JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 807
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Post by JR8675309 on Sept 6, 2021 21:57:40 GMT -5
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Sept 6, 2021 23:23:37 GMT -5
Three things come to mind 1) How thick is the pan? are you just going to grind thru it because cast iron is not that strong and it can be very soft. 2) What about the weight? the motor and base are designed for AL are you going to upset the balance? 3) is the pan flat or is it dished? It must be laser flat of it will not grind the way you want. Several people have looked into this but no one has ever reported back. I know it is hard to get a used pan because it is so easy for people to sell them for AL scrap but I also have never checked what it would cost for a metal shop to build a few. I wonder if you could use one of these other pans to do final polish in with a pad in the bottom. A dealer friend of mine uses some type of screen on the bottom of the pans to protect them and make them last. He claims it keeps the pans from wearing out. I will try to get the information. Does Lortone sell the pans?
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JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 807
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Post by JR8675309 on Sept 6, 2021 23:31:00 GMT -5
rewdownunder, Minn Lap Supply sells the 20" for 195.00 for the grinder pans per their catalog but I emailed to be sure. the 15" are 120 and 125 for grind and polish respectively.'U;d give ti see the screen you're referring to. I do think the cast iron may be too heavy... would have to get a weight on it. All good ideas.
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herb
spending too much on rocks
Member since November 2011
Posts: 469
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Post by herb on Sept 7, 2021 9:24:38 GMT -5
When the pan for my 15 inch lap became too worn out, I looked into replacement options. I was mostly seeing if i could save some money from the $120 plus shipping a new one would cost. I called a few machine shops. They quoted me about $300 to make one. They both insisted that they would have to start with a 2 inch thick slab of aluminum and machine it out! I was expecting they'd make the round bottom out of 1/4 inch thick sheet and then bend some 2 inch wide 1/4 inch sheet around the sides and weld it together before machining the bottom flat. But they said the welding would mess up the temper of the aluminum. I ended up finding a small machine shop that would machine the surface of my pan flat for $50. A decent savings from 120 for a new pan and I can probably get it machined 2 more times before I'd start worrying about the bottom becoming too thin. When I get to that point, I might see about having the shop cut out a matching flat insert disk that just goes in the old pan and put a bead of caulk around the edge to prevent water and grit from getting underneath. I figure the bumper would keep the caulk from getting ground away. Three things come to mind 1) How thick is the pan? are you just going to grind thru it because cast iron is not that strong and it can be very soft. 2) What about the weight? the motor and base are designed for AL are you going to upset the balance? 3) is the pan flat or is it dished? It must be laser flat of it will not grind the way you want. Several people have looked into this but no one has ever reported back. I know it is hard to get a used pan because it is so easy for people to sell them for AL scrap but I also have never checked what it would cost for a metal shop to build a few. I wonder if you could use one of these other pans to do final polish in with a pad in the bottom. A dealer friend of mine uses some type of screen on the bottom of the pans to protect them and make them last. He claims it keeps the pans from wearing out. I will try to get the information. Does Lortone sell the pans?
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Post by roy on Sept 7, 2021 11:09:25 GMT -5
huh i think its worth a try it should work as long as the pan is flat
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JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 807
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Post by JR8675309 on Sept 8, 2021 7:53:14 GMT -5
Thanks for the feedback y'all. roy, it turns out Home Depot has an Al drain pan (for water heaters) that is 20" in diameter. to rewdownunder 's point, it would weight significantly less than a cast iron but could be too light. It's compelling b/c it's only 16 dollars. Minn Lapidary Supp emailed me and said he had backstock 15" and 20" pans (and they're on his website) but he doesn't have anymore rewdownunder . so my alternative is to get really good at cleaning pans or maintain the hope that laziness will win out and I can have a facsimile or machined one do the job In the meantime, I've asked my friend for advice as he has machine shop equip and his dad had a machine shop. I'm hoping that could go somewhere.
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AzRockGeek
has rocks in the head
Member since September 2016
Posts: 682
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Post by AzRockGeek on Sept 8, 2021 8:42:48 GMT -5
Research sand casting. The pan should be a relatively easy project, just need to get a few casting supplies.
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Sept 8, 2021 9:36:18 GMT -5
The Home Depot pan may be good for polish as you will have a pad in it. While extra pans are nice to just use one for each grit you can get almost the same production by running several batches of rocks at the same grit before changing to the next grit. Extra pans are nice to have but you still have to clean them every time. You can not leave a pan with grit sit even overnight because if it hardens at all there is a major price to be paid. Ask me how I know this. Keep your eye on the market for another use Lap It is almost the same amount of work to have two laps running at the same time as one. Does not have to be the same brand just about the same size.
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JR8675309
freely admits to licking rocks
Member since August 2019
Posts: 807
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Post by JR8675309 on Sept 8, 2021 11:51:58 GMT -5
rewdownunder see, uh oh. I just did that last Ugh this for the first time. Sigh. Left tit right out... did t even think about it. Also it sounds like I have a directive to buy a new flat lap? Got it!
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Post by HankRocks on Sept 8, 2021 12:11:36 GMT -5
Thanks for the feedback y'all. roy , it turns out Home Depot has an Al drain pan (for water heaters) that is 20" in diameter. to rewdownunder 's point, it would weight significantly less than a cast iron but could be too light. It's compelling b/c it's only 16 dollars. Minn Lapidary Supp emailed me and said he had backstock 15" and 20" pans (and they're on his website) but he doesn't have anymore rewdownunder . so my alternative is to get really good at cleaning pans or maintain the hope that laziness will win out and I can have a facsimile or machined one do the job In the meantime, I've asked my friend for advice as he has machine shop equip and his dad had a machine shop. I'm hoping that could go somewhere. The drain pans sound interesting and for $16 it's worth a try. I have the feeling that's it's not going to work well for two reasons due to the lightness(thin metal). First I think the tightening bolts are going to bend the sides of the pan and fail to achieve a tight grip causing the pan to move. On occasion where I do not tighten the pan bolt tight enough, the pan begins to move or more accurately spin within the vib plate, not fatal but the grinding diminishes. Second and more problematic, I think the vibration is going to flex the bottom of the pan and could lead to the vib motion being up/down. That would not be good for any rocks in the pan. Now maybe the pan can be secured tightly and maybe the weight of the rocks will keep the pan bottom from moving up and down. Only one way to find out. If you do go this route, I would put extra cushioning in underneath the center of the pan, even if you eliminate any up/down movement, there is still a chance that the center of the pan will deflect downwards due to rock weight, extra cushion/support in the pan center should prevent this. (The above is my opinion on what I think might happen, trying it out could prove my fears to be unwarranted) As far as extra pans, I only use 2, one for first 3 stages, and 1 with pad for polishing. Never saw the need to have a pan for each stage, I just rinse out the pans after every stage and every use. As with tumbling you will find that you might be running the same rock through the first stage(coarse) multiple times until you get all the saw marks removed. I clean out after every run. It's not a good idea to keep adding grit and running the first stage without a cleanout. Too long a coarse run without cleanout will result in a 1/8" or more of thick rock/grit slurry. That can be a real mess.
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Post by Rockindad on Sept 8, 2021 18:52:12 GMT -5
I do not have a vibe lap and am only reading this thread to gain knowledge about them in case I am able to get a deal on one, so take what I say with a grain of salt. I have however used many of the water heater drain pans you mention and I doubt it will work for you- they are flimsy, as in bend with your bare hands flimsy. HankRocks went into plenty of detail so I won't repeat it. Honestly though, for sixteen bucks I would probably have to give it a shot.
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herb
spending too much on rocks
Member since November 2011
Posts: 469
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Post by herb on Sept 9, 2021 10:11:52 GMT -5
The drip pan might work if you securely glued a piece of 3/8 or 1/2 inch plywood disk under it. Orherwise I think it will flex too much with the weight of the rocks. Even with that, I don't think it would take very long to grind thru it. You could take it a step further and buy a piece of 1/4 inch thick hardened aluminum to put inside of the pan. But you'd still have the problem of not being able to se sure the pan in the lap because of the flimsy sides. A little further engineering ingenuity might solve that problem too.
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herb
spending too much on rocks
Member since November 2011
Posts: 469
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Post by herb on Sept 9, 2021 10:18:34 GMT -5
Actually, I just thought of an idea. Make the pan base and sides out of wood. Coat the whole thing with some paint or better yet waterproofing. Maybe that black do it yourself truck bed lining stuff. Then get some hardened 1/4 inch aluminum sheets to make pan bottoms out of. The hosing bumper in the pan should keep the sides from getting eaten up and the wood body should be strong enough to keep its shape and be secured in the lap.
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