dakotabirder
noticing nice landscape pebbles
Member since July 2017
Posts: 77
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Post by dakotabirder on Dec 4, 2017 11:54:23 GMT -5
Newbie question, haven't really found a great answer searching. We have a ton of material we've collected since starting this summer. South Dakota agates, petrified wood, jaspers, quartz, etc. The agates in particular...there's no shortage of material to find, but many of the agates we find have fractures, pits, etc.
Some we can rough tumble out, but for the fractures, many are too deep. Still some gorgeous pieces, and we want to tumble polish despite a small crack. The pieces turn out well, look great until the polish phase, but then the AO polish we use must be fine enough to get into the crack. As a result, we end up with a really nice piece, that has a whitish-looking crack because of the polish.
Do you ever try to seal/fill a crack or pit before tumble polishing? Looking around out here, I see epoxy being used for other purposes, also see super glue and nail polish mentioned in places. Would any of those work? Something to try to fill in or seal off a small crack before the final polish, to prevent the fine AO polish from getting in?
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Dec 5, 2017 9:49:44 GMT -5
I can accept some flaws in my tumbles. I don't like fractures though. In the past I tried super glue to fill flaws. It had some small benefit when applied to a fracture. In some pieces it would not penetrate however. In pits it would loosen over time if sent through repeated cycles and fall out.
These days I do one of two things for fractures. If the fracture runs roughly perpendicular to the surface I simply break it along the fracture. Better two smaller "perfect" pieces than one flawed piece. If the fracture is roughly horizontal to the surface I grind it off. I usually do this when the rock is very close to being ready to move on.
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Post by gmitch067 on Dec 5, 2017 11:15:28 GMT -5
Starbond CA glue has different viscosities which have helped me out in the past. It does not seem to discolor, and I have not seen it fall out during tumbling. I first tumble in 80-grit for a week or three to define the extent of the fracture or void. If the stone's appearance will benefit from the splitting that tkvancil recommends, I will do that. If not... I usually treat it with Starbond Ultra Thin glue to stabilize and fill deep into the fracture(s); Then I use either the Medium or the Thick gel to fill in the rest of the void. I should also add that before applying the Starbond, I flush out the fracture or void with a stiff stream of water from a Water-Pic to remove any debris and trapped 80-grit... This is important if the stone is an agate with a nice window into time.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,685
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Post by Fossilman on Dec 5, 2017 14:28:02 GMT -5
Starbond CA glue has different viscosities which have helped me out in the past. It does not seem to discolor, and I have not seen it fall out during tumbling. I first tumble in 80-grit for a week or three to define the extent of the fracture or void. If the stone's appearance will benefit from the splitting that tkvancil recommends, I will do that. If not... I usually treat it with Starbond Ultra Thin glue to stabilize and fill deep into the fracture(s); Then I use either the Medium or the Thick gel to fill in the rest of the void. I should also add that before applying the Starbond, I flush out the fracture or void with a stiff stream of water from a Water-Pic to remove any debris and trapped 80-grit... This is important if the stone is an agate with a nice window into time. Spot on!!!!! Starbond glues are great and work miracles!
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dakotabirder
noticing nice landscape pebbles
Member since July 2017
Posts: 77
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Post by dakotabirder on Dec 5, 2017 14:30:28 GMT -5
Starbond CA glue has different viscosities which have helped me out in the past. It does not seem to discolor, and I have not seen it fall out during tumbling. I first tumble in 80-grit for a week or three to define the extent of the fracture or void. If the stone's appearance will benefit from the splitting that tkvancil recommends, I will do that. If not... I usually treat it with Starbond Ultra Thin glue to stabilize and fill deep into the fracture(s); Then I use either the Medium or the Thick gel to fill in the rest of the void. I should also add that before applying the Starbond, I flush out the fracture or void with a stiff stream of water from a Water-Pic to remove any debris and trapped 80-grit... This is important if the stone is an agate with a nice window into time. Perfect, just didn't know what type of material to try in a fracture. I ordered some of the ultra thin to give it a shot. The pic below shows what I'm talking about, in this case, some quartz with a fracture that gets filled with white polish material in the polish phase. I have plenty of pieces like this (particularly all the South Dakota agates we've collected...they're a pretty "fractured" group by nature), so just wanted to be able to polish flawed pieces like that without getting these white-filled fractures. Will try your suggestion from now on. Not worried about pits as much in a final product, but will start trying to fill in fractures with the ultra-thin Starbound after my rough-polish phase to see if it helps avoid the following.
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Post by grumpybill on Dec 5, 2017 15:09:33 GMT -5
I've had reasonable success with cleaning the polish residue out (before it dries/sets up) with an old Soni-care toothbrush.
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dakotabirder
noticing nice landscape pebbles
Member since July 2017
Posts: 77
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Post by dakotabirder on Dec 5, 2017 15:45:00 GMT -5
I've had reasonable success with cleaning the polish residue out (before it dries/sets up) with an old Soni-care toothbrush. Good idea, I'll give that a go as well!
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Post by gmitch067 on Dec 5, 2017 17:00:39 GMT -5
Starbond will probably do the trick on that stone, but the Ultra Thin will also cover some of the outer surface as well. You can clean that off by hitting the surface with some 220-grit silicon carbide wet/dry sandpaper before advancing the stone(s) to the next tumble... or... just run the 220 grit tumble twice if you notice the residue.
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mhoecker
off to a rocking start
Member since June 2017
Posts: 6
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Post by mhoecker on Dec 8, 2017 18:18:37 GMT -5
I use an ultrasonic machine to get grit and polish out of cracks and pits. You can see the grit and polish coming out - looks like streaming clouds in the water. A little time consuming since I inspect every rock after each step, but I get better results (or at least think I do).
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Post by gmitch067 on Dec 8, 2017 22:07:08 GMT -5
I use an ultrasonic machine to get grit and polish out of cracks and pits. You can see the grit and polish coming out - looks like streaming clouds in the water. A little time consuming since I inspect every rock after each step, but I get better results (or at least think I do). mhoecker - I thought ultrasonics caused some rocks to split?!?!? Wouldn't the sonics vibrate a crack wider? I was thinking of getting a small machine a few months back but opted for a water-pic when I noted the controversy from other member's comments.
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mhoecker
off to a rocking start
Member since June 2017
Posts: 6
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Post by mhoecker on Dec 9, 2017 10:28:34 GMT -5
I use an ultrasonic machine to get grit and polish out of cracks and pits. You can see the grit and polish coming out - looks like streaming clouds in the water. A little time consuming since I inspect every rock after each step, but I get better results (or at least think I do). mhoecker - I thought ultrasonics caused some rocks to split?!?!? Wouldn't the sonics vibrate a crack wider? I was thinking of getting a small machine a few months back but opted for a water-pic when I noted the controversy from other member's comments. I’ve not noticed any problems but I have no idea how to figure if a crack is bigger/deeper other than eyeballing. Either I’m clueless or lucky.
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