suema
off to a rocking start
Member since December 2017
Posts: 3
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Post by suema on Dec 1, 2017 5:16:32 GMT -5
Hi .I have just pre polished already rounded and smooth ish Tasmanian Jasper collected from the beach.we done coarse grit medium grit and pre polish (this is our first time) instructions say that we should get a shine on them if we put some polish on a fat and rub we did this but no shine yet but they feel very glassy.. should we move to the next stage polish?any advice would be appreciated.cheers sue
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Tommy
Administrator
Member since January 2013
Posts: 12,897
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Post by Tommy on Dec 1, 2017 11:28:59 GMT -5
Hi suema welcome to the forum. I'm going to move your post into the Rock Tumbling category because I think it will get a lot more good answers there.
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Post by MsAli on Dec 1, 2017 11:30:46 GMT -5
Welcome from Cali-pictures please
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Post by gmitch067 on Dec 1, 2017 15:34:45 GMT -5
Welcome to the Forum suema from Northern California! It sounds like you are tumbling some nice jasper... from what you said, you have already run them through 3 of the 4 basic steps of tumbling and now have stones that are nicely shaped and smooth. Sounds good so far. Well done. Now all you need to do is polish them. Before I can advise you further, I need to know something about your equipment... What type of tumbler are you running? (...or... are you polishing these stones by hand with sandpapers?) How many pounds (or kg) of rock is it capable of tumbling? Glenn
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Post by pauls on Dec 1, 2017 15:46:24 GMT -5
Hi suema I agree, we need a few more details before we can help. I'm not even sure what you mean by "putting some polish on a fat and rub" What is it you are doing, with what are you doing it, and if its a tumbler, what sort and for how long?
The people here are really good at helping, we just need to know the ins and outs of your problem first.
Paul
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Post by rmf on Dec 1, 2017 18:09:21 GMT -5
suema,
I have never been a big fan of (Coarse grit, Medium grit and prepolish) Now used by Lortone and others. I am too picky, I like to know what grit size I am using and then I can adjust my recipe as necessary. So what follows may not answer your question.
I usually like to tumble in a coarse grit of 46-70 silicon Carbide. This is a split and it gives me the best bang for the buck in my tumbling (usually agates and jaspers). Coarse can be anywhere from 30 grit to 120 grit depending what is available to you and the type of stones you have (some are more rounded than others -- well rounded stones like beach stones may be rounded enough they can be started in Medium grit.
Medium grit that I use is normally a split from 180 to 240. Again the split is used because it is cheaper.
Pre-polish is what i call fine grit. This is either 400 and finer or 600 and finer both are splits it just depends on what I can get.
the recipe for tumbling is not an exact thing like making a cake from scratch. If you use a different size grit you may need to adjust with longer run times there and it also depends on the type of drum & type and condition of the rock. I know of a commercial rock tumbler that used 600 -1200 pound drums made of steal pipe. they use only one grit 46-70 coarce. He tumbles his rocks for a month the runs them through polish. the coarse breaks down to finer and finer grit as he tumbles and he needs no fine/pre-polish. With rubber drums in the 3-12 pound range it is more efficient to change out the grits.
For 3 pound tumblers is is ok to tumble agate, jasper, quartz, quartzites and aventurines together polishing will do fine. As your tumbling drum diameter increases to the 6# and 12# and larger drums you need to separate the less tough quartz, quartzites and aventurines and do them together. they are the same hardness but not the same toughness. Think of Agate as woven fibers like a bed sheet as opposed to a single fiber. the fibers in agate help transmit the force of the rocks hitting each other in the tumbler to other parts in a stone. If you see frosting around the corners of the stone but aa good polish otherwise this is the reason most likely.
In a rotary tumbler if it has tumbled for a week in fine then it is ready to go to polish. It will take at least 3 to 4 days in polish to begin to see a polish started. It is not worth my time to test a piece. I take the results of a batch and correct/redo as necessary. it is good to have a good mix of small to large maybe even up to 25% small. these really help the polish process.
Never run your tumbler in polish les than 80% full (reuse small stuff if necessary) Running a tumbler half full ruins the polish. the Lortone tumbler book shows a tumbler half full and they are just showing how it works they are not suggesting to run 50% full. Many people just run one batch start to finish. Usually you grind up about 30% of the rock in tumbling and it goes out as mud. This should be filled with other rock. (never use fillers except for cushioning in polish) it is too much work (at least for me).
If you use softer rocks with harder rocks like agate and sodalite, your sodalite may not polish.
Do you know what type of rocks you picked up? If tumbled for a week in fine (assumes rotary tumbler) then go to polish. If it does not polish the it may be too soft, may need more 1/4" pebbles in the fine or some cushioning in the polish (plastic pellets, wood pieces, carpet...)
Good luck!
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suema
off to a rocking start
Member since December 2017
Posts: 3
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Post by suema on Dec 1, 2017 21:53:50 GMT -5
Thank you all for your replies, I use a Lortone 3lb tumbler.I was just a little concerned that the stones after the third stage of tumbling were very smooth but had no shine. According to the book I got with the tumbler the stone should have a slight shine at this stage,before proceeding to final polish stage.
My question then is,should I have tumbled the rock more in stage 3 before final polish stage?
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Post by gmitch067 on Dec 2, 2017 7:57:19 GMT -5
Good tumbler to start out on suema . I would progress to the polish stage. I do not use the Lortone recommended quantities of grit. I think them a bit over-kill. I have cut back quite a bit and only use 3 tablespoons (TBS) per load (all stages… the same). It works for me. Most of the shaping of the stone will take place in the first stage - coarse grit (I think Lortone uses 60/90 grit). The grit breaks down during tumbling stages. I do my stage-1 tumble for 7-days, clean and inspect the stones, and then recharge the grit (replace it with fresh grit). With hard stones like jaspers or agates a 7-day tumble is not enough to get the shape pleasing and free of blemish. It is not uncommon to run and re-run stage-1 3-4 times (or more!). The 60/90 grit leaves scratches on the surface of the stone that are noticeable with a magnifying glass. Stage-2 uses a finer grit abrasive (I think Lortone uses something like 220 grit). It serves to remove the scratches of the previous stage. The scratches are harder to see at the end of a stage-2 tumble… but if there are still scratches left over from Stage-1 you will be able to see the difference. If you notice rough patches under the magnifying glass (dry a rock or two before checking), re-run the 220 grit stage. Stage-3 uses something like 600 grit. I usually only run this stage once. I can not see or feel any change to smoothness from the 220 grit scratches… too fine for my old eyes or weathered hands to tell. If the jasper stone is on the hard side of the scale (Mohs 6.5-7) – or the stone is an agate – you might see a slight sheen after a week long run. Proceed to the Stage-4 Polish stage… even though you do not see the beginnings of a polish in the sheen. Stage-4 grit is something like 14,000 grit(!!!). After a week in the tumbler, the jasper begins to smile and glow for you! Have fun! Glenn
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Post by rmf on Dec 2, 2017 7:59:32 GMT -5
suema,
The short answer is if you tumbled it for a week in fine then you are good to go. the long answer is that your mileage may vary because some rocks are just different or have spots in them that require special handling. the Lortone book (we have been Lortone dealers for years) is good it provides a great starter tumbling recipe but when God put things together He sometimes mixed the rocks just a tad different than normal. I am not familiar with the Jasper you are tumbling but for normal Jaspers the default Lortone recipe should/does work great.
Included below are some tips we give our customers when they purchase a tumbler that are not covered in the book (adequately) IMHO.
1. Be sure the rim on the inside of the barrel (Lortone tumbler barrel) is cleaned each time the barrel in opened and checked. 2. Place a small stone (about the size of a barrel nut) under the bottom of the barrel and push down while you install the lid. This creates a dimple in the barrel bottom which will pop out if the barrel builds up pressure. If pressure is too great, it can pop the lid and dump mud and grit all over. Gas (carbon dioxide, what we exhale) is produced by stones such as obsidian and glass during tumbling. 3. Be sure to place the tumbler where it won't matter if the lid pops off. This does not happen often if the tumbler lid is installed correctly but occasionally gas builds up due to the material and the heat created from the friction of tumbling. A dish pan is about the right size to hold a Lortone 3A tumbler. Does not happen often but does happen and it is messy. 4. After you finish tumbling your stones in coarse grit, any grit that has not been broken down can be recovered and reused. Just wash the stones over a bucket and the coarse grit will settle to the bottom (a 5 gallon bucket works best). Pour off the water and silt and keep the remaining coarse grit to use in the next batch. It can be added to reduce the amount of fresh grit. It is possible to recover some of the medium grit (120/220) but it is not usually worth the trouble for a 3A tumbler. Below 220 grit the grit is too fine to recover. 5. DO NOT wash the tumbler barrel out over the sink. The silt will set up like concrete in the trap. 6. Use a pinch of soap (powder or liquid) in the 400, 600 mesh grit and also with the polish. This breaks the surface tension of the water and helps the grit get suspended in the water so it can cut in all directions. Without the soap, the grit acts like lumpy gravy. 7. When you are ready to go to the next grit after cleaning the stones, put them back in the tumbler drum and run them in some really soapy water for 5 to 10 minutes. This cleans the barrel and the stones before going to the next grit. This assumes you are using one barrel for all grits and polish. This is especially important just before starting the polish cycle. 8. When the stones are finished polishing, DO NOT DUMP THE POLISH OUT. Get a one gallon jug with a lid. Pour the polish into the jug and save it. Rinse the rocks until the water is clear, each time saving the polish in the gallon jug. Set the jug on the shelf for a week or two and then after the polish settles out pour off the clear water. Do this several times until there is a thin layer of water over the polish. The next time you are ready to polish stones you may want to add a little extra polish but you should be able to dump the polish solution into the drum and start polishing. As long as the polish stays clean, it can be used indefinitely. 9. To get a good polish make sure there is a mixture of sizes from big to small. If you need more small rocks try re-tumbling some from a previous batch and adding them to the batch that does not have the right amount of small rocks. For best results have about 20% - ¼ --½ inch. The book that comes with the Lortone tumbler makes it look as though you can polish rocks with a half full tumbler. This is not the case. The tumbler should be three-quarters full at all times to get the best results. This can be achieved in several ways: 1. Run two batches in the coarse grit (46-70grit coarse) and then when you go to the next step (120-220grit medium) you take from the second batch you finished in coarse and use about half of it to fill the tumbler back up to three-quarters full. 2. You can use some smaller stones of the same hardness to act as filler. (Many people use the small stones for doing Gem Trees or glue on braclets.) 3. Lortone's book says use plastic pellets. Keep in mind if you use plastic pellets, you must have a separate set for each grit stage and polish. This is because grit will get stuck in the plastic and spoil the finish of the rock. I recommend using plastic pellets only for the polish cycle, only for “hard to polish” rocks like obsidian, and other stones listed in group 6 below.
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Post by gmitch067 on Dec 2, 2017 8:08:13 GMT -5
Very nice write-up rmf. Good recommendations+++ Glenn
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suema
off to a rocking start
Member since December 2017
Posts: 3
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Post by suema on Dec 2, 2017 22:46:54 GMT -5
Thank you for the informative replies. I will let you all know how it turns out.
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Post by Pat on Dec 3, 2017 0:50:40 GMT -5
I don't know anything about tumbling, but welcome!
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