rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 29, 2012 14:11:59 GMT -5
Hi, Tony - PM sent Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 25, 2012 19:38:24 GMT -5
Hi, all - Thought I might upload some pix of a nifty dust containment and exhaust system I built for under $50. I've seen WAY too many folks in videos omline not using respirator masks - maybe because they think the water or oil keeps the dust out of their lungs - wrong!! The water or oil actually concentrates the rock dust in an airborne mist. With this rig, you can at least not do near as much damage grinding "maskless". It really works well and I have almost no dust on my bench outside the containment after 6 months of use. Here's the rig with my Inland lap inside it. The container is just one of those cheap, plastic tubs from Home Depot with a hole cut in the side maybe a foot and a half wide - ~$8 The dark blue hose coming out of the box is just a couple feet of 2" ribbed hose from Ace - like 1 or 2 bucks. There is a 2" PVC fitting that screws together on the side of the plastic tube that you just shove the hose into and it fits tightly enough. Here's a pic of the suction fan (a 12V bilge blower for a large boat) strapped to the side of my bench. The fan is the dark blue thing just after the PVC fittings. Fan - $18.99 buy it now at ebay, free shipping. PVC - had 'em laying around, maybe $8 Here's the exhaust hose (2 cheap dryer hoses taper together) that carries the dust from the lap out of my garage - ~$6 Here's a pic demonstrating just how much suction this setup generates. (like 800cfm) The clear plastic is just a large zip lock freezer bag cut to lay it out and taped to the plastic tub. It has lasted just fine since they are pretty thick: And here's a pic of the old 12V, 15A power supply I rescued from the trash at work and fixed a long time ago. This particular fan pulls around 7.3A or so at 12V. You can pick up a 12V, 10A switching power supply much smaller for super cheap on ebay. I put a 20A circuit breaker switch in line with the 120VAC input from a wall socket after this pic was taken. You could just plug the thing in but I'm lazy and the plug is behind my toolbox. Anyhow, this thing was pretty easy to put together and works like a charm. The bilge blower fan is like 800cfm and moves a serious amount of air. And I no longer have a taste like concrete in my mouth after a nub grinding or cab forming session. You just have to wipe the dust off the inside top of the tub every few days so's you can see what you're doing. To clean out the rig, you just pull out the blue hose, disconnect power to the lap, and unsnap the plastic tub from its lid, take the lap off the lid and take 'em outside and hose 'everything off. Do your lungs a favor and give it a shot! C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 25, 2012 18:46:25 GMT -5
Check out ebay - I've found 2 or 3 realy good motors there, new and low-priced, in the past year. c-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 22, 2012 23:46:19 GMT -5
Ok, the second side of the slab only took around 12-14 hours. Looks like the saw blade or vise didn't walk on this side. Or I was able to grind them off on my flat lap and don't remember. It did have the nub and groove on this side but I stuck the approx. 3 or 4 pound lead weight right over that spot but perpendicular (if such is possible with a near circular shape - lol) rather than parallel to the edge to spread some of the weight towards the center and also a couple of 1.5 pounders taped to a veneer wood slice in the center. I took the edge weight off for the last 4-5 hours or so and left the weights in the center in place so as not to end up with an angled surface. Did the ol' pencil grid test and it looks dead flat.
The first side took right at about 48 hours due to the saw marks on 2 edges and the fact that I couldn't see how angled they were for a while and didn't weight down those spots until halfway through.
I spent another 6-8 hours letting some of the rocks that spent the night with the big guy grind. One is a 9" x 6" slab of Teepee Canyon agate that got WAY out of whack when the blade on the rock club's Lortone shifted (needs the right flange and shims) and also the vise walked. I tried to cut from the other direction to fix it but the vise walked again after they "fixed" it and I've had that slab in rough grind whenever there's room probably close to 200 hours. It was about 1/8" high in the middle and is still not quite flat as my pencil marks still extend a good inch in from both ends of it. It's an incredible slab with a number of full patterns across it that I cut from a chunk I'd bought and is worth the effort because I'm sure I'd never be able to afford one that big and nice.
I was going to leave off of the big Opal Butte Jasper slab and recharge the pan and grind the Teepee Canyon over night but figured I'd best stick with the program and keep up work on Donnie's slab. So, it's on to 220 grit for the side that finished 60/90 this AM. I figure I'll run each side of it around 20 or 24 hours just to make sure it's good and ready for the fine grit jiggles when I get to those. I could probably get away with a lot less because Oregonian thundereggs and their matrices polish really well and quickly with this vibe lap. But - the old adage - the longer you run the rougher grits, the better the shine and the less time required on the fine and polish phases... at least that's what they say - lol. So I'll have to tamp down my impatience and put in the time like I should. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 21, 2012 16:35:02 GMT -5
John - I tried using rings once but found that they get pushed up and off of slabs or "poor man's nodges" by anything adjacent that doesn't have a perfectly vertical edge. The tubing is just too light and just about anything, including the rock it surrounds, can get up under and lever it off if it has a slanted/angled edge.
Actually, these pix show me committing a no-no which is not covering the entire surface of the nodules/chunks in duct tape. I was able to do this only because the slab is so big that its "jiggle buddies" can't change the position/order they are in. They can rotate but not change positions with each other. So, I was able to save some tape by just doing every other one. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 21, 2012 16:24:35 GMT -5
John - I do have an 8" Inland spinner lap that I wear out far too many 100 grit disks on grinding nubs rather than cabs.
As far as other methods to remove the nubs, actually the typ. 1/8" wide and really deep groove that occurs just before the nub left when the slab/nodule half breaks off is the biggest problem. When I build my saw, it will have a feature I've designed or will design, depending on which method I go for, to keep this from happening. I have been told that one way to stop this is to slow the feed way down at the end of the cut. I haven't been able to test it but, given I'd know my feed rate and could measure the length of the cut, it wouldn't be too hard to design a timer circuit that could be set to lower the voltage to my feed motor after a certain amount of time. Especially since my feed will be digitally controlled anyhow.
Donnie's slab had a giant nub on it - naturally since it is huge - but I was able to grind it off. Took some doing as it was like 3" long, 5/8"-ish wide and a good 1/2" tall. The biggest problem with it is that either the saw vise "walked" at the beginning of the cut - something I've seen using the 18" Lortone at the local rock/gem club - or the flange washer was too small for a thin lapidary blade and the blade sorta flexed at the beginning of the cut. Maybe due to the sharply slanted shape of the nodule edge. This is, along with the surface area of the slab being so large, one of the reasons the rough grind is taking so long on this beautiful beast of a slab. You can pretty easily see by looking at both sides that this slab was probably one just before the heel/end cut. I have an idea how to prevent this junk on the saw I build, as well, but it's sorta iffy if I can pull it off without it being something that wears out a lot..
I can't begin to imagine how big this Opal Butte Jasper nodule was but sure wish I had a slice like this one. I think I've seen "westcoastgems" on ebay listing some that were like 8-12lbs+ but this thing had to weigh over 50lbs when it was dug up.
Later, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 21, 2012 2:16:28 GMT -5
Ok - 3 hours on the other side to grind down the saw marks there and now moved to dead center to run until morning to make sure the slab is still flat. A lot longer grind than usual, especially using 60/90 grit rather than my usual 120 grit 1st grind but I reckon it is because the slab has so much more surface area to flatten than usual. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 20, 2012 20:29:10 GMT -5
Thought I'd up a couple of pix of Donnie's humongous Opal Butte slab being ground in my 20" Lortone "jiggle pan". This thing is really huge and could qualify as one of Earth's tectonic plates! 12 1/4" x 11 1/2". I taped 3/8" plastic tubing around the edge to protect it and the wood slats are there to keep the tubing from riding up over the edge when some other rock shoves on it. The slab isn't weighted because, heck, it already weighs7-10 pounds! The big, tall chunk of Crazy Lace with the lead ingot strapped to one side is in there for 2 reasons. 1) Because it is super un-flat on one side due to the freaken nub/groove left on it by the seller and... 2) The biggest reason is to be sort of a "traffic cop". The big slab is really heavy and, without someone else in the pan of near weight, would tend to really throw its weight around and just sit in one spot if it - typically when you have one biggie and the rest much smaller - felt like it. The lace is heavy enough to push on the big slab enough that it has to take notice. The two really small rocks act as "wedges" that serve to also keep everyone moving. 16 hours later... So, after taking a look at the slab following an overnight grind with 60/90 grit, I noted that the slab was flattening out pretty well, except... One side is a bit heavier and also, the nub-groove and saw marks left by whomever cut this one, though present on opposing sides, are much deeper and extensive on one side of the slab. To compensate, I taped a 3lb lead ingot over this area that I'll probably remove after 6-8 more hours. This will, also, keep - to some extent - from grinding past the nice pattern in the center too much. I've had to do this a LOT with slabs because almost none of the ebay sellers take the time to knock off the nubs on their nodules or slabs. You end up using weights to sorta rock the slab end to end so that you don't have to grind a 16th of an inch off the whole thing to make up for the groove in front of the nub. On the other hand, it IS the "rough for cabbing" page and most folks probably buy chunks to cut cabs from rather than for polished specimens. Here's a pic of the "continental plate" slab with the weight atop and some new buddies in the pan since the others got good and flat overnight... Oh yeah, this rig has made a real mess of my back porch/lanai but it's worth it. And the fan is to cool ME, not to cool the vibe - and, also, to blow away the mosquitoes at night... and for cooling since this IS Florida and nighttime humidity means no respite after the sun goes down. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 16, 2012 0:20:10 GMT -5
Hey Kev - I haven't gotten a break to go ahead and modify my vibe lap with the awesome offset shaft you made for me but I had a thought last night: With the 3mm offset, I might end up slinging the lap pan twice as far - 6mm. No? If it ends up being too radical, is a 1.5mm offset shaft doable? I won't know until I fire the thing up but just in case, I figured I'd ask. Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 16, 2012 0:05:24 GMT -5
I like end cut/heel slabs, too, and the bigger ones I usually include in my specimen collections - I call them "poor man's nodules" - lol Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 9, 2012 18:07:28 GMT -5
I have 20" "jiggle pan" lap and could polish it for you. No charge. It doesn't do too shabby of a job once you solve the up/down hopping/end thrust bit. Actually, I usually end up using it to "finish" polished nodules I've bought since there usually seem to be very fine micro-scratches left by the pad or wheel used. Big hunka lead overnight on a SnO charged pad and, voila! PM me if you want to do it. C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 9, 2012 18:01:31 GMT -5
"... does the price of gas go down at the same time as the price of crude oil drops?...)
No, but gas stations go through so much that the price can drop as early as a couple of days to a week later. Maybe even shorter as it seems the prices fluctuate every day. That said, I wouldn't expect rock shops' or ebay price to react nearly that fast but surely cerium should have gone down by now, almost 11 months after the collapse of the market. I have seen where the large vendors/importers are paying - as of this Spring - only a bit over a quarter of what they were paying 12 months ago . This hobby is expensive enough as it is, ya know? C-ya, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 9, 2012 17:52:08 GMT -5
How much of a difference - if any - has anyone noticed between the "premium" and the "super" cerium? Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 8, 2012 1:59:13 GMT -5
"... CeO is $25/lb at the Rock Shed. 5 pounds is $100..."
Woohoo!! Now, that's more like it! This post came while I was - slowly - typing the previous rant. From the pic, it *looks* like it's the white, sub-micron "good stuff" and not the pink or brown "optical grade". I had not looked at the RS in a good while because the price was high and then, later, they were out of CeO and SnO. If it is the "super cerium", it looks like I finally might actually get my Big Diggins aggies shined up without a lot of undercutting of the matrix. Thanks, Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 8, 2012 1:45:13 GMT -5
"... The prices in your links are for pallet or container quantity. Those buying that volume are paying less. Likely us little guys must clean up existing inventory before we see new prices..."
I'm sure that rock shops have always gotten their cerium, directly or indirectly from vendors whom have imported large amounts. As to cleaning up existing inventory: At the prices I've seen, I would imagine sales are way down and this inventory will languish for a good long time until a new shop comes along that has paid current prices. At that point, I reckon they'd have to lower their price to compete and probably have to take some loss so as to have room to buy at the cheaper rate so that they don't lose customers that would end up buying most of their other supplies from the shop with the lower cerium prices.
There is a very large rare earths mine in the USA that is just about to open back up. It's a national security thing since rare earths like selenium, cerium oxide, niobium, etc are used in electronic displays, lasers, and semiconductors. I'll just end up using SnO, which I've found at a good price or grind a little longer with AlO. I certainly have not and will not buy any at the prices I've seen, especially in light of the information I've found. I just looked again and the price on ebay was $104 for a pound. This carp has gotten totally out of hand and that particular seller is quite obviously gouging the heck out of whomever is desparate enough to buy from him/her.
"... It was blamed on the Chineeze ..." (sic)
That's correct. However, the initial problem was between China and Japan. Then the Chinese started making lame excuses to limit supplies and to rein in their miners to artificially drive up prices. Unfortunately for them, there is a very large amount of smuggling of rare earths out of China and their "approved" miners were losing their shirts by being undersold. Coupled with the impending reopening of the American mine (has a cool name but I forget what it is), the Chinese government has been permitting more and more exports to try to stay in business since last year and the market prices have collapsed by a good 70% since last November. I think the WTA or whatever international authority has ruled against China in the dispute, as well, since _ I think - they were taken to international court by the US and others. Not sure about that part., though.
Anyhow, the person on ebay is obviously corrupt but I would have expected rock shops' inventories to have been pretty much depleted after almost a year unless they bought many hundreds of pounds of the stuff. Wouldn't think so, at last year's prices unless the rock biz is far more lucrative than I ever imagined. The whole bit really frustrates me. I had some CeO that I think I paid like $14 - $20 or so for in late Spring last year and haven't seen any at a sane price ever since.
Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 7, 2012 17:25:30 GMT -5
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 7, 2012 17:23:23 GMT -5
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 7, 2012 2:50:35 GMT -5
Might be a - really exceptional - slab from an "Opal Butte Orbicular" nodule. Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 5, 2012 18:36:00 GMT -5
Kev - I got the offset shaft. Looks GREAT! Check is in the mail. Thanks! Rick
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Aug 25, 2012 23:09:10 GMT -5
Hey, Kev - Just dawned on me that you need my mailing address in order to send the offset shaft. I'll PM you. C-ya, Rick
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