jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 6:29:59 GMT -5
Ten 30 grit diamond pads arrived. 30 grit for coarse grind. $20 for 10 units ppd. www.ebay.com/itm/171708091241?_trksid=p2057872.m2749.l2649&var=470670996239&ssPageName=STRK%3AMEBIDX%3AITIntend on gluing(epoxy) 1/6 pie shapes together after grinding velcro backing off whole pad with bench grinder. Easier with whole pad. 1/6 chosen because there are straight line gaps that allow use of scissors for easier cutting. Grind backing off first, then cut, then glue w/30 minute epoxy. The stack: 10 pads, 60 one sided pie segments. After gluing, 30 double sided segments. For 8 pound barrel. These are the scrap center hole punch outs. Note 30 grit diamonds are mostly covered in plastic. An initial 24 hour run in SiC 30 will expose the diamonds. A one time run with SiC. I hope to start an 8 pound barrel up today with freshly broken sharp agates. I will run them at a fast 55 RPM in a 6 inch PVC barrel. I will use sticky clay because I believe the cohesive forces increase grind pressure and maintains a connection between the rocks. And lubrication. I feel that this is going to work. Hope the pads last a long time. Will post photos of progress and grind rates.
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Post by MrMike on Feb 8, 2017 7:24:17 GMT -5
Well hurry up....I'm out of -&@:%€ coarse grit yet again!!!
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Post by captbob on Feb 8, 2017 9:52:59 GMT -5
Wonder if a overnight soak in acetone (pick your poison) would remove the velcro backing. Can you cut those pads with tin snips?
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Post by Garage Rocker on Feb 8, 2017 10:03:46 GMT -5
Great experiment, looking forward to the results. I could have done without that last photo though, something disturbing about it.
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Post by wigglinrocks on Feb 8, 2017 10:24:39 GMT -5
Hope this works , sure would save a lot of time and grit bucks . I am somewhat skeptical though about there longevity , hope I'm wrong
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 10:29:43 GMT -5
Great experiment, looking forward to the results. I could have done without that last photo though, something disturbing about it. My wife just looked at it and puked, me laughing at reaction
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 10:40:43 GMT -5
Wonder if a overnight soak in acetone (pick your poison) would remove the velcro backing. Can you cut those pads with tin snips? NO ! Tell you why Bob, 24 hours with SiC 30 in rotary w/rocks exposed the diamonds per excellence. Guessing 48 hours with SiC 46 or 60 would do the same thing. You don't want to compromise the plastic matrix by softening it with a chemical. It is a very hard plastic and the best scenario is to have it hold the diamonds with the best possible grip. I believe the exposed diamonds will prevent fast wear on the plastic. I am sure you can cut them with snips. But just cutting between the squares ruins the scissors. Diamonds tore my scissors up cutting one 100 grit pad up. so use old scissors or snips.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 10:49:51 GMT -5
Hope this works , sure would save a lot of time and grit bucks . I am somewhat skeptical though about there longevity , hope I'm wrong I was impressed with 24 hours with fresh SiC 30 to break them in. However, after that you will not need to add SiC and there will not be those hard sharp grit particles attacking the plastic. You will run them with rocks only. Should reduce wear a lot as opposed to running the SiC. Should the diamonds fall out or get dull(I doubt it) you can 'dress' the pads with another dose of Sic. I used these pads on grinders. They are tough customers. Long lasting. Except on concrete that sheds sand particles. The sand particles roll between the diamonds and eats the plastic away. The exposed diamonds wards off wear on the plastic like a bulletproof vest on non particle producing Mohs 7 rocks. Like I mentioned earlier, I have been using the same 100 to 3000 grit pads on hundreds of lapidary slabs for over 10 years.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 10:55:53 GMT -5
Hey, I'm in my element experimenting. But hope these pads shred our rocks and get the heck rid of SiC. And last many grinds. And reduce clean outs.
they may be hell on tumbler barrels....
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Post by wigglinrocks on Feb 8, 2017 11:07:03 GMT -5
I'm not really doubting they will work , it is just a totally new concept that I seem to be skeptical until it is a proven system . I think the pad size will play a role in how they work with different size material . How would a wide wood chisel cut the pads ? Definitely watching with interest , not doubt . These experiments are just some of the reasons we all have you , and hope to keep you around for many more years .
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 11:51:53 GMT -5
Took 27 minutes to remove backing and cut into 1/6's. I opted for the man eating 8 inch wire wheel to remove the velcro pubics to avoid heat buildup that melts them into a mess. Next step is to glue. Then grind edges smooth after dry(Or tumble them smooth). Not sure about clamping scheme. Mass clamping a must. Non-OSHA man eating wire wheel Velcro removed Quantity 60 1/6 pies and scissors dulled to maximus. Will only be 30 when glued together. Hope to use 30 minute or 1 hour epoxy. Represents 120 square inches of grinding surface. 10" X 12".
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Post by MrMike on Feb 8, 2017 12:13:24 GMT -5
Great experiment, looking forward to the results. I could have done without that last photo though, something disturbing about it. From China, you know the carpet/drapes analogy...
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 12:20:38 GMT -5
Or the gal doing a table dance over your Martini
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Post by HankRocks on Feb 8, 2017 13:41:27 GMT -5
Bet that Wire Brush Wheel could do you nails.....right down to the bone!!
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Deleted
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Post by Deleted on Feb 8, 2017 14:34:34 GMT -5
Curious you didn't glue them while (less tedious) and the. Cut with bandsaw after.
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jamesp
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Post by jamesp on Feb 8, 2017 16:26:10 GMT -5
Curious you didn't glue them while (less tedious) and the. Cut with bandsaw after. Bandsaw will get dull quickly if the blade looked anything like the scissors. No matter, I am going to try the 10mm thick pads to avoid tedious glue job. Read what it did to my 14 inch abrasive cut off saw. It cuts anything. Not this stuff.: Cut these two 100 grit pads that are glued together with a 14 inch abrasive metal cutting saw. 5000 RPM beast, cuts railroad track in half. Well, these pads glazed the saw blade in short order. It took a lot of effort to cut these. I had to cut metal 4 times to shear off new grit(like dressing a saw or grinder). Rounded edge after 24 hours in a rotary at 55 RPM with a fresh charge of SiC 30 grit. Before: After, note rounded edge: These are cheap $1.60 pads. Counting diamonds here. Looks like 12-100 grit diamonds on one 3/16" X 3/16" block. Maybe expensive pads have a higher diamond density. Don't think it matters. They may all have 30 carats per pad. The tumbling did a major change in exposing the diamonds in the virgin pad. And did not seem to knock any diamonds out due to impact at a fast 55 RPM. Important. The diamonds are so sharp that they scratched this agate easily with the weight of this stone. It is the size of 4 quarters stacked on each other. This is critical. Cutting rock with very little pressure.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 16:36:31 GMT -5
Bet that Wire Brush Wheel could do you nails.....right down to the bone!! Fear the wire brush. 2 HP grinder with no guard, shame on me. Nothing worse than getting flesh removed with a wire brush. I brush a lot of 1-4 foot steel and need it open.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 16:47:42 GMT -5
On a side note, check out this fine home made vibe media. It was slabs of hard/solid/ no fracture coral broken with a hammer and rotary tumbled. Green seaweed is aquatic bladderwort from water supply for tumblers. closer up, 1/4" holes for size reference.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 16:58:34 GMT -5
This is what went into the 7 pound capacity tumbler today less about half of the coral media on right. Added a cup of clay and 1/2 cup SiC 30 to break diamond pads in. Rolling at 55 RPM. Let's see what happens. Mohs 7 agates and woods not tumbled, sharp.
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jamesp
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Member since October 2012
Posts: 36,555
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Post by jamesp on Feb 8, 2017 17:07:45 GMT -5
Glue operation was a pain. Will try 10mm thick pads to avoid PIA glue process. Used 5 minute epoxy due to lack of clamps. Final product. epoxy ground of with bench grinder.
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