ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 14, 2008 16:09:48 GMT -5
What a drag. I've been working on a mixed rock tumble for months, slowing working my way through each stage. I ran them through a 10 day AO polish this week. They came out pretty good, not as amazing as some of the ones I see in this forum, but the best I had ever done. I wanted to finish up with a Borax/Ivory burnish to try to get a bit more shine. I put the rocks in the barrel along with a bunch of new plastic pellets, 1 TB each of Borax and pure Ivory soap flakes (made by grating a bar of soap), and water. I was going to be away for day 2, so I decided to run a 3 day burnish. I was shocked when I opened the barrel this morning and found lots of damaged stones. New chips in the amethyst. The labradorite was ruined, with lots of grooves and pits. Everything looked dull. Just trashed. I was pretty bummed - all those months and this is what I get at the end! But then I remembered: hey, they're just rocks, now you get to tumble them again! I sorted them, sending a few back to rough, a bunch to medium, and the rest to the 500 SC pre-polish. Hopefully running them back through will fix whatever problem I had and they'll be fine in the end. What caused the rocks to get ruined in the burnish? There were a lot of brand new plastic pellets, so I don't think that a lack of padding was the problem. Cross-contamination of grit is unlikely as I used a brand new barrel dedicated to polish and had washed all the rocks for 24 hours in Borax after the pre-polish. My best guess is that the problem was in the mixed nature of the rocks. During the burnish, which I ran for a long time, maybe the harder rocks damaged the softer rocks despite the pellets. Perhaps that is why the labradorite (Mohs 6.0-6.5) was the most damaged? Any other ideas? I feel like such a newbie doofus! I'll get another try (10 days pre-polish, 1 day wash, 10 day polish) but it will take about 3 weeks!  |
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Sept 14, 2008 17:03:58 GMT -5
Amethyst and Labradorite are unfortunately some of the most delicate stones to tumble, with either of them I would stop as soon as I think they are OK, but I and many others have had like zero luck getting those stones to hold together all the way through tumbling.
Re-cycling might help, but don't be surprised if even that proves counterproductive on some of them...
I am reluctant to "burnish" or borax/ivory in a final polish unless there is an inordinate amount of oxide left over after a rinse and hand microfiber buffing- if they look good with that why even take a chance of messing them up?
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lsmike
spending too much on rocks
Maxwell's demon lowers tumbling entropy
Member since January 2007
Posts: 468
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Post by lsmike on Sept 14, 2008 17:52:39 GMT -5
My first piece of Labradorite scratched and chipped in 800A.O. in a vibe,probably because I had hard stuff in there too.I assume you need ALL the load to be "soft".Either that or grind and sand by hand.Mike.
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buckwheat69
noticing nice landscape pebbles
How do we get out of here ??
Member since July 2008
Posts: 96
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Post by buckwheat69 on Sept 14, 2008 18:33:18 GMT -5
Ah man that really stinks. sorry to hear that. I have my first tumble going (2nd week of coarse). Which contains both Amethyst and lab. with a mixes of other from 7.5-6 Moh's, looks like i should separate at the grit change (Now you have me all worried LOL).
is this a problem many others have had?? I to am interested in any suggestions
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Roan
has rocks in the head
Member since January 2008
Posts: 600
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Post by Roan on Sept 14, 2008 18:43:04 GMT -5
Is amethyst a lot like citrine to tumble? I'm wondering if it's the source stones that really matter. Internal fractures and stuff? I've tumbled huge batches of both -- mixed with other stones -- and never had a problem going through burnish stages. Course, I could have just been lucky.
I got both my citrine and amethyst from The Rock Shed.
Labradorite has given me problems, though. Darn stuff.
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Post by cpdad on Sept 14, 2008 18:46:16 GMT -5
amethyst has caused me more problems than any other material in the rotary tumbler.... like rally said it causes a lot of folks a lot of problems....and it is mostly problems just like you are having.
i would not run amethyst with any thing softer whats so ever past rough grind.....you could run it in the rough stage with others ....and cull your rocks as they are ready....then save enough of it to run by its self thru other stages....but i have found it breaks along diff stages anyway....sometimes i think there are pieces that are actually harder than mohs says ;D.
here is what usually happens after rough grind.... to me anyway.
during any stage after the rough grind if you have amethyst in the tumble and a few pieces decide to chip....the whole load is done...ya gotta start over....if you have any softer stuff in the tumble they really get beat up...the sharp edges on the amethyst wreck havoc on every dad burn thing in the load...kinda like you throwed some 60/90 in the load....and this can happen in any stage of a tumble.
your burnish had nothing to do with it....thats just when the amethyst say hey...im gonna break and mess up this load ;D....im really surprised the labradorite made that far anyway.
i believe it was nmrocks that coined amethyst....the devils rock....for it acting similar to what happened to you....kev.
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Post by Jack ( Yorkshire) on Sept 15, 2008 2:36:33 GMT -5
Hi
Interesting no one has mentioned speed ?
Most run at a faster speed in stage one then slower in the folowing stages and polishing.
I had a simular experience with Amy when I first started and my barrel was running to fast (about 55RPM)it shattered a good batch
I run them through at around 40 RPM now and havent had many Amy shatter or fracture above that speed expect trouble
Laborite ?? I have some low grade I Vibe , but thats a lot gentler than tumbling in a rotary
Jack Yorkshire UK
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 15, 2008 6:13:43 GMT -5
As far as I know, I cannot adjust the speed of my Lortone tumblers...
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Post by connrock on Sept 15, 2008 6:36:47 GMT -5
I think your problem is twofold. One is the amethyst itself being a bummer to polish and the other is the burnish with amethyst and labradorite being left together for too long. I "think" the soap/borax has "eaten" away at the labradorite as if you were to scrub it with the "grain" using a toothbrush.The soap/borax mixture actually washed away (eroded) the labradorite and caused it to destroy itself. The amethyst,as Jack said,may have been turning too fast for too long a period of time. A burnish is a good thing is it is used properly and letting it run longer usually ends up in a mess,,,especially with a sifter material. Even if you do the labradorite by itself a burnish may just erode it again. If you have probs with amethyst you may want to thicken the load a bit .There are several ways to do this.Sugar,Caro Syrup,Hair Jell,Oatmeal,Shredded news paper,saw dust,and the list goes on and on. I am doing about 8lbs of chevron amethyst right now.It is a gift to a young man and woman to use as favors at each table at their wedding. Here are 2 photos of it before roughing,,,,,,  Here you can see how rough it is,,,,,,  It has been roughing for about a month in 46/70 grit with 2 grit changes.Iopted to do it in 2 tumblers.One is a 6lb Lortone and the other a 4lb Lortone. One "trick" I've learned when doing some of the more delicate materials in a rotary is to use MUCH less water to start with. For example in the 6lb tumbler I only put about 3/4"-1" of water in the bottom of the barrel after I have the rocks/grit in it.I tilt the barrel a tad to see how much water is in it. In about 24 hrs you MUST check it or your dead!! You WILL hear that clunkity clunk and you had BETTER get a LITTLE more water in it.About another 1/8"-1/4" of water at the VERY most.Let it run for another 24 hrs and do the same but be VERY careful to not add too much water. Soon you will have created a THICk slurry and "this" is what slows down the action in the tumbling barrel. I have to say that there is a fine line between a thick slurry and a slurry that is too thick but when you do this for a while and "listen" to the barrel as it turns,you WILL hear it telling you what it needs! I finish 99.9999% of my rocks in a vibe but if you use this same technique throughout the entire tumbling cycle it should work just fine for you. OOPS,,,In the polish stage you may have to run only 1/2 of the rocks at a time.Use 50% rocks and 50% plastic pellets. Remember now,,,,this is "my" recipe and others do it using their "recipe" which will also work for you. Good luck!! connrock Ps;The amy should be finished roughing today and I'll take a few photos of it. |
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Post by sparkles on Sept 15, 2008 6:37:08 GMT -5
So sorry you had a duff final stage EJS. My own experience of the burnish process is exactly the same, I've tried pellets, padding, thickened media, and finally decided that my pebbles are as shiney as they will ever get after a thorough washing post polish and a good buff with a soft cloth. In my humble opinion the burnish stage is rarely of any value, and I've only ever managed to degrade rather than upgrade a stone by trying it. However - the re-tumble should give you a pay off in the end!  Good Luck! Sparkles. |
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Post by connrock on Sept 15, 2008 15:32:30 GMT -5
Hi again, I finished roughing the amethyst today and took a few photos for you to see that there are no fractures even the tiny pieces that were tumbled. They were in 47/70 grit for about a month with 2 grit changes.     I put them in a vibe with straigh #220 grit today.I will wash them and re-do them again in the #220 tomorrow. Hope this helps a bit. connrock |
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 15, 2008 17:44:03 GMT -5
Very helpful, conrock, thank you! I'd love to see more photos. My mother-in-law really likes tumbled amythest, so I've started a big batch for her Xmas present. Here is the rough I started with:    I started with 5 lb. of rough. I am tumbling in 60/90 SC grit with a wash/recharge every 6 days. Since I have a bunch of rough, I am actually running some experiments: measuring the weight of the rocks before/after as I vary the tumble specs. I expect it to take a few months to work my way through all the coarse shaping. Having a bunch of it will also allow me to keep the amythest homogenous through all the stages. Hopefully I'll end up with better results this time! I'll let you know in a few months... |
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181lizard
Cave Dweller 
Still lurking :)
Member since December 2005
Posts: 2,171
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Post by 181lizard on Sept 15, 2008 19:22:40 GMT -5
ejs...I'm by no means an expert but you axed so I'm gonna give it a go... When you said labradorite...I kinda shuddered. From everthing I've read, it can be a real bear. Softer than most. If not cut/fractured/split or sawn in the right direction...your entire batch can be tossed. It can end up just being a very dull grey mess. I myself wouldn't try to tumble anything other than the odd piece here & there because of the cost & you should probably have some experience with it. If anyone dissagrees...please chime in. As for amys...some have decent luck...others have no luck at all. I feel alot depends of the quality of your rough...how it was made small enough to tumble.(hammered will make a mess with fractures unless you really know what you're doing.) I wouldn't blame the burnishing per se. As others have stated...you may have left them too long. AND...if I may add one more thing...not necessary to do both soaps at the same time. I would opt for borax only as you don't have to grate it!  Jack mentioned speed. All I can say there is...when I have a VERY heavy tumble going...it rolls slower. Hope you are able to salvage some! |
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 15, 2008 21:53:47 GMT -5
Thanks for the advice, lizard. The labradorite was actually looking pretty good after the polish and before the burnish. It was smooth and fairly shiny. Here is a pair of photos that I took after the polish that shows off the flash on one piece:   Here is a shot of some of the amy from that batch:  All in all, I was pretty happy with it before I went and trashed it all.  While I'm at it, here is one more photo from that batch:  I have enough labradorite rough to run a homogenous load all the way through. I think I'll give that a try and see what happens. No more burnish, I promise! Thanks for all the good advice here. I look forward to posting some photos in a few weeks of the re-do... |
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Post by connrock on Sept 16, 2008 6:54:22 GMT -5
(when I write I sometimes come off as a know-it-all or being "snooty" but I AM NOT ,,,I just don't how how else to write it) You will NEVER get that rough to end up looking good. If you look at it,it is all fractured already as 181lizard eluded to. If you look closely at the rough I used it is almost fracture free. I know it can be a real bummer trying to find good rough as most sellers think that tumbling rough is just scraps and label the good material as cutting rough which costs a lot more. Anything in the quartz family is difficult to polish and have it come out perfect unless it's almost perfect to begin with. We have an over abundance of quartz here in CT but to find a single piece that's worth tumbling is VERY hard to do. I tumbled some quartz I collected in VT and it came out fantastic! Some of the rough,,,,,,    After tumbling,,,,  You may have noticed that I didn't show you any quartz from CT that I tumbled,,,,,That's cuz it's JUNK and I don't do it! I hope I haven't offended you but you have to remember,,,,Junk in,,,,,Junk out!!! I learned a LOT from a master jeweler,carver,gem cutter,rock tumbler named Rick Stinson,, Here is a write-up of his on rock tumbling: www.gemservice.com/lapidary.htmThis is Rick's Home page,,,,take a look around,,,, www.gemservice.com/Just looking at Rick's work inspired me to go further on in lapidary and it may do the same for you.All it takes is a lot of time and effort,,,,,and it's fun too!! Good Luck,,,,, connrock |
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181lizard
Cave Dweller
Still lurking :)
Member since December 2005
Posts: 2,171
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Post by 181lizard on Sept 16, 2008 11:56:53 GMT -5
Yup Yup! The amy rough looks...well...just that...a little rough LOL! But your Lab pics is pretty nice!!
Connrock...I don't think you're snooty!!! I just think you're right!
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Post by cina on Sept 16, 2008 12:06:33 GMT -5
Amethyst I do ok with I run it alone and get my stock from RS in SD. Labradorite on the other hand has been a thorn in my side from my first bath to the one I have running today I can not get it to look good no matter what I do. I wish you all the best with All your rocks, Steph |
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 16, 2008 18:46:12 GMT -5
Conrock: no offense taken! I promise never to be offended by friendly advice. I suppose one needs to consider the final goal of the tumble. If my final goal were to produce the best possible tumbled amethyst, then I agree that the material shown is largely inadequate and requires significant culling/cutting. But, in fact, my goal is to provide some tumbled amethyst that will please my mother-in-law. She likes the rocks to feel smooth in her hand and to be pretty to look at. She would like a bowl of amethyst to put in her living room. I am sure that I can make her happy using the rough that I have. See what I mean? Not everyone has the same goal in mind when they tumble. That being said, I always appreciate advice on how to get a better end product. That is, after all, why I post/read this forum every day! Right now, I have four barrels of rough that I can divide into two categories. Two of the barrels contain sub-optimal material (one amethyst and one quartz/citrine) that are being tumbled as holiday gifts for my mother-in-law. These will come out nice and make her happy but will never be super shiny or win any awards. The other two barrels contain higher quality material (once ocean jasper and one pet wood + dessert japser) that have the potential to produce top-quality results. I really hope to kick ass on those batches. I guess what I am saying is: I have different standards for different batches. |
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fanatic
starting to spend too much on rocks
Member since October 2007
Posts: 233
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Post by fanatic on Sept 18, 2008 6:31:40 GMT -5
I have achieved mirror finishes on citrine, amys, banded amys, smoky, white, and clear quartz all tumbled together. I just sort out the ones with the chips and toss them back in another batch until they are 'chipless'. Polishing takes at least 14 days and a butt load of pellets to get the mirror finish.
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Sept 18, 2008 10:03:23 GMT -5
Fanatic: can you define "butt load"? How many TBs of pellets in the barrel? Or what is the ratio of pellets to rocks? Thanks! |
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While I'm at it, here is one more photo from that batch:
