jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Aug 2, 2020 8:15:37 GMT -5
These 3 pieces of glass show 3 situations caused by using large silicon carbide and the folly of skipping/shortening the steps to polish. I skipped the entire 2 day SiC 500 vibe run on the blue glass. The AO 220 vibe run did not come close to removing the pits from the large SiC. The yellow pitted piece was pulled after 1 day of the 2 day SiC 500 run in the vibe. Pits not as deep but still a big problem. AO 220 could not remove the pits. The polished piece still shows a few scratches from the large SiC because the 2 day SiC 60 run was skipped in the rotary. The 'SiC 60' is actually screened from the raw SiC with a 60 mesh screen so it is 60 and smaller. These tests determine the minimum run time for each step accurately.
|
|
dkurtz
having dreams about rocks
Tumbling to de-stress from my work. :)
Member since February 2010
Posts: 66
|
Post by dkurtz on Aug 2, 2020 12:14:35 GMT -5
It really shows why you need to do all steps. Thanks.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Aug 2, 2020 12:26:41 GMT -5
It really shows why you need to do all steps. Thanks. I have tried many combinations of abrasives over the years dkurtz. It is easy to pull a couple of samples for s step to see what happens after final polish. Basic and easy to do to know a lot about what is actually happening.
|
|
braat
spending too much on rocks
Member since December 2016
Posts: 350
|
Post by braat on Aug 2, 2020 12:35:30 GMT -5
I get minor glass pitting quite often and am still unsure which stage is causing (not removing) the pitting... I interpret your post as saying stage1/rough is where pitting should be removed?
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Aug 2, 2020 15:51:54 GMT -5
I get minor glass pitting quite often and am still unsure which stage is causing (not removing) the pitting... I interpret your post as saying stage1/rough is where pitting should be removed? A lot of the pits I find in glass is bubbles. It is hard to tell them apart from these large abrasive pits. I had tumbled a lot of this glass in the past and had no pits so the pits I have this go around is from the coarse step 1 abrasives no doubt. Super coarse abrasive = fast shaping but comes with deeper pits and requires another finer step '1'. Especially glass.
|
|
braat
spending too much on rocks
Member since December 2016
Posts: 350
|
Post by braat on Aug 2, 2020 17:28:11 GMT -5
I get minor glass pitting quite often and am still unsure which stage is causing (not removing) the pitting... I interpret your post as saying stage1/rough is where pitting should be removed? A lot of the pits I find in glass is bubbles. It is hard to tell them apart from these large abrasive pits. I had tumbled a lot of this glass in the past and had no pits so the pits I have this go around is from the coarse step 1 abrasives no doubt. Super coarse abrasive = fast shaping but comes with deeper pits and requires another finer step '1'. Especially glass. Thanks...never really considered bubbles...I guess in future I'll pay closer attention to the condition of what I throw in the rough stage...
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Aug 2, 2020 17:45:58 GMT -5
Decorative and hand blown glass is more likely to have bubbles. Machine made is least likely to have bubbles braat. Machine blown vases can be some of the finest glass to tumble. It is hard, bubble/defect free, and has some insane and complicated designs perfectly brewed into the end product. And you don't have to worry about breaking some fine and famous artists's high art into pieces. I have seen many a $500 to $1000 vase in a thrift shop for $10.
|
|
|
Post by Bob on Sept 2, 2020 23:08:20 GMT -5
Glass and obsidian is weird. I am tumbling a lot of it now. You will learn a whole lot after each stage by inspecting surfaces with 1Ox lens after totally dry. Be prepared for some surprises.
Even though glass and obsidian have lower Mohs than quartz, I have had good luck tumbling them with my delicate crystal quartzs like amethyst, rose, smokey, etc. Though I am currently all in 600 and 1,000.
I was warned by very experienced tumbler to have minimum 3 yrs experience before doing glass and obsidian. I tried it then and had big problems in polish. Now 3 more years and am trying again.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Sept 3, 2020 6:46:57 GMT -5
Glass and obsidian is weird. I am tumbling a lot of it now. You will learn a whole lot after each stage by inspecting surfaces with 1Ox lens after totally dry. Be prepared for some surprises. Even though glass and obsidian have lower Mohs than quartz, I have had good luck tumbling them with my delicate crystal quartzs like amethyst, rose, smokey, etc. Though I am currently all in 600 and 1,000. I was warned by very experienced tumbler to have minimum 3 yrs experience before doing glass and obsidian. I tried it then and had big problems in polish. Now 3 more years and am trying again. You mentioned jade in another thread of yours. Jade defies a tumble polish, something about it's structure. Felspar too, it has different Mohs depending on cleavage face. Glass and obsidian are a joke to polish if the vibe is set up correctly mechanically. After years of tinkering with polishing obsidian I discovered the vibe was the culprit. Vibes NOT created equal. Glass/obsidian are of a totally homogenous structure unlike jade, felspar, crystalline quartz, fluorite, etc. A quick tumble if your vibe is mechanically tuned for it and applied slurries are appropriate. The trick with it is to never bruise it from start to finish. Best if tumbled in a batch where no piece of glass is heavier than 20 grams to avoid higher mechanical impact forces. I have used this 11 to 12 day recipe for glass well over 100 batches practically blindfolded. Be aware the vibe is modified in a way it is difficult to damage a load of glass. And slurry is used, this is critical. 5 days coarse SiC 30(or coarser) in a clay slurry at 74 rpm rotary. 2 days in SiC 500 with sugar in vibe 3 days with AO 220 with sugar in vibe Anywhere for *3 hours to 18 hours in AO 14,000 with sugar in vibe. *If left in the AO 220 for 4 days the AO 14,000 will deliver a fine polish in 3 hours. The near-polish achieved from AO 220 after 4 days is similar to many many folks achieving a wet polish in a Lot-O using AO 500. Proffesional glass artists prefer cerium oxide to polish glass when using their lap.
|
|
|
Post by Bob on Sept 3, 2020 8:09:38 GMT -5
I only do rotary, not vibratory. Some of the pieces are larger than a lemon, especially the mahogany ob. Last time did polish run, combined ob and glass. Not going to do that this time.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Sept 4, 2020 8:31:33 GMT -5
I only do rotary, not vibratory. Some of the pieces are larger than a lemon, especially the mahogany ob. Last time did polish run, combined ob and glass. Not going to do that this time. Never succeeded polishing a piece of glass the size of a lemon. Should be doable if the lemon sized chunk was alone, rolling or vibrating in 100% pea gravel or ceramics. Rolling 2 big rocks together in one barrel is an invitation for bruises. They will hit each other constantly and most likely damage each other. The damage may be slight, perhaps only a matte finish instead of a wet polish. Or a total frosting. If I tumble shape and polish big rocks I put one big rock per smallest possible barrel, and I have 5 small barrels to run 5 big rocks at a time separately in 100% smalls. Big rock = 1 pound or larger. But a 1/2 pound big rock running with a 1 pound big rock is a recipe for a bad ending unless rolling very slow with thick slurry. So slow the tumble takes a long time. Much faster to do a single big rock surrounded by 100% 1 to 1.5 inch agates rolling at higher rpm. Done dozens this way. www.flickr.com/photos/67205364@N06/sets/72157662746031090Big rock polish 1 pound in rotary with 100% smalls, hard snake skin agate Big rock polish 1.5 pounds in vibe with 100% smalls, hard rockpickerforever agate and used only coarse AO 22 from pre-polish to end polish !
|
|
|
Post by HankRocks on Sept 4, 2020 10:36:51 GMT -5
I only do rotary, not vibratory. Some of the pieces are larger than a lemon, especially the mahogany ob. Last time did polish run, combined ob and glass. Not going to do that this time. Never succeeded polishing a piece of glass the size of a lemon. Should be doable if the lemon sized chunk was alone, rolling or vibrating in 100% pea gravel or ceramics. Rolling 2 big rocks together in one barrel is an invitation for bruises. They will hit each other constantly and most likely damage each other. The damage may be slight, perhaps only a matte finish instead of a wet polish. Or a total frosting. If I tumble shape and polish big rocks I put one big rock per smallest possible barrel, and I have 5 small barrels to run 5 big rocks at a time separately in 100% smalls. Big rock = 1 pound or larger. But a 1/2 pound big rock running with a 1 pound big rock is a recipe for a bad ending unless rolling very slow with thick slurry. So slow the tumble takes a long time. Much faster to do a single big rock surrounded by 100% 1 to 1.5 inch agates rolling at higher rpm. Done dozens this way. www.flickr.com/photos/67205364@N06/sets/72157662746031090So, To tumble and polish multiple Bigs in the same barrel without bruising. The "Gauntlet has been thrown", the quest for the Grail !!! Who will be our Galahad? Scenes from Monty Python always pop in my head when I hear or say Grail! Think I will just "silly walk" back out to the garage to continue my chores.
|
|
|
Post by Bob on Sept 4, 2020 10:45:52 GMT -5
Perhaps I will show my pile of glass and obsidian before I head into polish which should be before the end of the year. I think there will be almost 20lbs total. Since larger pieces are what interests me the most in tumbling, if that can't be done well with glass/ob, I will probably stop working with it. I am saving my largest pieces of ob to see what happens this fall. I have two cantaloupe size pieces that are too large for my 12lb barrels and will have to go all the way to polish in the 20lb barrel. These two large pieces are mahog ob.
Because I have a tablesaw and lots of sawdust, I have experimented this year with adding a bit to slurries to thicken them. It seems to help. By the time a week has run, the sawdust is all gone. I have not tried this with finer than 600 yet though. It this worked with polish it might be something to try with delicate stuff, though I would expect it would alter the polish forever and I would need to keep that used polish separate from normal used polish.
As a former cabinetmaker, I realize that sawdust ins't just sawdust, so there are risks. Just one piece of lumber stored for instance in a gravel parking lot on a dirty concrete floor can embed grit into the wood and there are many more potential contaminants including pieces of silicon carbide saw blade teeth! So I have thought about sawing up pure soft production pine boards too to try this with later stages and polish to increase the likelihood that the sawdust is pure sawdust. So far I've not ever added but maybe 1/4 cup to a 20lb barrel--which isn't much.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Sept 4, 2020 16:43:17 GMT -5
Sugar makes a durable slurry because it has no particulates that can break down over time. Like SAE 30 weight motor oil in an engine it is a fluid. It maintains constant viscosity at the almost constant temperature of a tumbler to protect your stuff. However a tumbler running in a hot location may require a heavier dose of sugar dissolved because the heat lowers the viscosity.
Clay has particles that do break down a bit but it takes a long time. Rate depends on type of clay. It makes a great starting slurry for step 1, the rocks will add to it as they grind making it thicker. No where to go but thicker with more protection.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Sept 4, 2020 16:53:38 GMT -5
Never succeeded polishing a piece of glass the size of a lemon. Should be doable if the lemon sized chunk was alone, rolling or vibrating in 100% pea gravel or ceramics. Rolling 2 big rocks together in one barrel is an invitation for bruises. They will hit each other constantly and most likely damage each other. The damage may be slight, perhaps only a matte finish instead of a wet polish. Or a total frosting. If I tumble shape and polish big rocks I put one big rock per smallest possible barrel, and I have 5 small barrels to run 5 big rocks at a time separately in 100% smalls. Big rock = 1 pound or larger. But a 1/2 pound big rock running with a 1 pound big rock is a recipe for a bad ending unless rolling very slow with thick slurry. So slow the tumble takes a long time. Much faster to do a single big rock surrounded by 100% 1 to 1.5 inch agates rolling at higher rpm. Done dozens this way. www.flickr.com/photos/67205364@N06/sets/72157662746031090So, To tumble and polish multiple Bigs in the same barrel without bruising. The "Gauntlet has been thrown", the quest for the Grail !!! Who will be our Galahad? Scenes from Monty Python always pop in my head when I hear or say Grail! Think I will just "silly walk" back out to the garage to continue my chores. Let's say I personally was guaranteed to not have frosting or bruising if a single big rock was run with all smalls. Just playing it safe. Mama won't allow bruises ! Not to mention the big rock shaped quickly due to the high rotation speed allowed by running 100% smalls.
|
|
Wooferhound
Cave Dweller
Lortone QT66 and 3A
Member since December 2016
Posts: 1,423
|
Post by Wooferhound on Sept 5, 2020 12:42:51 GMT -5
I like Raw Silicon Carbide much better than Over Cooked
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Sept 5, 2020 18:24:19 GMT -5
I like Raw Silicon Carbide much better than Over Cooked With cheese ! Nothing better than god ole cheese grits.
|
|
lililove12
off to a rocking start
Member since March 2020
Posts: 5
|
Post by lililove12 on Mar 5, 2021 4:58:48 GMT -5
—To tumble and polish multiple Bigs in the same barrel without bruising. The "Gauntlet has been thrown", the quest for the Grail !!! Who will be our Galahad?—
I shall be Guinevere and pick up said gauntlet
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Mar 5, 2021 6:02:19 GMT -5
—To tumble and polish multiple Bigs in the same barrel without bruising. The "Gauntlet has been thrown", the quest for the Grail !!! Who will be our Galahad?— I shall be Guinevere and pick up said gauntlet Ah ! Be aware of Sir Lancealot's polished affections my fair Lady.
|
|