mikeinsjc
spending too much on rocks
Member since June 2010
Posts: 329
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Post by mikeinsjc on Sept 24, 2017 13:58:46 GMT -5
You know, I have never been able to understand the popularity of vibrating laps. They have to be the most poorly thought-out tool ever created. Now before you get all worked up and take that criticism personally, I would say I have probably used them more than most lapidaries. I have owned a 16" Covington, two 27" HPs, a 20" Beacon Star, and a 20" HP. At times I've had three running simultaneously. I've ground and polished thousands of specimens, so I feel I am very qualified to call them pieces of junk. The Beacon Star was the only unit you could remotely think about leaving unattended. Those of you that have used the big HPs know how quickly those things can go south.
Why do they remain so popular? They are slow, messy, noisy, require much babysitting, and aren't cheap. Any tool, in any other profession exhibiting those negatives would never sell. It's not as if the technology doesn't exist to make something better. I paid about the same for my custom-built 36" rotating lap as a 27" Diamond Pacific costs new, and can polish at 5-10 times the volume is the same amount of time.
OK, I get that not everyone has the space, the spouse, or the $ for such a big unit. Which begs the question: Why aren't more rotating flat lats being produced commercially, in all sizes? I think there is a great market here.
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doublet83
starting to spend too much on rocks
Member since March 2016
Posts: 118
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Post by doublet83 on Sept 24, 2017 14:33:11 GMT -5
I'm a newbie that bought a covington vibrating flat lap so I can probably provide provide some insight into why they are popular: they're the cheapest widely available option for polishing a flat face. That's why I bought it.
I agree with all your complaints here, and I regret my purchase. They do require a lot of babysitting, and they make a mess. I haven't been able to get it to produce a good polish, and the work cleaning up the lap and the rocks is a huge pain. Frankly, its not enjoyable and feels highly inefficient to me, so the lap sits there unused.
As far as I can see, the other options for me to polish flat faces are either flat laps or a bull wheel. Not knowing enough about how well these machines work makes me hesitant to avoid another bad equipment purchase.
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Post by captbob on Sept 24, 2017 14:49:03 GMT -5
I agree with the slow, messy, noisy, but wonder about what require much babysitting means. I do go check mine every 6 to 8 hours or so. If I'm not going to be around, I hit the on/off switch and start it back up when I return. No biggie. Every 6 to 8 hours is more babysitting than I care to do, but it's not an every hour or two thing. Every 6 to 8 hours is enough to keep me from using a vibe tumbler, but I will put up with that to use the vibe laps. odd
Would LOVE a large rotating lap (with an overhead sweep gizmo) lack of space is slowing my getting one.
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mikeinsjc
spending too much on rocks
Member since June 2010
Posts: 329
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Post by mikeinsjc on Sept 25, 2017 11:56:05 GMT -5
Well, I apologize for that jerky-attitude post. Must have been in a bad mood. I know they fill a niche. I guess my main beef is with the design of the HP units. Having the pan rest on plastic balls like the Beacon Star is a much more sensible design.
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Post by captbob on Sept 25, 2017 12:17:26 GMT -5
I agree, the supported pan just seems more logical than the suspended pan - to me. My Raytech 15" vibe laps are sitting on balls as well.
And yes, they are slow, and messy and noisy and generally more trouble than they are worth! But that's all I have for now.
I need to get the flat lap I got off craigslist up and running. That machine seems the best way to quickly face polish the ton of coral I want to do. A horizontal belt sander (Covington makes one) might be fast as well, but I don't have one of those either. (need more room!)
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minerken
Cave Dweller
Member since August 2013
Posts: 466
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Post by minerken on Sept 25, 2017 15:11:28 GMT -5
I have often thought about the vibratory flat laps and can understand what you are talking about. After a lot of thought I like the idea of a reciprocating lap over either the vib or rotary.I don't have any of the three but one is on my bucket list of things to build.I think that you could actually make a 2 in 1 machine using the rotary and the reciprocating approaches. Granted the recp. machine would be more aggressive and the slabs may need to be cushioned on the edges. The action of the reciprocating would also produce differential grinding back and forth and the slab will also tend to rotate if not packed too tightly.
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Post by HankRocks on Sept 25, 2017 15:16:26 GMT -5
My big issue with vibrating laps is knowing if I have all the saw marks removed in the coarse stage. No matter how much I check, almost always find one or two that get though my inspections and not be discovered until they are in the polish stage. Have decided that if I am running a batch of 12 to 14 rocks, If I miss 1 or 2 and have to re-start them, no big deal. I do use 4 pans, one for each stage so pan cleanup is not as critical. Only checking about every 4 to 5 hours and then to add water or a bit of grit. When I leave, the machine gets turned off. For the bigger pieces of petrified wood, I have started polishing one end, cut about a 3/8" of the polished end off and then start the process all over. I am on my 5th and last cycle on nice piece of wood. Henry
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,179
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Post by jamesp on Sept 26, 2017 7:09:51 GMT -5
Rotary for coarse work, vibe for polish ? Maybe that does not work for laps. Just thinking out loud.
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Post by roy on Sept 26, 2017 10:14:29 GMT -5
i have them as well and hate them too but even my 36"rotory needs constant attention !
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Sept 26, 2017 11:02:06 GMT -5
My big issue with vibrating laps is knowing if I have all the saw marks removed in the coarse stage. No matter how much I check, almost always find one or two that get though my inspections and not be discovered until they are in the polish stage. Have decided that if I am running a batch of 12 to 14 rocks, If I miss 1 or 2 and have to re-start them, no big deal. I do use 4 pans, one for each stage so pan cleanup is not as critical. Only checking about every 4 to 5 hours and then to add water or a bit of grit. When I leave, the machine gets turned off. For the bigger pieces of petrified wood, I have started polishing one end, cut about a 3/8" of the polished end off and then start the process all over. I am on my 5th and last cycle on nice piece of wood. Henry Simply draw on the surface of the stone with an aluminium wire. The silver marks will disappear when the saw marks do. Colored pencils work too.
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Post by HankRocks on Sept 26, 2017 12:25:47 GMT -5
I have tried that method with not much success. The marks I put on all went away but there were still missed spots, maybe I did not have enough marks. Maybe I need to coat the whole surface of the rock with something. The problem is that holding the rocks up dry and trying to use lights and glare to check the surface does not work until the rock has gone thru the 600 stage, the contrast is finally visible. Note - these are not deep saw marks, those I can see easily after coarse, it's the faint ones that seem to get by me.
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Sept 26, 2017 17:44:31 GMT -5
Yes, lots of marks. Many many marks.
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