jamesp
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Post by jamesp on May 15, 2013 5:57:48 GMT -5
Thanks Larry.Never know till tried....
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Post by helens on May 15, 2013 6:46:28 GMT -5
Interesting interesting thread! Just found it today too because you bumped it up.
My thoughts had I read it from the start would have been that it wouldn't work so efficiently for a couple of theoretical reasons (I don't own a rotary tumbler, only a vibe). 1. the diamond bits while grinding would be encountering other diamond bits and self destructing at the same rate it's grinding down the corals.... attrition would be terrible unless you were getting a super cheap/free source of diamond bits.
2. The reason grit works is because it's evenly coating the surface of each rock, and the rocks rub against each other. The only reason the grit breaks down is because it's also rubbing against ITSELF, which is harder than the rocks it's breaking down. That surface coating is critical for even grinding, because the rocks being ground do the work... fewer diamond bits would result in less surface area, so it would seem that in a rotary, you'd have more fractures and damage from rocks HITTING each other, with no cushioning of surface coating, with less efficient grinding action, because there are fewer diamonds than grit. 3. Diamonds are hard... but they are brittle. You can cut things with diamonds, but they aren't more effective when smashed against each other. You can shatter a 10 MOH diamond easily with a 6.5 moh steel hammer. Dropping diamonds against each other in a tumbler would seem to damage the diamonds as much as the coral. And you don't need to be MUCH harder to grind, just a little harder... going much harder wouldn't seem to provide extra grinding power or speed, because the surface area of the diamond is still the same size as SC grit, it can only take that much off at a time.
4. if I think about it, the IDEAL grit to use would be anything that is harder than the stones being tumbled, but which are also somewhat flexible (for a rotary especially)... like steel- anything that won't break if hit. This won't prevent it from breaking down tho from rubbing against itself.
Now that I think about it more, seems like steel flakes/powder would work more efficiently with softer stones than the grit. For a 7 MOH coral, you'd need a 7.5 or 8 moh flexible sandy substance, and steel wouldn't do it because it could be softer than the coral... but only in a vibe tumbler, which is a direct stone to stone rubbing, vs rolling and dropping.
I still think the fastest way to work a stone is to shape it fast on a coarse grinding wheel, then vibe tumbling, since the entire process from start to finish is roughly a week. You just cannot do large quantities this way.
But... you have access to a lot of steel fragments in your metal work... have you tried throwing in a few handfuls of steel filings instead of grit, and using the same process as using SC? If you can get it free, that would be an interesting experiment (the hardest strength steel filings, I think iron would be way softer).
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Post by helens on May 15, 2013 6:49:24 GMT -5
Just realized... probably the fastest possible way to finish corals is to do the diamond saw blade 'stacking' (use like 6-8 diamond blades with a couple of spacers in between each blade), for fast shaping of the coral, that should shape each piece in seconds, then vibe tumble for finish. If I had volumes of stones to get through, that's how I'd do it.
This would give you the added bonus of control over the shapes also.
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jamesp
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Post by jamesp on May 15, 2013 7:47:12 GMT -5
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Post by helens on May 15, 2013 8:02:44 GMT -5
Something is wrong with your link, it won't show a pix. Can you relink?
The coral WOULD eat up a diamond grinder wheel... that's why I thought stacking diamond saw blades might work better...
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jamesp
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Post by jamesp on May 15, 2013 9:16:08 GMT -5
Try images then Starting coral one minute later This is cat's meow for coral Helen
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jamesp
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Member since October 2012
Posts: 36,563
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Post by jamesp on May 15, 2013 9:28:18 GMT -5
More pics Major dust after one session.Done outside of course.Next to pressure washer for clean-up. Here is like the first cab i made on that finger eater the other day Close-up
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Post by helens on May 15, 2013 9:33:00 GMT -5
Oh wow... that does look good. What's the hardness on the blade?? What IS that blade?
I'm a tool idiot, so I have no idea what I'm looking at, but I can see that working pretty well:)!!! And that last coral is gorgeous!!
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jamesp
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Post by jamesp on May 15, 2013 9:41:31 GMT -5
This is a diamond grinding wheel i have used on coral for many years.The used to be $100.I see them for $12 now.It lasts about 200 pounds of tumbles.I am a pregrind freak.The hand grinder is similar to your husband's that you guys split coral with except it turns slower at 3600 RPM.I need to go about one third that speed,say 1200rpm. www.harborfreight.com/4-1-2-half-inch-diamond-turbo-cup-wheel-98729.html
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jamesp
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Member since October 2012
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Post by jamesp on May 15, 2013 9:51:27 GMT -5
This is a field grinder for looking inside of coral without destructive hammar blow.Same diamond cup wheel mounted on motorcycle starter motor.Can't wait to use it.
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Post by helens on May 15, 2013 9:56:44 GMT -5
See, my big concern with that would be dust.... I don't like wearing a mask, nor would I remember to, and I'm sure not adding to my potential for COPD or Emphysema on top of my bad smoking habit:).
The reason I thought the diamond blades would be more efficient is because you can use them with water to keep the dust down. The setup you have wouldn't work for me, just because of the dust.
I've agonized about how to polish slabs the best way, but keep coming back to the dry SC belts on the expando, because nothing else seems to work as well or as quickly.... but I'm afraid to try it because of the dust:(.
Plus... with corals, it's probably not such an issue, but a lot of other stones have REALLY bad components, from inhaling asbestos in malachite/chrysocolla to arsenic in bumblebee. That kind of dust, even marginally lingering could potentially be really dangerous.
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Post by parfive on May 15, 2013 11:26:04 GMT -5
Helluva switch.
Whadya, put a rock on it? ;D
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jamesp
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Post by jamesp on May 15, 2013 11:29:51 GMT -5
I eliminate dust now Helen.By dip and grind.I don't really care,i stay upstream from the dust.And i clamp the garden hose with fine spray if it is calm.Actually,the grinder in the photo has a water center feed that comes from a hole in the center while it is turning.That is a wet grinder for finish polishing granite couter tops with velcro diamond pads.I smoked from ages 15-53-2 packs a day and healed OK.I had to stop for medical reasons and other Aggressive is what is needed for a lot of coral work.Love them diamond cups.I am looking into slow moving 16GRIT diamond cup wheels for faster removal. Ya never know what a rock has in it.Or has absorbed.
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Deleted
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Post by Deleted on May 15, 2013 17:56:07 GMT -5
Helluva switch. Whadya, put a rock on it? ;D lol...... no silly, coral! HA!
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quartz
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breakin' rocks in the hot sun
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Post by quartz on May 15, 2013 18:18:28 GMT -5
Man, that is some nice mtl., very unique to us. Looks like a nasty crust on it. Larry
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Deleted
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Post by Deleted on May 15, 2013 18:52:37 GMT -5
you can put all the copper in the water you want without an acid to break it down you will only have copper.
Sulfuric acid = copper sulfate hydroclhoric = copper chloride
voyez-vous mon idée ici
Add baking soda to make pH 8+ copper is tremendously stable.
Iron will oxidize in water thru electrolysis. Add the baking soda to stop that too!
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jamesp
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Post by jamesp on May 15, 2013 19:15:04 GMT -5
Just touch that switch for a second parfive and that starter motor instantly hits 5000 RPM.Then it takes a long time to coast to a stop due to it's rotational weight.Or stop it with grinding operation.
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jamesp
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Post by jamesp on May 15, 2013 19:22:33 GMT -5
That is some typical coral lense chipped off the top of a coral.The acidic water probably dissolved some of the limestone away leaving the silicification.The indaians remove the skin trying to get the usable core out of a coral head.They left behind great tumbles and cabbables in the process. That coral is very sharp and must be respected when snorkling or walking in the river.Usually wear highleather boots and a bathing suit-very sexy.
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jamesp
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Post by jamesp on May 15, 2013 19:26:13 GMT -5
Should i charge money for those witty statements Scott?
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Deleted
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Post by Deleted on May 16, 2013 11:55:19 GMT -5
Should i charge money for those witty statements Scott? They are worth every cent we pay!
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