Post by rollingstone on Oct 15, 2005 17:00:37 GMT -5
[glow=red,2,300]FINAL UPDATE NOVEMBER 18, 2005[/glow]
[glow=red,2,300]I first posted this more than a month ago after coarse grind was over, and I've been updating this thread after each grinding stage, but I haven't bumped it back to the top of the board until now, now that everything is finished. It had dropped to page 10 on the photo list.[/glow]
This is patterned petrified "something". It is some kind of petrified wood, but is very different than anything other wood I've found, and the reason for the unusual pattern remains a mystery. Ideas always welcome....
I've shown regular-sized pieces of this stuff tumbled before, all from the same original chunk. I still had this palm-sized piece leftover and wondered what it would be like to tumble it whole. At 230 grams (just over half a pound), this is the biggest thing I've crammed into my 6lb barrel. It's a rectangular-shaped piece, about 3.5" by 2.5" by 1" thick.
I've been keeping a photo journal of my efforts, the pics are shown below. Surprisingly to me, the rock only lost about 1/8th of its mass from rough rock to polish. It weighed 230 grams rough, 205 grams after 42 days of coarse grind, and 200 grams when polished.
0 days, just a brown rock:
0 days, when wet. The colour is wrong in this pic, but I wanted to show that some pattern is visible when wet.
After 8 days 60/90
After 16 days
Now I could see where I wanted to go with this, so I spent 3 tedious hours with a Dremel tool to try and remove the rough spots. I would have thought I could have ground the stone right away in 3 hours... it really is a slow process.
After 24 days coarse:
After 32 days 60/90.
There were still some rough spots and self-sustaining chippy areas after 32 days, so I dabbed clear casting resin in the rough areas to hopefully stabilize them. Then back into the barrel for 10 days, total 42 days:
So that's where I am now. I did add a bit more casting resin to the remaining rough spots (not shown). Casting resin is so soft it can be scratched with a penny, so I'm hoping that it will wear smooth in fine grind.
[glow=red,2,300]Here's a late October update.[/glow] I've now completed fine grind (8 days with 120/220). The excess casting resin ground away nicely. Doesn't look much different than coming out of coarse.
[glow=red,2,300]Another update - November 5.[/glow] Now finished 9 days of 500F silicon carbide pre-polish:
[glow=red,2,300]Final update - November 18.[/glow] There are some fractures, which is typical of the petwood I find, but I'm thrilled with the outcome. I will post a few more pics of the polished results in a new thread. Now to try something even larger...
[glow=red,2,300]I first posted this more than a month ago after coarse grind was over, and I've been updating this thread after each grinding stage, but I haven't bumped it back to the top of the board until now, now that everything is finished. It had dropped to page 10 on the photo list.[/glow]
This is patterned petrified "something". It is some kind of petrified wood, but is very different than anything other wood I've found, and the reason for the unusual pattern remains a mystery. Ideas always welcome....
I've shown regular-sized pieces of this stuff tumbled before, all from the same original chunk. I still had this palm-sized piece leftover and wondered what it would be like to tumble it whole. At 230 grams (just over half a pound), this is the biggest thing I've crammed into my 6lb barrel. It's a rectangular-shaped piece, about 3.5" by 2.5" by 1" thick.
I've been keeping a photo journal of my efforts, the pics are shown below. Surprisingly to me, the rock only lost about 1/8th of its mass from rough rock to polish. It weighed 230 grams rough, 205 grams after 42 days of coarse grind, and 200 grams when polished.
0 days, just a brown rock:
0 days, when wet. The colour is wrong in this pic, but I wanted to show that some pattern is visible when wet.
After 8 days 60/90
After 16 days
Now I could see where I wanted to go with this, so I spent 3 tedious hours with a Dremel tool to try and remove the rough spots. I would have thought I could have ground the stone right away in 3 hours... it really is a slow process.
After 24 days coarse:
After 32 days 60/90.
There were still some rough spots and self-sustaining chippy areas after 32 days, so I dabbed clear casting resin in the rough areas to hopefully stabilize them. Then back into the barrel for 10 days, total 42 days:
So that's where I am now. I did add a bit more casting resin to the remaining rough spots (not shown). Casting resin is so soft it can be scratched with a penny, so I'm hoping that it will wear smooth in fine grind.
[glow=red,2,300]Here's a late October update.[/glow] I've now completed fine grind (8 days with 120/220). The excess casting resin ground away nicely. Doesn't look much different than coming out of coarse.
[glow=red,2,300]Another update - November 5.[/glow] Now finished 9 days of 500F silicon carbide pre-polish:
[glow=red,2,300]Final update - November 18.[/glow] There are some fractures, which is typical of the petwood I find, but I'm thrilled with the outcome. I will post a few more pics of the polished results in a new thread. Now to try something even larger...
.
