rykk
spending too much on rocks
Member since September 2011
Posts: 428
|
Post by rykk on Apr 8, 2012 0:04:14 GMT -5
Hi, all. I've been having trouble getting a smooth finish on some agate nodules. My normal (vibratory lap) sequence is 120g - 220g - 500 or 600 grit - Cerium or Tin Oxide and the rocks are, typically, pretty large. Anyhow, I was having trouble getting a smooth finish on Montana agate slabs so I tried adding 14-16 hours with some 1000g Aluminum Oxide grit before the polish stage. Seemed to work on some but not so great on other agates like Agua Nueva. They're shiny, but have a lot of lines in them like maybe they've undercut between the bands. Saw this on some Crazy Lace that i didn't run in the 1000grit but had polished with Tin Oxide where each of the hundreds of agate bands was sorta outlined..
Maybe should have taken the back to 600grit to smooth them first rather than just dumping them back to the 1000g AlO, but it's got me wondering: Even though they might be the same mesh, are some grinding/polishing media more "aggressive" than others? ie: Is 1000g Aluminum Oxide a "harder" material than Silicon Carbide 1000grit? And is Tin Oxide more aggressive than Cerium or Aluminum Oxide?
Hard to find any really detailed info on the web about what polish is best for which rocks... and trial n' error using oxide polishes could get REALLY expensive and time-consuming.
Thanks, Rick
|
|
jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
|
Post by jspencer on Apr 8, 2012 22:40:36 GMT -5
I use the vibe in pretty much the same sequence as you do. I start with 220 for 3-5 days. Longer than many folks do I know. Then I like to use a 400-1000 mix I have. Or I might use some 600 for good hard rocks. 3 days in that stage usually. Then some AO prepolish for 2 days before polishing with Raybrite A. It is a great all around polish but has gotten expensive. I tried some cheap AO polish but it didn`t shine anything so I use it for a prepolish. Cerium oxide is also great but also expensive. There is a product called vibra-dri made for vibes that is a mix with walnut shell and other natural ingredients that can be bought in as high as 100,000 grit. When you are done just store it and re-use it. I know others have a favorite polish they use also that will differ from my choice but I have never failed to get a great shine. Except when I varied my loads in hardness too much and undercut the softer ones. You will find your own go to polish and routine that works, don`t get discouraged. Best of luck to ya!
|
|
|
Post by johnjsgems on Apr 9, 2012 8:23:32 GMT -5
Vibra Dry is a great product but for vibrating tumblers. He asked about vibrating laps. As I understand it, the main difference between aluminum and SC grit is SC breaks down but remains sharp so becomes finer grit where aluminum breaks down and is finished. Even though aluminum is generally less expensive I think SC would be more cost effective as it becomes finer and finer. Covington has a good polish chart on their web site that shows best polish for different rocks but most vibe lap people insist tin oxide is best polish. I used cerium with mostly good results and I'm guessing the .3 micron aluminum oxides would work well.
|
|
rykk
spending too much on rocks
Member since September 2011
Posts: 428
|
Post by rykk on Apr 9, 2012 14:39:25 GMT -5
Thanks, both of you.
John - So can I assume, then, that AlO grit would require more frequent recharging than SiO? And that reusing a pad charged with AlO polish wouldn't be doable like reusing a pad (stored wet in plastic bag) charged with Cerium or Tin oxides is reputed to be?
I was getting great results last Fall/Winter but have lately been having trouble. Don't know if it was a "bad" batch of Tin Oxide - maybe not as fine - or what. Go figure; I now have the "correct" rubber balls and the correct motor with the same springs I've had all along and now the thing is out of whack. Tried "TXP" - not good - and now I'm trying some pinkish Cerium, 1.5 micron. It seems that the cerium is slower but I am getting a shine without a lot of graininess to it but the jury is still out.
I'm now trying the golf balls that I originally used b4 I found the "real" ones for sale on ebay which are half-again as big. It does seem that the 500 grit phase is working faster but I'll need to do a 120 or 220 to really know for as sure as you can know anything in this hobby.
I haven't found anywhere in town that has wool carpet or at least a remnant to use for a pad in place of the Kingsley ones. Does boat carpet really not work??? *That* I can find but the house carpet folks tend to leave all remnants with the customers. Thanks, Rick
|
|
jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
|
Post by jspencer on Apr 9, 2012 21:42:01 GMT -5
Oops.......I guess I did read it wrong. ;D But best of luck stays with you.
|
|
|
Post by johnjsgems on Apr 9, 2012 23:06:36 GMT -5
You should be able to reuse the aluminum oxide polish pad. What micron rating is the aluminum? TXP is 3-4 and works great in rotary tumblers. For the vibe lap you need something much finer like .5 or better yet .3 micron.
|
|
rykk
spending too much on rocks
Member since September 2011
Posts: 428
|
Post by rykk on Apr 10, 2012 16:06:57 GMT -5
"...For the vibe lap you need something much finer like .5 or better yet .3 micron...."
Aaaaahh - so THAT's why TXP wasn't so hot. I had been looking for something to use in lieu of tin or cerium, for which imo we are being price gouged obscenely for (the restrictions China put on rare earths came about in an economic argument with Japan and ONLY Japan was cut off - not the US/world!). I'll look into prices for finer AlO, then. Hopefully much cheaper than tin/cerium. If I can't find some sort of polish pad that will last - ie: maintain its thickness more than 2-3 batches of t-eggs/agate nodules/weighted slabs - so that I don't have to buy polish so often to recharge the new pad with, I may either just pack away the ton of rocks I've bought and wait for either the prices to come back to where they belong or try to sell them - most likely at a loss.
Anyhow, sorry for the rant. So, with AlO polish of less than a micron, I can charge the pad up, do a couple batches, store it safely, and then reuse the already charged pad again, right? Understanding that I'd still have to add a little fresh polish occasionally but certainly not a half a pound? Thanks, Rick
|
|
|
Post by johnjsgems on Apr 11, 2012 8:40:17 GMT -5
That's right. I have .3 on my web site (OMG2) for 19.95 per lb. but sell it to RTH members for $18. That is a pretty normal price I think but I don't remember who else sells it. There is a surprisingly big difference between .5 and .3 micron in performance.
|
|
rykk
spending too much on rocks
Member since September 2011
Posts: 428
|
Post by rykk on Apr 21, 2012 18:52:20 GMT -5
John - Went to jsgems and was going to buy some of this. Found there was a $20 minimum order set by the Checkout software; no biggie. But - Is there any other shipping method than "Weight Based Shipping" available? $18 is pretty steep for something that would fit into a USPS small flat-rate box. Was hoping to try this polish out but the very high shipping brings the cost right back to where cerium and tin are... Thanks, Rick
|
|
|
Post by johnjsgems on Apr 21, 2012 19:40:38 GMT -5
Rick, just e-mail me or PM me. I actually ship everything I can by Priority Mail so shipping is almost always less than the web calculates. I manually process orders so I can correct shipping charges before charging anyone. I may have to lower the minimum. I put it on after getting a bunch of $9.95 and $11.95 orders.
|
|
rykk
spending too much on rocks
Member since September 2011
Posts: 428
|
Post by rykk on Apr 22, 2012 0:56:09 GMT -5
When I read stuff on the home page more closely, I pretty much figured that it was a limitation of the website/checkout software as far as the shipping charge. Figured I'd answer your post here so that, if anyone else had shied away, they would read it here and learn it wasn't the real shipping charge.
LOL - Dang, I missed the min. by 5 cents! I reckon I could always use a leather spinner lap pad, too, to replace the one I got somewhere else last year that I tossed in the ye olde circular file in disgust...... because, as I learned later, I had be trying to polish with it...... using the wrong side! What a noob. :-) Thanks, Rick
|
|
|
Post by johnjsgems on Apr 22, 2012 7:10:55 GMT -5
You can actually use leather pads either way. I have commercial cutters that swear by smooth side out for polish but most use rough side out for polish, smooth side for diamond. I'll delete the leather pad if you really don't want it.
Shipping is a real problem. Most of my equipment manufacturers that drop ship big ticket items are in Southern CA and use either FedEx or UPS Ground. A 25 lb. item shipped within CA costs about $20. Same item to NY is about $40. I use a shipping table based on UPS retail to cover to East Coast but loose money (a little bit) to South Florida. From Mid West charges are too high and way high to CA or AZ or West Coast. I manually process all orders and the website really only captures customer info securely. I put notices all over about shipping but it is a lot like those instructions that come with everything that nobody reads. With Priority Mail I can send most small orders very reasonably with often times less than the $10.85 MFRB charge. I ship from wherever I am in the country when on a show circuit to further confuse things. Your order will ship from Dripping Springs, TX. USPS is more consistent than UPS but wouldn't work for anything too big or too heavy.
|
|