stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Sept 28, 2014 10:33:29 GMT -5
Can one of the masters please post a formula for amber that works. Your help is really appreciated! I plan to start corn cob media + 1000 grit pre-polish DRY. Then onto DRY polish. If no results, I plan to back up to 500F DRY. Since amber has no weight, I like some of the ideas I have read by using bungee cords/ tie-downs around the sealed vibe to slow the VPM from 3000- 1000 or so, and to make up for the lost weight. Dry polish was chosen, since I get excellent results with this on soft stones polish stage, and I wouldn't think ceramic media and amber will get along too well in a traditional wet slurry. If this route was necessary (ie, wet 500F stage), I would add some detergent to help slow things down and the microbubbles to cushion and "float" the load. I have had greater success using a little detergent with the grit in the later stages for Soft Stones. Finally, i plan to ensure 75% of the load is media, to reduce collisions, and attempt to get this amber shiny nice. Before tumbling: For those interested, I will be first be using Madagascar copal. I will be placing it in an autoclave with nitrogen gas. I will raise the temperature to 180 degrees celsius (boiling point for copal), in a 17 bar pressure environment (the pressure will prevent the copal from liquefying) . Hold the copal here for 24 hours. Repeat after slowing reducing temperature and pressure. Now the copal "should" be heat-treated amber. I'm doing the treatment, since Madagascar copal is unstable, and very brittle. This is the same process that turns Mexican copal to GREEN AMBER. The [2] Madagascar samples done in the study turned more yellow, not green, but at least "became" amber. The treatment is essentially undetectable, and actually ages the polymerization process that turns young organic copal to fully fossilized amber. End product is legally identified as Amber (Heat-Treated). Process is outlined here in an industry-wide GIA-sponsored report done in 2009: Amber Studythanks in advance, robert
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,759
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Post by gemfeller on Sept 28, 2014 11:30:09 GMT -5
That's fascinating -- thanks for the link. I have that issue of G & G but must have skipped the article. I have no suggestions for tumbling amber but dry methods seem indicated for several reasons, especially since the material floats in water. Keep us up to date on your progress, starting with the autoclave results.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Sept 29, 2014 1:05:33 GMT -5
thanks for your comments. I will share the results.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Sept 30, 2014 11:28:54 GMT -5
It turns out our autoclave only can go up to 1.7 bars of pressure, and we need 17 bars . I have contacted a manufacture in China that is happy to do the tests. Also, i contacted a lab in Tucson to see if they can do the test as well. In the meantime, I will start tumbling our copal. Nobody has a recipe that works? robert
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Post by Toad on Sept 30, 2014 21:39:29 GMT -5
Never tried it, but would be fascinated to learn what works for you.
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Post by connrock on Oct 1, 2014 7:47:03 GMT -5
Copal/amber is a lot softer then Petosky Stones but the only recipe I have for softer materials is for Petosky Stones. It may at least give you some ideas,,,,,
How to tumble Petosky Stones
Step 1: Start with 320 or 500 & finer silicon carbide grit, using a thickening or suspending agent like syrup, sugar, or molasses for cushioning.
Step 2: Use 600 or 800 & finer silicon carbide grit with a ratio of 1 to 1 or 2 to 1 of media to Petoskey stones. Use plastic pellets or coarse-ground walnut shell for media. You may also need to use a thickening agent like syrup, molasses, or sugar (being careful not to thicken load excessively).
If you use 600 silicon carbide grit, follow with 600 aluminum oxide as a pre-polish, jumping to the final polishing stage.
Final Step: Use cerium oxide or 0.5 to 0.8 micron aluminum oxide polish, cushioning with fine-ground walnut shell and a thickening agent like syrup, molasses, or sugar, but do not thicken load excessively. connrock
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Oct 1, 2014 12:09:25 GMT -5
thanks for your suggestions connrock. I like the thickening agent for cushioning. I was using detergent only. I have read others are successful with sugar, but was turned away by the potential mess. I would also wonder try corn starch. I will add this to my soft stone formulas to try. robert
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 9, 2014 11:51:05 GMT -5
I wanted to post an update. re: the transformation from copal to amber. We still do not have the proper autoclave. However, we did use ours (1.7 bars versus 17). The copal melted and reformed into the molds it was in. (we forgot to enclose in sand). The outer surface was slightly burned. The good news is the new version is resistant to acetone ! This means it would test positive for amber. I will take samples to one of our local university labs, or commercial labs and have them do this test properly. re: tumbling copal. My first batch went better than I thought. However i couldn't get it too polish/ I was using wet 120/220, dry 500, dry 1000, dry polish. I started with dry 1000 for 12 hours. Everything under control. worked well, but no shaping. Dropped to dry 5F, same as before. went to wet 60/90 12 hours. Material finally started shaping. In the end the polish had swirls, and i accidentally left a small chard of apatite in the dry polish. Polish was bad, material needs to be reworked. I spent only a few days with this. Next i will use a thickening agent (like connock suggested), but will opt for corn starch.
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Post by connrock on Nov 10, 2014 9:15:04 GMT -5
I use Lot-O-Tumblers for everything after the roughing and something I always do is add powdered Dreft laundry detergent before adding grit/polish. With rocks that are perfectly smooth with no flaws whatsoever I add only about 1 tablespoon of the soap but with rocks that have "flaws" I add a lot more ,,,,maybe 3-4 tablespoons of soap. Defining flaws: Some rocks(especially some agates)have beautiful "patterns" that are only on the surface of the rocks and if you grind them smooth you loose the beautiful colors and patterns.Some petrified wood is pitted and Montana Agate has VERY tiny cracks throughout which can and will hold grit/polish.These are only a few examples.
My theory in adding a lot of soap before adding grit/polish is that the soap gets into the flaws before the grit/polish has a chance to and even if the grit/polish does get into the flaws it mixes with the soap which makes for a much easier clean-out.I HATE rocks that show polish in the flaws and so far this method has eliminated this for me.
Why am I telling you this? While trying different amounts of soap I had to determining how much was enough and how much was too much. When I found out how much was too much,I had a very thick "soap slurry" and started thinking about what a great thickener this could be.No sugar,no corn starch,,,no nothin but pure soap that would be very easy to clean up!
I don't know if a thick soap slurry will help with your amber but it may be worth a try?
Good luck and please keep us posted. connrock
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 10, 2014 10:16:15 GMT -5
Thanks connrock for another good suggestion. I will add that idea on the list of thickeners to try. My concern with this method is the environment with all the soap over time (if you need a lot).
I like your method for filling the gaps in alluvial agate. Your concept is quite unique. People leave these in the grind till the pits are ground out. As you point out colors can disappear in millimeters (desert jasper / aka polychrome jasper) on the surfaces, and some don't need PERFECT baroque shape - yet some pits can be too deep so either you: a) don't select them in the first place, or b) waste a lot of energy making them perfect, or c) fill the gaps to avoid contamination. What easier than when your adding (powdered soap) in the first place, before the grit gets in. Thanks again.
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Post by connrock on Nov 11, 2014 7:42:35 GMT -5
I don't normally tumble rocks that are pitted throughout or are very fractured but there is the occasional exception when I'm doing some petrified woods. I used to do a lot of trading with people who lived in the west because there isn't much to be had in the northeast where I live.Many times I would receive "inferior" rocks in my trades but it's what I had so I dealt with it. This piece of petrified wood is common to what I got and as you can see it's quite pitted.The white and light gray areas yo see are NOT polish or grit.They are part of the rocks composition. You can see that the actual pits don't have any polish or grit in them yet the outer surface is highly polished. Some Arizona petrified wood is beautiful with multiple colors but it looks like Corn Flakes all glued together and usually isn't a very good tumbling material. This is a piece of Arizona petrified wood about 2-1/4" x 2-1/4" and varies in thickness. This is a close-up on one of the problem areas and again,you don't see any polish or grit in the"flaws"! These pieces are typical of what I've done using a thick soap "slurry". I know that,in your case, using a lot of soap wouldn't be an option unless you could find a soap that is biodegradable,if in fact you could use a thick soap slurry for any of your tumbling needs. connrock
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Post by orrum on Nov 11, 2014 9:27:19 GMT -5
I was told to polish Amber by rubbing it on your jeans as you watch TV.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 11, 2014 12:29:16 GMT -5
orrum - Yes, copal can be easily hand-polished with fine sand paper and then polish. low production. high labor. We are trying to get the best method to successfully tumble it.
connrock. thanks again for the details and pics. Amazing that that your system works with all those natural imperfections in the pw. We experience an issue with varying hardness from time to time with our madagascan wood.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 15, 2014 13:50:32 GMT -5
2nd copal attempt started a few days ago. I started 5F wet SiC with extra soap (as per connrocks suggestion) for pit-filling and slowing down the slurry. I wanted even less action, and more thickening, so I added cornstarch. Finally, the slurry is thick and slow. I ran it for 40 hours and the copal was nicely over-done in this round. I left it an extra 20 hours since i was too lazy to drop down to 120/220 where I think I will start next time. Cornstarch makes cleanup harder, and kind of annoying. Sugar wasn't slow enough either. Broken edges are smooth eased-edges now. I primary concerned with polishing of copal, so the shape can be easily adjusted once I learn how to first polish it
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Post by connrock on Nov 16, 2014 11:52:45 GMT -5
I think I remember you saying you are doing the copal in a Lot-O-Tumbler? Another way of slowing down the action comes with the instructions with the L-O-T for doing obsidian. Add water to cover the rocks.This slows things down quite a bit and also makes the barrel "compress" down into the frame. Dunno if this will help with copal and I totally forgot about it before. What polish will you use for the copal? connrock
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Nov 17, 2014 0:03:31 GMT -5
Thanks connrock for your idea. I'm using a UV-10. Do you think the water idea will work in a UV-10? I will likely modify my toy to get the counter-weight on the motor another 50% towards true. This will bring the VPM to 1500 (slow it down 50%). It would be nice if I can switch between fast and slow.. or just dedicate a unit for slow speed. I know variable speed motors don't last long.
I was planning to use Al Oxide polish, but have cerium available to try. I believe have pin-pointed AL oxide 1000 is where my trouble starts. So my 2nd attempt at polishing copal failed during the pre-polish wet 1000 Al Oxide. The longer in there, the worse it got.
These are in some cases deep long straight scratches (upto 2mm) deep, or flowing circular fingerprints. I left the copal go for 24 hours (extra Dreft soap 3TB) and 2 TB of corn starch for thickening. I let the slurry go real slow which might have made it worse too. However, my first run was 8 hours dry 1000 Al Oxide, and the fingerprints were about 50% less.
Despite the bad results, finishing the copal with some wax actually made it "appear" ok and in saleable condition. Considering copal must be stabilized at the very least, temporarily, with mineral oil at the end. The Ed.Smith tumbling book just arrived, "how to polish rocks into gems..." mentions with very soft rocks (amber); the prepolish and polish stages is where the finish can get worse. I need to read that part for any further insights.
First, I thought it was the ceramic, then contamination, maybe Al Oxide - since it was perfect in 500 SiC, or the Dreft soap perhaps etching the copal...
thanks
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Post by connrock on Nov 17, 2014 8:18:02 GMT -5
I don't think using ceramic media is a good idea as it's harder then the copal and it will scratch it no matter how thick the slurry is.
I'm not sure if covering rocks(copal) with water in a UV-10 will work as I've never run one but others may have in-put on this. Good luck,,, connrock
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 15, 2015 22:33:55 GMT -5
Cannot let this topic die:) Here are some updates. First off, copal has varying hardness making it much more difficult than copal treated amber/ or amber. update on the autoclave: I learned that the amber industry is in Gdansk, Poland. In Gdansk, it is common to a) treat the copal in an autoclave to transform it into amber, including green amber. b) tumble amber. I'm working with a company in Poland that makes the autoclaves for the amber market. They will be testing our samples before I purchase the unit. Again, once treated to amber, the copal-amber is much harder, uniform hardness (no gummy soft parts), so much easier to tumble. Next, after having at least 7 mediocre results (using vibe and ceramic media / and dry method 1000 and polish stages with corn cob , I was suspicious of the ceramic media being part of the problem, as connrock suggested. I'm sure that is true in the early stage (500 or 120, with 120 being overkill). However damage still occurred in the corn cob. Both methods, even at 1000 produced "fingerprint" problems. So, the biggest game-changer, was learning the vibratory method of tumbling was the ultimate problem. I found from some help of a mass-finishing company, Kramer industries, on how they tumble plastic. One secret is using hardwood shapes (cubes or pegs) that you treated with an abrasive compound. The hardwood absorbs the paste and then it asks as both media and carrier to the amber. The other secret, and I'm sure captbob would love to hear this, is you need to do this in a rotary to get the best results!I've recently learned this, and gotten great results so far. Keep in mind while waiting for the compounds and hardwood media to arrive, I have improvised with wooden pellets from Petco, and created my own abrasive compounds. (BTW you can get cheap corn cob, and walnut shell at PetCo as well). So the wooden cube hardwood media make up for the weight issue of the very light copal, and protect it the rotary via a gentle tumble. This is how they polish the machine marks off buttons for clothes for example. So the basic recipe is using each of the 3 steps of the compounds in the treated media (and reusing them as needed) for 12-24 hours per cycle. A dry process. grinding being 500 grit Al Oxide, pre-polish being 1000 grit Al Oxide, and polish being 1500 grit ( as per Kramer industries technician). I can foresee using a much finer polish step, in addition to the 3 mentioned. I will post pictures once I'm satisfied with all the steps, and have the time. ***this technique will be perfect for stones that "don't tumble" with Moh's < 3 ! Here is simple instructions I found how they tumble amber in Gdansk. I cannot give anyone credit since the same instructions are posted on many sites, but this is not my method, but should be included in this thread. Interesting how this method is quite similar to what I learned (rotary, hardwood shapes, polishing compound, and dry polish). "First tumbling is done with sand and water in order to remove hard skin of amber. The barrel must be made of metal because the sand is strong abrasive. Next stage is tumbling with soap water and pumice, if you will use the same barrel please wash it carefully, because single piece of sand may spoil all the amber polishing. After spinning around 12 hours the amber material will look nearly finished. The last touch is tumbling in the dry barrel. The barrel must be hexagonal and made of wood or other soft material such as plastic. The amber must "breath" when is being tumbled, so net of small holes is drilled for this purpose. The media of small wooden cubes and special natural paste is used. I do not know where to buy this paste in England. I have brought some from Gdansk - the capital of amber. After overnight tumbling in the dry barrel the amber pieces are really shiny" So the traditional method uses sand rather than Al oxide. There must be some media used, not mentioned (hardwood shapes). Pumice is like 1000 grit AL oxide, and tripoli is like 2000 grit (will polish amber) for old-timers , and will work.
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Shelbeeray
has rocks in the head
Member since January 2006
Posts: 688
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Post by Shelbeeray on Aug 17, 2015 19:43:58 GMT -5
Connrock, which soap do you use?
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