md
off to a rocking start
Member since May 2023
Posts: 3
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Post by md on May 7, 2023 16:36:06 GMT -5
Hi all, I have been collecting thundereggs for a few years and until recently was only using an angle grinder with diamond pads to polish them. I upgraded to a Richardson's dry sander after finding that they're very popular with the local rockhounding community. I've watched several videos and I'm aware of the safety hazards with these machines. My question though is how to prevent eggs from overheating while working with them. I did a trial run with a handful of eggs all in the 2.5-4" range. I worked them as a batch so they had time to cool down between each grit. However, several of them got heat damage (white patches in formerly deep blue agate) on the first grit after what seemed like just a few seconds--definitely after less time than what I was seeing people do in tutorial videos. So my questions are about how to avoid this in the future. Is there a minimum size eggs should be for this machine to avoid overheating? Do you need to be extra careful to use little to no pressure? Any other techniques to prevent this? Thanks in advance!
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khara
fully equipped rock polisher
Member since September 2022
Posts: 1,632
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Post by khara on May 7, 2023 16:42:41 GMT -5
I have not used this machine but I thought I’d seen people dipping the rock in water. A little bowl of water sitting next to the machine? Hopefully some people who’ve used it can give insight.
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Post by creativeness718 on May 8, 2023 21:21:09 GMT -5
I use barely any pressure. No reason to go hard on them, if you start with the right grit it'll go fast
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RWA3006
Cave Dweller
Member since March 2009
Posts: 4,125
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Post by RWA3006 on May 13, 2023 11:49:43 GMT -5
I work a pile large enough to alternate them constantly while grinding. I also save some to do outside in the coldest times of winter and I like to run my saws in a cold shed during the winter to keep temperatures down. I do a few thunder eggs and geodes, but mostly coprolites.
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lapidarycentral
starting to spend too much on rocks
(Brian Rhode) LapidaryCentral.com - Fueling your Lapidary Addiction.
Member since August 2021
Posts: 209
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Post by lapidarycentral on May 19, 2023 14:16:47 GMT -5
As others are saying, light pressure, alternate, and just go easy on them. You should just be putting enough pressure to hold the stone on the pad, nothing more. Let the high speed sander do all the work. Keep an eye on the stone and use your best judgement. If you are overheating, you are trying to go too fast.
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md
off to a rocking start
Member since May 2023
Posts: 3
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Post by md on Jun 4, 2023 16:32:19 GMT -5
As others are saying, light pressure, alternate, and just go easy on them. You should just be putting enough pressure to hold the stone on the pad, nothing more. Let the high speed sander do all the work. Keep an eye on the stone and use your best judgement. If you are overheating, you are trying to go too fast. Thank you! When you say just enough to hold the stone on the pad, are you meaning the sandpaper pad or the rubber pad behind it? Trying to understand if the goal is to have so little pressure that it's really just against the sandpaper (which doesn't lay against the rubber backing on its own) or a little more so that the sandpaper is being pushed flat to the rubber pad.
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lapidarycentral
starting to spend too much on rocks
(Brian Rhode) LapidaryCentral.com - Fueling your Lapidary Addiction.
Member since August 2021
Posts: 209
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Post by lapidarycentral on Jun 4, 2023 21:02:08 GMT -5
You just want it to be against the sandpaper and to hold the sand paper against the rubber pad. If you are noticing the rubber going up when you press the stone, it's probably too much pressure.
Where do you get your sanding pads? It is also possible that you could be getting some that just isn't working with rock. Overall, we've had the best results with ones ordered directly from Richardsons. We've gotten some from hardware stores and also wholesale ordered some, and none seemed to work as good as the ones Richardsons Rock Ranch carries.
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md
off to a rocking start
Member since May 2023
Posts: 3
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Post by md on Jun 4, 2023 21:10:33 GMT -5
You just want it to be against the sandpaper and to hold the sand paper against the rubber pad. If you are noticing the rubber going up when you press the stone, it's probably too much pressure. Where do you get your sanding pads? It is also possible that you could be getting some that just isn't working with rock. Overall, we've had the best results with ones ordered directly from Richardsons. We've gotten some from hardware stores and also wholesale ordered some, and none seemed to work as good as the ones Richardsons Rock Ranch carries. I've been using them straight from Richardson's but had been planning on other sources eventually so that is very good to know. Thank you! I did another test batch on less exciting eggs and didn't have any of the big white "burns" in formerly dark agate like the first time so seems like pressure was the issue, so thanks again for your help and this explanation. Now I've just got to perfect really getting all the scratches out at each grit. I have the angle grinder/diamond pad method down to a science but there's definitely a different learning curve to this!
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lapidarycentral
starting to spend too much on rocks
(Brian Rhode) LapidaryCentral.com - Fueling your Lapidary Addiction.
Member since August 2021
Posts: 209
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Post by lapidarycentral on Jun 5, 2023 12:32:34 GMT -5
You just want it to be against the sandpaper and to hold the sand paper against the rubber pad. If you are noticing the rubber going up when you press the stone, it's probably too much pressure. Where do you get your sanding pads? It is also possible that you could be getting some that just isn't working with rock. Overall, we've had the best results with ones ordered directly from Richardsons. We've gotten some from hardware stores and also wholesale ordered some, and none seemed to work as good as the ones Richardsons Rock Ranch carries. I've been using them straight from Richardson's but had been planning on other sources eventually so that is very good to know. Thank you! I did another test batch on less exciting eggs and didn't have any of the big white "burns" in formerly dark agate like the first time so seems like pressure was the issue, so thanks again for your help and this explanation. Now I've just got to perfect really getting all the scratches out at each grit. I have the angle grinder/diamond pad method down to a science but there's definitely a different learning curve to this! You can use the same trick that you use with a vibrating or rotating lap; sharpie the whole surface or where scratches are, and do it until the sharpie marks are gone. Generally shows when you have all scratches or saw marks out.
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