Dave Austin
starting to spend too much on rocks
Member since January 2008
Posts: 104
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Post by Dave Austin on Jun 6, 2009 12:39:44 GMT -5
Hi, we bought about 45lb of soronan moss agate about 18 months ago but we are having real problems with it because it seems that nearly every slab we cut from it we are finding lots of pits, it doesnt matter how much we try to grind the pits out they just seem to run all the way through the rock. This of course causes real problems when you want to polish because it just collects in the pits. Does anyone know if there is way of filling the pits that would allow the normal grinding, sanding and polishing process to be carried out successfully. Also the little yellow swirly areas do not take a polish, again they feel like pitted areas. We have managed to get a few nice peices out of this batch, but nowhere near enough. I have posted a picture of it below: If anyone can suggest anything that would be great, I have heard of Opticon but I don't really know how this works or if it's suitable for this application. Thanks again Dave
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on Jun 6, 2009 13:04:53 GMT -5
Yeah, unfortunately, very often moss and plume type agates do not have the mineral inclusions fully replaced with silica which leaves dusty or soft pits throughout the rough. Essentially they are oxides and hydroxides that are still in their natural state. I've had a little success filling deeper pits with the thicker formula Hot Stuff but with shallow, dusty soft spots the Hot Stuff does not penetrate very deep and tends to tear out during the sanding process. Opticon might prove a better solution because it's designed more for penetration but I find the Opticon process a bit tedious and to be frank, unless the piece is both rare and spectacular, I pretty much reject rough filled with pits or soft spots as being too friggin much trouble. After all, each slab or mostly finished cab has to be treated. Lapidary work is a slow enough process without all those extra treatment steps which usually yield limited results. I've reached the point where I will not buy moss/plume rough or slabs without having them in hand and dry so I can judge their quality. Lately, it seems, as the Chinese are staking out many rough production sites and taking the cream from the top, lots of crappy second grade rough is hitting the markets. Much of this looks pretty wet but is essentially unusable except for decorating fish tanks. So many mail order sales pictures of slabs and rough are taken wet and I've been ripped off too many times......Mel
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Post by texaswoodie on Jun 6, 2009 14:40:47 GMT -5
What Mel said. I don't even like the West Texas stuff for that reason. Another thing is fractures. AZ wood is one of the worst and many of the western agates are just too pitted and fractured for me to deal with.
Curt
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Jun 7, 2009 11:17:22 GMT -5
I agree with Mel. Super glue works pretty good but it adds a fair bit more work. If I do use it I put it on after the 2200 and before the polish. Let it dry over night, the do the 2200 over again. Then Polish if it compleatly filled the pit. Otherwise put on some more glue and repeat. It has to be one you really like to make it worth while.
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highplainsdrifter
fully equipped rock polisher
Member since December 2008
Posts: 1,266
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Post by highplainsdrifter on Jun 9, 2009 11:23:20 GMT -5
I've had decent success like this: 1. Grind,sand and prepolish through 1200 grit Nova 2. Use the thick, yellow bottle Hot Stuff and EZ-ZAP Superglue accelerant. Spray the pit first, then fill with glue and spray again. 3. Go back to the 1200 wheel and grind top part of super glue down, but not the whole way. 4. Go to the 3000 grit pre-polish wheel and grind superglue down to surface. 5. Polish with diamond on canvas pad, but don't let it get too hot.
When grinding the glue use lots of water and don't let it get hot. If it drys or gets hot, the glue can peel out.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,456
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Post by Sabre52 on Jun 9, 2009 20:22:12 GMT -5
Great information HPD! I've never really been shown how to do those pit treatments, just kinda felt my way along. Now I can see I've been going back too far on the wheels and probably getting the cabs too hot so the glue tears free. Thanks for the correct process info!......Mel
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Post by Hard Rock Cafe on Jun 10, 2009 15:34:19 GMT -5
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