learn2turn
noticing nice landscape pebbles
Member since February 2011
Posts: 77
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Post by learn2turn on Mar 9, 2011 12:54:41 GMT -5
I'm a newbie. I want to order some supplies and tough rock from rockshed but I have one question I need answered first.
The instructions I've read say 4Tbl grit / 6 Tbl polish to 3lbs of rock. But grit/polish is sold by weight.
Does anyone have the rock to grit/polish ratios specified by weight?
Or at least what's the density of grit and polish, i.e. grams or ounces per Tbl?
(I have a digital kitchen scale that should do the trick better than measureing Tbls)
Oh, I have a mini-sonic vibe someone lent me but I think I'm also going to buy a 3lb rotary so that I can round off rough rock. I don't know if the ratios are the same or not.
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charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
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Post by charles kuchar on Mar 9, 2011 19:38:24 GMT -5
thumbler tumbler 3# barrel is recommended 4oz of grit. i find a 1/4 cup of 60/90 is roughly 4oz and 3 rounded tbsp is same. maybe 4 level tsbp would be that weight of grit. this is only for the tumbler. grit for the vibrator is maybe 6 tsp of 220 grit for 4# of rock. then 1/2 tsp for 500 grit and up... charlie
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Mar 9, 2011 20:07:38 GMT -5
I use about 1/2 the amount of polish as grit. I use 2 heaping tbsps for my 3 lb rotaries (I'm a little light on grit as most people seem to use at least 3 tbsp). As for measuring it. Well exact amounts are really not critical, as long as your not too far over or under. When buying grit I order my 60/90 in 50 lb lots (lasts me a long time). I order all the other sizes in 5 lb bags. My prepolish and polish I buy a pound at a time. I usually only order the smaller amounts about once a year. The 50 lber has lasted me 4 years so far (but I did take about 18 months offf from tumbling)
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Post by 150FromFundy on Mar 9, 2011 21:41:18 GMT -5
One thing to note is that a 3 lb barrel does not hold 3 lbs of rock. 3 lbs is the total load including barrel, rock, water and grit. For a 3 lb barrel, order 2 lbs of rock. That should just fit.
For a 3 lb barrel - fill the barrel 2/3 full of rock - fill the barrel 1/2 full of water - add 3 Tbsp of grit
15 Tbsp of grit weighs 1 lb. That`s the amount for a 15 lb rotary.
Good luck.
Darryl.
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Post by johnjsgems on Mar 9, 2011 22:58:15 GMT -5
Depends on which Mini-Sonic. As a reference, Gy-Roc 2.5 lb vibe uses one teaspoon grit or polish. Their 10 lb. vibe uses 1 tablespoon grit or polish. Amount of polish needed really depends on quality of polish. Many of the inexpensive polish compounds included in kits really are not very good in vibes. A good submicron aluminum oxide works well and in tiny amounts so less expensive overall.
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Post by connrock on Mar 10, 2011 9:32:14 GMT -5
I measure all my grit for roughing in a rotary (60/90) by weight.
A rule of thumb is to use 1lb of 60/90 for every 10 lbs of rocks.
I also use a digital scale from a deli so,,,,,,
If you have 2 lbs of rocks you would use 0.20 lbs of 60/90 grit.
Don't forget,,,,,,this is for a rotary and not a vibe!
Hope this helps,,,
connrock
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Mar 10, 2011 18:32:41 GMT -5
Lmao. Ask 100 tumblers about how they measure their grit and you will get 100 different answers! We all have different ways of getting there!
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Post by connrock on Mar 11, 2011 8:34:28 GMT -5
stefan,,,, Whatever works,,,,,,
Somewhere along the line I read about doing it the way I do and it works for me! Maybe if a friend didn't give me a deli scale I'd be measuring my grit by volume?? LOL
conrock
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Mar 11, 2011 9:15:03 GMT -5
Exactly!
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