raider30
off to a rocking start
Member since December 2009
Posts: 18
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Post by raider30 on Jan 10, 2010 13:51:55 GMT -5
Greetings again all! I posted a bit before/around Christmas with a bunch of questions and you all came through in spades! Unfortunately it has been so incredibly busy around here - fiance was in and out of the hospital with kidney stones, Christmas, then 6 relatives came from all over the country, we got married on December 31st, and finally halfway back to normal last week. So bottom line I just got my tumbler started today at 12pm. In addition to the thanks to you all for answering my questions a huge thank you, along with public recognition, needs to go to Tony, aka catmandewe. He sent me, free of charge, a box with about 3lbs of rocks, and some little baggies of grit/polish along with a very nice hand written note with detailed instructions and a wish for a great wedding day. What a fantastic thing to do! Now onto the rocks: I filled my bowl with the rocks, and since it wasn't quite 3/4 of the way I added in some plastic pellets(as per instructions Randy posted on his great 'how to use a vibe tumbler' post). I then added in 2 teaspoons of 220 grit(as per Tony's instructions). Which left me wondering how much water exactly to use. I know its better to start slow and then add more if necessary, but, and please correct me if I'm mistaken, a vibe tumbler doesn't need near as much water as a rotary right? So I used a spray bottle and sprayed 10 times. Then I locked everything down tight and plugged it in. What I saw with only the rocks in the bowl was the rocks just sort of moving in a slow circle. However, now that I've added in the pellets, the grit and the water, the rocks are shucking and jiving like crazy. I'll admit I sat there staring in fascination for about 5 minutes, because you'd see a rock floating along the top, suddenly turn and disappear to the bottom like it was caught in a sinkhole, and then pop back up on the other side of the bowl in about 20 seconds.  So far does it sound like I'm doing it right? It's been about 15 minutes and the rocks appear to be moving as I just described above. I stopped it and checked on some of the rocks and they all have a fine little coating of grit(I assume that is a good thing), and there is a certain dampness(feel and smell) to the bowl. Is that how it is supposed to be? So here come the questions: 1) How often do I need to add more grit and if I do need to add more grit do I just toss in another teaspoon full or do I remove everything, clean them all and then start over? 2) How do I know if I have the right amount of water? Is the motion of the rocks a good indicator or is there some other test? 2a) Does water tend to evaporate pretty fast in a vibe tumbler? Meaning will I have to spray it every hour, and if that is the case, what do people do when it is night time and you are supposed to be sleeping? Can I just shut it off over night and start it back up in the morning? 3) With a vibe tumbler will I get a thick foamy slurry like I've seen pictures of with the rotary tumblers? Ok, there are actually a lot more than 3 questions stacked up there, but I know you guys'll be more than helpful! Thanks in advance, - Beau aka Raider30 |
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Post by johnjsgems on Jan 10, 2010 16:21:59 GMT -5
The grit will be broken down by day two so rinse and reload if needed. Recall the fast, initial motion and spray (a spray at a time) to restore that motion. Depends on tumbler how much evaporation. After first step you shouldn't need to monitor as closely. First step I would check every two hours. Leave lid on and it should restart next day with no problem. Fine grit and polish should work ok overnight (unless noise is a problem).
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Post by deb193redux on Jan 10, 2010 16:42:38 GMT -5
You sould have ceramic pellets not plastic. Plastic is only for rotary. They will not exactly hurt in a vibe, but they are entirely useless.
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raider30
off to a rocking start
Member since December 2009
Posts: 18
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Post by raider30 on Jan 10, 2010 19:02:52 GMT -5
You sould have ceramic pellets not plastic. Plastic is only for rotary. They will not exactly hurt in a vibe, but they are entirely useless. Hm..please explain. I had thought that the purpose of pellets was to add additional 'filler' when you had a load that wasn't quite as full as it needed to be for a proper run. They also had the benefit of acting as a grit carrier for the rocks to bump up against. In my case, the rocks weren't quite having proper movement(as described by Randy's instructions) in that they just sort of circled the bowl rather than moving up/down and outside to inside, until I added the pellets in. I guess I'm asking: Did I misunderstand what pellets are for and if I have the concept right then why is ceramic more appropriate than plastic? Thanks! - Beau aka Raider30 |
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Post by deb193redux on Jan 10, 2010 19:59:14 GMT -5
I understood the initial poor movement you saw was dry. Dry will often be slower than damp. Damp with grit will be slower than damp without grit. The question is: What is the purpose of a "properly" filled bowl. The answer depends on whether it is rotary or vibe. In a rotary the fill level controls the cross section along which rocks slide as the barrel rotates. The plastic pellets can help reach the proper volume, as well as fill in small holes so that when the rocks slide over they are in contact. Since most rotary loads are close to over-weight, the almost weightless pellets are a plus. See the diagram on this web page for an illustration of cross-section (See the diagram at this web page: www.omsinc.org/tumble1.html) - too empty and rocks roll and drop instead of sliding and they chip. too full and they have no room to slide. In a vibe the issue is not fill-level, but rather proper weight. The units are tuned for maximum vibration energy at the spec weight of the full barrel. Half-empty barrels will bounce with too much energy and chipping will occur. Similar to plastic pellets, ceramic pellets also fill in small holes and help maximize contact area. But their mass is much more critical. The vibe is essentially shaking things so that there is reciprocating slide of everything against everything else. Yes, you will see the rocks go round and turn over, but the action is in the small back and forth abrasion contacts and not in the slower journey of the rock round the bowl. When shaking things, mass is important. Imagine shaking a plastic bag full of Styrofoam peanuts - almost no real pressure as peanuts rub against each other. Ceramic pellets have mass. When you shake ceramic and rocks together their mass produces a much more useful reciprocating abrasion - i.e., it has a little pressure. This is the same as why we push down a little bit on a brillo pad instead of just using it like a feather duster - you need some contact force. The force of contact between vibrating rocks/pellets is proportional to their mass, and since plastic has near-zero mass, it does not contribute in any appreciable way to the abrasive action. I have also just reread your original post. I think you were lucky. Grit should be added to damp rocks when the rocks are moving. Think about it, if you put grit in with dry rocks, the very small grit just filters down to the bottom. Once things start moving, the rocks have to pick up the grit, and this does not always happen because grit is heavier/denser than rock. Getting a grit pancake at the bottom can happen. Sounds like you dodged that bullet though. So... wet rocks & ceramic before putting it into the bowl, use rock and ceramic to near-full level. Put about half of the grit on the top of the damp rocks and media and turn it on. In fact you want it as full as you can get w/o the rocks flying out. Then sprinkle in remaining grit slowly so that all rocks get well coated. The after about 2-3 minutes for grit to distribute, spray a little water to get the speed back up. I hope this addresses your questions. |
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raider30
off to a rocking start
Member since December 2009
Posts: 18
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Post by raider30 on Jan 10, 2010 20:25:24 GMT -5
Thanks for the awesome explanation! The description of the vibe action being dependent on weight makes a lot of sense and I wasn't really looking at it like that. It was something I didn't realize about the way vibe's are set up.(then again I'm new to this) Since its already running and has been for the past 7 1/2 hours do you think I can just continue to let it run for the time being? I'll likely shut it off overnight just because of the noise. Then I figure I can rinse everything off, order some ceramic pellets, and start up again in a few days with the pellets arrive. Tony said to run it for 1-3 days, so I'd have 1/2 to 2 1/2 days yet to go. Oh, and the initial movement I saw was almost entirely circular. The rocks just moved around the bottom of the bowl. No turning or flipping. Without the pellets but WITH water/grit do you think they would continue to circle or do you think they would get the better action they are getting now?(just wondering) Thanks again! - Beau aka Raider30 |
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Post by deb193redux on Jan 10, 2010 20:32:05 GMT -5
yes. do not mess with something working well enough.
the action will be less efficient because of the missing mass, but why waste the grit? let ig go 24 hours and change.
I think wet and wet / grit should only differ in speed.
bowls/moels differ and I do not know yours 1st hand. My lot-O rolls over like a rotating ball. My Gy-Roc has more of a torus (around and twisting) motion.
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Post by deb193redux on Jan 10, 2010 20:42:56 GMT -5
here is video where the motion looks right. the grit coating is a little heavy because this is the finer 600g stage and it has already formed some mud.
I think this bowl has too much water. The polish slurry is supposed to be thin, and recipie for obsidian tears are ofetn special, but it looks too thin and foam is forming.
here is damp rock w/o grit. I think there are almost too many flats and preforms in this batch. In a smaller bowl this would not work so well because flats get stuck together. But in a bowl this size, it might work OK
this one has way too much water:
this one is too slow in my opinion, but you do see polish being added while moving:
I would say too much standing water in bottom, but maybe this model had enough energy to move grit up out of water. movement looks good:
this looks too slow too, and there appears to be too much mud on the barrel, but I can see rock so not too much mud on the rock. Not sure exactly what is wrong with this barrel:
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raider30
off to a rocking start
Member since December 2009
Posts: 18
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Post by raider30 on Jan 12, 2010 18:12:21 GMT -5
Thanks again for all the help, especially the videos. It's odd, I've been online since 1996 and yet I seem to always forget what the net has available!
In that first video the rocks are really moving fast, to me anyways. My movement was nothing like that. I mean the general motion was fairly comparable, but nowhere near as fast.
Unfortunately after watching that video I thought maybe I should try to speed up my movement...I thought things looked a bit dry...I should have left well enough alone. I ended up spritzing some more water on the rocks and basically slowed the movement down to 1/4 speed of where it had been. Whoops. Well they were still moving and I could still feel some grit on the rocks so I decided to just leave it running through the night.
In the morning it was moving a bit better, not great though and was really damp and some of the plastic pellets were caked on the sides. So I stopped motion 18hrs after it had begun. Plus there was no grittiness left that I could feel. Last night I washed the rocks the best I could and separated them from the plastic pellets(this was not as easy as you might think because it is around 0 degrees here and so I was doing this with a 5gal bucket, strainer, and a jug of warm water. Heh, it was a real pain in the rear to try to pour while washing the rocks and not get stuff everywhere.) Anyway, they've been drying since last night.
After your post I ordered some ceramic pellets from the rockshed, and those should be here within a day or two. I will hold off restarting the project until I get the ceramic pellets. Then I'll *really* try hard to limit the amount of water and see if I can get things moving decently enough.
The plus side is the rocks have gotten noticeably smoother, especially some of the ones which had sharper broken edges.
One question though(you didn't think you'd make it out of this post without a question did you?): After I clean the rocks there was still some grey residue hiding in some of the bigger cracks/pits. Short of scrubbing each one with a brush(which I really don't want to do) is there a way to get this stuff out? Will it come out on its own as I continue stage 1(220 grit)? Or, is this partially what the burnish is for - to run the rocks around in some soapy water to help clean them off?
Thanks again for the help!
- Beau aka Raider30
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Post by deb193redux on Jan 12, 2010 19:44:02 GMT -5
running for an hour using borax instead of grit should clean them - BUT only if it does not dry. Once dry it is like cement.
You might have to go 24hrs in Borax, or just grind the rocks until the cracks are gone - then no more grit in crack.
if not changing grit size, just keep them wet and reload.
while you do want to learn the max speed for your machine, do not worry too much about faster/slower in the large movement. Most of the action is in the fine reciprocating movement at the frequency of the vibe. The shape of the bowl has more to do with drifting around the bowl.
when the ceramic arrives, fill the bowl with damp ceramic, start the machine, spritz and it should go faster, spritz again and it should go faster. At some point, it will start going slower and just vibrating while standing water pops in little beads.
this will let you know the max speed you can expect. rocks will not move as fast as wet pellets. but it is good to know the max.
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So far does it sound like I'm doing it right?
