Our Adventures In Petoskey Tumble Polishing
Oct 10, 2017 14:20:05 GMT -5
Peruano, petoskeycheryl, and 2 more like this
Post by fossilpeeps on Oct 10, 2017 14:20:05 GMT -5
I hope this is in the correct place. I am still trying to navigate these boards.
My hubby and I have been using the recipe that Shawn from The Rock Shed gave us for tumble polishing Petoskey Stones in a Lortone 3A (3lb.) tumbler. So far so good! We are excited.
I will share the recipe Shawn gave us later in this thread.
We have tons of Petoskey stone that we have collected or purchased from other collectors - some from the EAST (Lake Huron) side of the Lower Peninsula, and most of it is from the WEST side of the Lower Peninsula of Michigan. Haven't collected any yet from Drummond Island - which is Devonian Era land also - as is the very upper part of the Lower Peninsula of Michigan. A little bit down near Milan, MI and West of Toledo, OH is also Devonian Era. We have found Trilobites and Brachiopods there. No Petoskey though.
We have been told by C & M Rock Shop in Beulah, Mi (which specializes in Petoskey stone) that the Petoskey stones from the EAST side (eg. Alpena area) of the state are soft, and not worth dealing with. From our experience we agree. However, we have found some wonderful complete Petoskey Stone and Favosite colonies in the Alpena area, and so that is worth the effort to go there collecting. I will try and insert some images if I can figure out how to do it.
Petoskey Stone is from 3 - 5 on the Mohs hardness scale. The hardness depends on where and how it was fossilized. The Petoskey stone on the WEST side of Michigan seems to have fossilized the hardest (in general).
The Petoskey stones we are tumbling are from the WEST (Lake Michigan) side. All of our stones are 2 inches and smaller and have been rounded by the water and sand.
So far, we have done one batch up to STEP 2 in The Rock Shed recipe. We forgot to order 1000 grit aluminum oxide pre-polish, so we are waiting for that to come in. Then we will do STEP 3 and 4.
_____________________________________________________________________________________________________________________________
Here is The Rock Shed recipe for Tumble Polishing Petoskey Stones. ***(UPDATE: 10/17/2017....THIS RECIPE WORKS GREAT!! We are so excited!)
STEP 1:
a.) Fill your Lortone 3A (3lb.) Rotary Tumbler 5/8 to 3/4 full of stones that are a combination of 2 inches or smaller. (Shawn says this recipe works best with a rotary tumbler, and filling the tumbler to the 5/8 - 3/4 level is better than the 2/3 full as per the Lortone directions).
b.) Put in 3 TABLESPOONS of 120/220 Grit.
c.) Fill the tumbler with fresh water to JUST the level of the stones. Maybe a tiny bit under.
d.) Tumble for 4-5 hours. We tumble our stones for 5 hours and the stones looked good. The "raw" and "chalky" look of the stones was pretty much gone and so were the little dents or pocks in the stones. We were surprised to see there was a lot of FOAM on top of the water, but this is normal - we assume.
e.) Drain the stone OUTSIDE. Pour the water, foam and grit through a fine mesh kitchen drainer into a bucket.
f.) Rinse the stones, grit and tumbler bucket with fresh water over the same bucket. Take out the stones and dump the grit into the bucket.
g.) Wash the stones and tumbler bucket with fresh water and mild soap to get all residue off the stones and the bucket. Rinse everything well with fresh water.
STEP 2:
a.) Refill the clean tumbler bucket with the same stones.
b.) Add some SMALL angle cut ceramic cylinders so the tumbler bucket is 5/8 to 3/4 full. The ceramic cylinders will fill in for the lost stone mass that was ground away in STEP 1.
c.) Put in 2 Tbsp. 500 Grit Aluminum Oxide on top of the ceramic cylinder media.
d.) Fill the tumbler with fresh water just up to the top of the ceramic cylinder media.
e.) Tumble for 15 - 18 hours. (Ours came out great at 15 hours tumbling time).
f.) Drain the stones OUTSIDE, ceramic cylinders, water and grit through a fine mesh kitchen drainer into a separate bucket or the same one as used before. Again, there was foam on top of the water.
g) Rinse the stones with fresh water while they are still in the drainer.
h.) Wash the stones, ceramic media and tumbler bucket with fresh water and mild soap to get all residue off. Rinse everything well with fresh water.
STEP 3
a.) Put the cleaned stones and the same small angle cut ceramic cylinder media back into the tumbler barrel. (We needed to add a small bit more ceramic cylinders because of the small amount of mass lost in STEP 2). Fill the tumbler until it is 5/8 - 3/4 full.
b.) Put 2 Tbsp. 1000 Grit Aluminum Oxide Pre-polish on top of the ceramic media.
c.) Fill the tumbler with fresh water just to the top of the ceramic media.
d.) Tumble for 12 hours. You MAY need to tumble for a bit longer. Don't tumble for too long, or you will lose too much rock!
e.) Drain the stones, water, ceramic cylinders through a fine mesh kitchen drainer into a bucket, OUTSIDE.
f.) Rinse the stones with fresh water over the same bucket, while they are still in the drainer.
g.) Wash the stones and tumbler bucket with fresh water and mild soap to get all residue off the stones. Rinse everything well with fresh water.
h.) Set the small angle cut ceramic cylinders aside for another batch. You will NOT need them for STEP 4.
STEP 4:
a.) Divide the Petoskey Stones into 2 or 3 small batches.
Dividing the stones into small batches helps insure that the rocks rotate well with the new ceramic media, and don't rub or crash into one another.
b.) Put the FIRST BATCH into the tumbler bucket.
c.) Add enough 2mm ROUND ceramic media beads to fill the tumbler 5/8 - 3/4 full.
d.) Put 2 TEASPOONS of 3000 Aluminum Oxide Polish on top of the ceramic media beads.
e.) Fill the tumbler with fresh water just up to the level of the ceramic media beads.
f.) Tumble for 12 hours. Check the batch. You MAY need to tumble it for up to 24 hours to reach the desired polish.
e.) Drain (OUTSIDE) everything through the fine mesh kitchen drainer into a bucket.
f.) Wash the stones, 2mm ceramic media beads and everything with fresh water and mild soap. Rinse well with fresh water.
YOUR FIRST SMALL BATCH IS DONE. Repeat STEP 4 with the other batches of Petoskey stone.
_____________________________________________________________________________________________________________________________
Dispose of your sludge grit water in a responsible way.
Shawn of The Rock Shed says this same above recipe works well for other soft stones.
We want to try it on Favosite and fossilized Horn Coral.
If you try this recipe, please let me know how your batch turns out - and please include where your Petoskey is from (East of West side of Michigan) if you know.
Have a nice day!
My hubby and I have been using the recipe that Shawn from The Rock Shed gave us for tumble polishing Petoskey Stones in a Lortone 3A (3lb.) tumbler. So far so good! We are excited.
I will share the recipe Shawn gave us later in this thread.
We have tons of Petoskey stone that we have collected or purchased from other collectors - some from the EAST (Lake Huron) side of the Lower Peninsula, and most of it is from the WEST side of the Lower Peninsula of Michigan. Haven't collected any yet from Drummond Island - which is Devonian Era land also - as is the very upper part of the Lower Peninsula of Michigan. A little bit down near Milan, MI and West of Toledo, OH is also Devonian Era. We have found Trilobites and Brachiopods there. No Petoskey though.
We have been told by C & M Rock Shop in Beulah, Mi (which specializes in Petoskey stone) that the Petoskey stones from the EAST side (eg. Alpena area) of the state are soft, and not worth dealing with. From our experience we agree. However, we have found some wonderful complete Petoskey Stone and Favosite colonies in the Alpena area, and so that is worth the effort to go there collecting. I will try and insert some images if I can figure out how to do it.
Petoskey Stone is from 3 - 5 on the Mohs hardness scale. The hardness depends on where and how it was fossilized. The Petoskey stone on the WEST side of Michigan seems to have fossilized the hardest (in general).
The Petoskey stones we are tumbling are from the WEST (Lake Michigan) side. All of our stones are 2 inches and smaller and have been rounded by the water and sand.
So far, we have done one batch up to STEP 2 in The Rock Shed recipe. We forgot to order 1000 grit aluminum oxide pre-polish, so we are waiting for that to come in. Then we will do STEP 3 and 4.
_____________________________________________________________________________________________________________________________
Here is The Rock Shed recipe for Tumble Polishing Petoskey Stones. ***(UPDATE: 10/17/2017....THIS RECIPE WORKS GREAT!! We are so excited!)
STEP 1:
a.) Fill your Lortone 3A (3lb.) Rotary Tumbler 5/8 to 3/4 full of stones that are a combination of 2 inches or smaller. (Shawn says this recipe works best with a rotary tumbler, and filling the tumbler to the 5/8 - 3/4 level is better than the 2/3 full as per the Lortone directions).
b.) Put in 3 TABLESPOONS of 120/220 Grit.
c.) Fill the tumbler with fresh water to JUST the level of the stones. Maybe a tiny bit under.
d.) Tumble for 4-5 hours. We tumble our stones for 5 hours and the stones looked good. The "raw" and "chalky" look of the stones was pretty much gone and so were the little dents or pocks in the stones. We were surprised to see there was a lot of FOAM on top of the water, but this is normal - we assume.
e.) Drain the stone OUTSIDE. Pour the water, foam and grit through a fine mesh kitchen drainer into a bucket.
f.) Rinse the stones, grit and tumbler bucket with fresh water over the same bucket. Take out the stones and dump the grit into the bucket.
g.) Wash the stones and tumbler bucket with fresh water and mild soap to get all residue off the stones and the bucket. Rinse everything well with fresh water.
STEP 2:
a.) Refill the clean tumbler bucket with the same stones.
b.) Add some SMALL angle cut ceramic cylinders so the tumbler bucket is 5/8 to 3/4 full. The ceramic cylinders will fill in for the lost stone mass that was ground away in STEP 1.
c.) Put in 2 Tbsp. 500 Grit Aluminum Oxide on top of the ceramic cylinder media.
d.) Fill the tumbler with fresh water just up to the top of the ceramic cylinder media.
e.) Tumble for 15 - 18 hours. (Ours came out great at 15 hours tumbling time).
f.) Drain the stones OUTSIDE, ceramic cylinders, water and grit through a fine mesh kitchen drainer into a separate bucket or the same one as used before. Again, there was foam on top of the water.
g) Rinse the stones with fresh water while they are still in the drainer.
h.) Wash the stones, ceramic media and tumbler bucket with fresh water and mild soap to get all residue off. Rinse everything well with fresh water.
STEP 3
a.) Put the cleaned stones and the same small angle cut ceramic cylinder media back into the tumbler barrel. (We needed to add a small bit more ceramic cylinders because of the small amount of mass lost in STEP 2). Fill the tumbler until it is 5/8 - 3/4 full.
b.) Put 2 Tbsp. 1000 Grit Aluminum Oxide Pre-polish on top of the ceramic media.
c.) Fill the tumbler with fresh water just to the top of the ceramic media.
d.) Tumble for 12 hours. You MAY need to tumble for a bit longer. Don't tumble for too long, or you will lose too much rock!
e.) Drain the stones, water, ceramic cylinders through a fine mesh kitchen drainer into a bucket, OUTSIDE.
f.) Rinse the stones with fresh water over the same bucket, while they are still in the drainer.
g.) Wash the stones and tumbler bucket with fresh water and mild soap to get all residue off the stones. Rinse everything well with fresh water.
h.) Set the small angle cut ceramic cylinders aside for another batch. You will NOT need them for STEP 4.
STEP 4:
a.) Divide the Petoskey Stones into 2 or 3 small batches.
Dividing the stones into small batches helps insure that the rocks rotate well with the new ceramic media, and don't rub or crash into one another.
b.) Put the FIRST BATCH into the tumbler bucket.
c.) Add enough 2mm ROUND ceramic media beads to fill the tumbler 5/8 - 3/4 full.
d.) Put 2 TEASPOONS of 3000 Aluminum Oxide Polish on top of the ceramic media beads.
e.) Fill the tumbler with fresh water just up to the level of the ceramic media beads.
f.) Tumble for 12 hours. Check the batch. You MAY need to tumble it for up to 24 hours to reach the desired polish.
e.) Drain (OUTSIDE) everything through the fine mesh kitchen drainer into a bucket.
f.) Wash the stones, 2mm ceramic media beads and everything with fresh water and mild soap. Rinse well with fresh water.
YOUR FIRST SMALL BATCH IS DONE. Repeat STEP 4 with the other batches of Petoskey stone.
_____________________________________________________________________________________________________________________________
Dispose of your sludge grit water in a responsible way.
Shawn of The Rock Shed says this same above recipe works well for other soft stones.
We want to try it on Favosite and fossilized Horn Coral.
If you try this recipe, please let me know how your batch turns out - and please include where your Petoskey is from (East of West side of Michigan) if you know.
Have a nice day!