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Post by idahocollector on Jun 30, 2018 19:18:17 GMT -5
I just joined this forum after spending a few days reading over some past posts on this site regarding polishing slabs using handheld polishers instead of a flat lap. Please note I am new to lapidary, just getting started, and I am researching the best tools to buy to polish slabs for display quality results. One of the reasons I have decided to look into handheld polishers instead of a flat lap is that many of the slabs I have are thin, high grade material, have some fractures and may not survive the necessary weighting/jostling in a flat lap. Given that, here's some questions for any who can offer answers:
1. Has anyone used the King Rotoblast (http://www.rotoblast.com/wet_polisher_stone_polisher_p/rotoblast%20m-100k.htm?) for polishing slabs? I read a post on here of someone asking about it but no followup. The alternative suggested was a Barranca, from Barranca Diamond, but these are 3x the price of the Rotoblast. The Rotoblast has pads that only go to 3000 grit, whereas the Barranca ranges to 13000 grit but I am assuming I can make my own pads and I am wondering if anyone has done this for either tool. The lower RPM and weight of the Rotoblast is also a nice feature. I plan to use this on a flat surface outdoor with a rubber warehouse mat to hold the slab.
2. If anyone has made their own pads for these handhelds, where did you get the material to do it? Any pointers appreciated.
3. I also appreciate any ins/outs from someone who has used these to polish slabs to display quality, mainly on how to avoid breakage from the process. Most of the materials I plan to polish are fine agates and jaspers, and some Dino bone. The size of the slabs range from 4" to 14", thickness as low as 4mm on some.
Thanks in advance.
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vwfence
has rocks in the head
Member since January 2013
Posts: 564
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Post by vwfence on Jun 30, 2018 20:01:47 GMT -5
I have an inexpensive one from Amazon that I have had 3 or 4 yrs . One thing I found was by taking a piece of plywood and covering it with the cheap shelf liner that is like a mesh , it holds the slabs from slipping pretty good . I buy the 4 inch diamond pads in varying grits on Ebay and I make my polishing pads from a cheap carpet runner that is like a thick felt . I tried one out of leather , but without putting Velcro on it it didn't want to stay on
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Post by woodman on Jun 30, 2018 22:11:52 GMT -5
I use hand held harbour freight var speed polisher with the 4 in dia diamond pads and use a 7 in pad with wool carpet on it with cerium oxide for polishing. i don't like the polish of just using thr diamonds disks alone. this is on larger petrified wood slabs. it is not fast but it works.
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vwfence
has rocks in the head
Member since January 2013
Posts: 564
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Post by vwfence on Jul 3, 2018 22:10:43 GMT -5
I have a harbor freight 7 inch unit that I built a mount for and use it as an angle polisher with the 7 inch pads
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Post by rmf on Jul 4, 2018 18:18:52 GMT -5
I have s similar but slightly different machine that I have used to polish P. wood log sections and a KY Agate Geode for a customer. MY first attempt went poor because it takes a while for the diamond pads to be broken in especially as the grit gets finer. (I was too impatient but now they are broken in and they work great) I have not made pads it is cheaper for me to purchase them. The ones I purchase locally have a velcro back (hook and loop) and attach to a pad with hools. works great. There is not much reason to get diamond pads finer that 8000. the human eye can't see the detail. If you make it to 8000 grit and you want more of a polish use a standard cerium or tin oxide polish and a leather/muslin buff.
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Post by stardiamond on Jul 4, 2018 19:43:50 GMT -5
I am going to keep an eye on this topic. A project that I have been considering for a long time is a chessboard with 32 dark and 32 light squares made with similar hardness jaspers and agates. I thought it would involve cutting and polishing 64 square cabs.
I made a chessboard in HS over a half century ago and the technique was to glue together alternating light and dark wood, cross cut and re-glue staggered and then use a belt sander on the board. I don't think this would be practical with smaller slabs, but I could cut out 64 squares on my trim saw that were all around 1/4 inch epoxy them together on a waterproof backing, then use a hand held wet polisher and then frame the board using picture framing material.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Jul 8, 2018 17:36:28 GMT -5
I bought a Makita wet polisher. I works, but is not particularly fast, and you get drenched, so I've hardly used it.
It seems to have problems dealing with the outer edge of the slabs. I thought about gluing a bunch of slabs together into one big surface, every slab perfectly level, but haven't gotten around to it.
I'd suggest that most people polishing any quantity of slabs are using big vibratory laps, generally, though there are lots of options. The process isn't really violent; cracks can always be zapped with crazy glue, or you could back the slab with plywood, or epoxy and fiberglass mesh tape if need be.
Stardiamond, a wet polisher is what you'll need, but for you the work will be in getting each square truly square, and gluing them up so that each is perfectly flat. One low corner on one little square means you get to grind the entire slab down to that level, which will be unpleasant. Stone chess boards aren't unusual on the market, but they're typically softer stones like alabaster, and produced in countries where labor costs are low.
Hope this helps a bit.
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Post by woodman on Jul 8, 2018 20:35:17 GMT -5
I have a wet polisher/grinder. I used it for contour polishing large pieces of pet wood. for large pet wood slabs i just use a harbour freight variable speed polisher with 4 inch diamond pads, and hand held water spray bottle. you really don't need all that much water, but you still need a rubber apron and lots of time. Not for a production shop by any means, but it works for this old poor boy!
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