Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 11, 2017 22:42:13 GMT -5
Hello,
I do all my final rock polishing in three Diamond Pacific MT4 vibe machines. When I load a new set of stones for final polishing using aluminum oxide, within 24 hours a thick head of foam like shaving cream develops and fills the top of the hopper up to the lid. When I say thick, I mean thick. I can stick two fingers into the top of the hopper and lift out the entire foam plug, leaving some stuck to the walls. Down near the rotating stones the foam is much more bubbly and fluid. Since I check the hopper every night to make sure it is still wet and rolling I see the foam right away. If I squirt it with a little water it will eventually all roll down into the stones and be absorbed by the rolling batch of stones. Once removed or reabsorbed, the foam does not occur again.
This happens without fail on all polishing runs, no matter what kind of stones. I normally use 3 tablespoons of aluminum oxide with each hopper load. I add water until I can occasionally see a "shore line" of white water down in the bottom of the load. I would estimate that there is a half inch deep water pool in the hopper while it's running.
There are no contaminants in the hoppers before loading that I am aware of. The previous use of the hopper would be a burnish run with borax and a tiny bit of ivory soap flakes, but I clean the hopper well before restarting a new polish run.
This has happened across many different purchases of aluminum oxide, sourced from The Rock Shed (good guys).
Does anyone have this happen or know what causes this foaming?
Thanks.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Sept 12, 2017 9:01:37 GMT -5
I know that AO polish does foam but as to why I'd be unsure. When I used to polish in the rotary I'd always have a healthy head of foam when opening the barrel. Now that I use a vibe not so much.
I run a Thumlers UV18 so I don't know much about the mini-sonic. Just started a polish run. I use a thickener so I start a little on the wet side, add polish then thickener. The polish was beginning to foam before I added the thickener but stopped as the thickener worked in. In my vibe if there were water at the bottom then I'd definitely be too wet .... far too wet. Maybe you have too much water, but as said not familiar with the mini sonic.
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ChicagoDave
has rocks in the head
Member since June 2016
Posts: 720
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Post by ChicagoDave on Sept 12, 2017 10:46:00 GMT -5
I don't have an MT4, but I use a 1/2 teaspoon of polish in my (4 pound) Lot-O and have no standing water. I simply wet the rocks and then dump out the water. 3 tablespoons seems like a TON of polish!
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Post by Drummond Island Rocks on Sept 12, 2017 10:48:11 GMT -5
I just finished a load of mixed rocks in an MT-4. 1/2 teaspoon of A/O and 1 tablespoon of borax. No foam at all.
Chuck
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 12, 2017 11:07:48 GMT -5
tkvancil, Thanks for replying. Interesting to hear that you had foam when polishing in a rotary. I used to use a rotary for polish and I don't remember ever having the foam, probably because I was never opening the barrel until days later. It was when I changed to a vibe that I had it. I guess as they say, "experiences may vary". Regarding water, the UV18 and the MT4 are very different animals. The UV18 creates a powerful cyclonic roll not only bottom to top but also sideways around in a circle so very little water is needed. The MT4 has a vertically oriented spin like a cylinder rotating bottom to top on a horizontal axis. If there isn't at least the amount of water I mentioned then the stones dry quickly and slow to a stop and then turn into concrete before I can get back to check on it. I have noted that if there is much more water than I mentioned then the foam is more bubbly and wet, but then the excess water slows down the roll of the stones and is counter productive. It took me a long time of trial and error to find what I "think" is the right water level in my situation, but who knows? Thanks again.
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 12, 2017 11:12:38 GMT -5
I don't have an MT4, but I use a 1/2 teaspoon of polish in my (4 pound) Lot-O and have no standing water. I simply wet the rocks and then dump out the water. 3 tablespoons seems like a TON of polish! Wow. I'll have to try a load more like that and see what happens.
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 12, 2017 11:13:39 GMT -5
I just finished a load of mixed rocks in an MT-4. 1/2 teaspoon of A/O and 1 tablespoon of borax. No foam at all. Chuck Okay, maybe need to rethink my setup.
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Post by Drummond Island Rocks on Sept 12, 2017 11:35:48 GMT -5
I just looked the instructions on an MT-4 and it says "2 level teaspoons of polish". So I guess I have not been using enough. I assumed since the capacity is the same as the lot-o that the recipe would be the same. instructions PDFChuck
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 12, 2017 13:42:23 GMT -5
I just looked the instructions on an MT-4 and it says "2 level teaspoons of polish". So I guess I have not been using enough. I assumed since the capacity is the same as the lot-o that the recipe would be the same. Yeah, I originally started with instructions like that and other tutorials before I ended up with the recipe I use now. Although you have to wonder who wrote the instructions for the MT4 because in one place (Step 1C) they say that the stones will circle down through the center like a washing machine and that's flat absurd for this machine type. Apparently they have never actually seen an MT4 in action because the hopper is a horizontal cylinder with flat "sides/ends" designed to roll the load en masse horizontally as a cylinder. Also they say that you should never actually see water in the hopper, but my experience has been that if I look down into the rolling stones and don't occasionally see a "shoreline" edge of water way down deep at the bottom, then by the time I return to check on it that evening the load will be concrete. Lastly they say that the polish stage should be 1 to 2 days. EEEeeeeee ...wrong, but thank you for playing. I usually need 7 to 9 days. I guess you have to take manufacturer instructions with a grain of salt. I think there's a lot of cut and paste going on from other machine types. So I guess my best move here is to try a load with a little less polish and add some borax as a foam or gas cutter and see what happens. Thanks for replying.
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Enigman
starting to spend too much on rocks
Member since December 2013
Posts: 163
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Post by Enigman on Sept 16, 2017 10:56:41 GMT -5
FOLLOW-UP: After the above discussion, I started a load in the MT4 with 2 tablespoons of polish and one tablespoon of borax. Not one bit of foam developed. Not only that, but the slurry of polish appeared to be much more "creamy" and covered the stones better than without the borax. So it appears I can cut down on the amount of polish used. I will permanently adopt the borax addition and experiment further to see how much polish I really need, maybe even just one tablespoon. Thanks to all who replied.
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