thickness of the finished cab. |
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Post by opalpyrexia on Mar 16, 2022 16:10:27 GMT -5
I have tried dopping the front to polish the back- with mixed results- works as long as I don't have to get the razor blade to scrape off the wax on the front. But a short dob stick seems to work.
When I try using just my fingers some times the flat lap grabs it out of my fingers & of course, it scratches the front.
Much much more experimenting needed - appreciate to hear what works for others.
Patty
You're welcome, Patty.
I really need to remind myself to carefully examine the backs of my preforms for scratches. It isn't quite a habit yet, so occasionally I'm kicking myself when I think I've finished a cab. I've also had cabs slip out my fingers on the lap. One of the two petrified woods that I recently posted slipped out of my hand while beveling the bottom edge. And of course, it bounced face first on the disk before it hit the floor. So it was back to the dop and wheels. Aggravating!! Gotta keep the cab and fingers dry!
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Post by liveoak on Mar 16, 2022 17:37:31 GMT -5
I've always done closed bezels or prongs so really not thought too much about the cab backs, unless it was a nice moss agate and then again it usually was only a pierced setting , so not showing the whole back anyway. But I'm trying to branch out & learn wire woven bezels & hopefully try some groove wraps - so in my opinion the backs need to shine, just like the fronts- hence my frustration (and hopefully determination). I guess I'm the old fashion type stardiamond , it's dob wax for me. You're right, it's easier to hand hold the cab on the wheels then the lap, but as I'm really still learning, as the cabber is pretty new to me, I need every advantage :-)
I've read (and watched a you tube) of people polishing backs by hand with glass or granite plate rockbrain, but somehow I don't think I have the correct Zen brain for that. Especially as my cabbing time is usually limited to after dinner & chores. But who knows maybe someone will post & convince me differently.
Cheers, Patty
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rockbrain
Cave Dweller
Member since January 2022
Posts: 3,179
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Post by rockbrain on Mar 16, 2022 20:21:54 GMT -5
I've read (and watched a you tube) of people polishing backs by hand with glass or granite plate rockbrain , but somehow I don't think I have the correct Zen brain for that. Especially as my cabbing time is usually limited to after dinner & chores. But who knows maybe someone will post & convince me differently.
Cheers, Patty
I'm cabbing outdoors right now. This could be done at my work table in the evening in front of the tv or with some music playing. |
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Post by hummingbirdstones on Mar 16, 2022 20:34:47 GMT -5
Hi Patty, I dop the front of my cabs with wax to polish the backs all the time. I use a flat lap with a metal lap and then resin laps after that. I have tried using wheels to do the back, but I am totally not good at it.  When I want to remove the dop, I just pop it in the freezer for a while and it almost always comes off by itself. Once in a while I'll have to give it a iittle tug, but not often. Any wax residue (if any) that remains comes right off with some denatured alcohol and a Q-tip. |
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Post by jasoninsd on Mar 16, 2022 20:50:34 GMT -5
I must really be in the minority here. I very rarely polish the backs of my cabs. It's not out of laziness...I can promise that! LOL - I don't polish the backs of my cabs because I personally like having the backs look like "natural" rock versus the polished front. I want people to be able to see how much of a difference the working of the stone creates in the piece...
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Post by liveoak on Mar 16, 2022 21:05:18 GMT -5
Thanks Robin, hummingbirdstones, that's about what I thought to do & what I've tried, although I've had mixed results, which is why I'm questioning myself. Need to work at what grit to start with and work through.
jasoninsd I totally understated where you're coming from - keep it natural looking on the back - at that rate it could be actually rough. BUT when it's a translucent stone, I want it polished to be able to hold it up to the light, to see through- that's cool in another way.
I guess it comes down to what we all thing is right for our own art :-) Thanks to you both for weighing in , Patty
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Post by jasoninsd on Mar 16, 2022 21:16:48 GMT -5
Thanks Robin, hummingbirdstones , that's about what I thought to do & what I've tried, although I've had mixed results, which is why I'm questioning myself. Need to work at what grit to start with and work through.
jasoninsd I totally understated where you're coming from - keep it natural looking on the back - at that rate it could be actually rough. BUT when it's a translucent stone, I want it polished to be able to hold it up to the light, to see through- that's cool in another way.
I guess it comes down to what we all thing is right for our own art :-) Thanks to you both for weighing in , Patty
I totally agree with this one...that's why I put the caveat of "rarely". LOL I have polished the backs on certain stones that benefit from the translucency...but not to the full polish as on the front. I've never worked a material that was to the point of seeing through it like "glass"...but when I do, I can see polishing it all the way. As a side note, there's an Agua Nueva cab in this thread that has "faceted" sides to it and was worked all on the wheels...so it is possible to work "flats" on the wheels. forum.rocktumblinghobby.com/thread/98270/biggs-jasper-hematite-nueva-obsidian(That cab was dopped when I worked it...) |
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Post by hummingbirdstones on Mar 16, 2022 21:20:50 GMT -5
Thanks Robin, hummingbirdstones , that's about what I thought to do & what I've tried, although I've had mixed results, which is why I'm questioning myself. Need to work at what grit to start with and work through.
jasoninsd I totally understated where you're coming from - keep it natural looking on the back - at that rate it could be actually rough. BUT when it's a translucent stone, I want it polished to be able to hold it up to the light, to see through- that's cool in another way.
I guess it comes down to what we all thing is right for our own art :-) Thanks to you both for weighing in , Patty
The metal lap I use for the backs is a 180 grit. Sometimes it takes a while on that lap to get saw marks off if there are any, but it's better for me than trying to get 80 grit scratches out. Then I just go through the resin laps -- 325, 600, 1200, 3000 and 8000. I like the back of my stones polished because to me they're not finished unless they're polished. I know a lot of people don't polish the backs of their cabs, but I'm kind of anal about it. |
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Post by Rockoonz on Mar 16, 2022 22:08:54 GMT -5
When doing flats, I usually start with 180 or 220, depending on how flat it is to begin with. If I see saw marks I put it on the lap so it will grind at 90 degrees to it so I can see the progress. I also don't move them much as they tip slightly when moved around and don't get to the middle of the flat as well. When changing grits I turn 90 degrees again, and unless it's really soft I do everything finer than 600 on the Genie wheels, sand and spin.
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Post by jasoninsd on Mar 17, 2022 1:02:02 GMT -5
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Post by liveoak on Mar 17, 2022 6:11:12 GMT -5
Thank you hummingbirdstones for the exact routine you do- just what I was hoping for, and plan to order some resin flat discs, for my end lap on my cabber.
Rockoonz I LOVE the 90 degree turn when changing grits on the lap. I know this trick when sanding and it never clicked to do that on the lap.
Thank you for the reminder.
jasoninsd Your faceted Agua Nueva cab is beautiful (heck they all are) and yes I see what you mean that you can grind a "flat" on the wheels, but for the whole back, I just like the idea of using a flat disc vs the wheel. But then it depends on how flat it needs to be.
I've read in the archives on "polishing backs" and you're right, things haven't changed at all. Everyone has their own idea of what they like.
I started this thread to see if anyone had concrete techniques they were using presently that worked & I got just what I asked for! Thanks everyone for your input.
Patty
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