pfish
off to a rocking start
Member since May 2011
Posts: 4
|
Post by pfish on May 7, 2011 12:00:09 GMT -5
Hi Everyone,
I'm new around here--this is my first post, though I've been lurking around for a while. I've picked up a lot of useful knowledge here so far, so I thought I'd give this a try.
I was at a rock show a while back, and saw a batch of tumbled septarian (composed of limestone, yellow calcite, and aragonite). Anyway, it looked fantastic, so I decided to give it a try and later picked up some rough.
So far, I've run them through 60/90, 120/220, and 500 grit SiC. I decided I have no idea what to try next. I'm fairly new to tumbling, and so far I've only used Cerium Oxide with harder rocks (agates mostly). I've had great results with those, but I'm really doubtful that it would work with something as soft as septarian.
Have any of you successfully tumbled soft rocks like these before, and if so can you give me some tips?
Thanks!
|
|
|
Post by Toad on May 7, 2011 12:59:14 GMT -5
I would think hand polish for those. Do you have pics of what they look like now?
|
|
|
Post by johnjsgems on May 7, 2011 14:17:22 GMT -5
I would try some really fine aluminum oxide like .3 or .5 micron. Works really well on buffs. Please post how it works if you try it. Another choice though even more expensive would be the Super Cerium. If you had a vibe I would suggest Vibra Dry.
|
|
pfish
off to a rocking start
Member since May 2011
Posts: 4
|
Post by pfish on May 7, 2011 18:14:00 GMT -5
Thanks for the replies!
Toad, I've attached a photo of some of the rocks--hope it helps. After pre-polish, I used some cerium oxide on a wet rag and was able to buff one of the rocks to a semi-gloss finish. However, using the CO in the tumbler didn't seem to do anything. In terms of hand polishing, do you think I could use a buffing wheel? If so, what kind of polishing compound would you recommend?
John, I'm using a rotary tumbler. Is super cerium one of those really fine optical grade cerium oxides? I've done a bit of looking around, but it seems that not all sellers are specific about the particle size/grade of their compounds. Would I need to use a finer pre-polish before trying something like that?
Thanks again!
|
|
pfish
off to a rocking start
Member since May 2011
Posts: 4
|
Post by pfish on May 7, 2011 18:14:34 GMT -5
Okay, here's try #2 at including that picture...
|
|
|
Post by Toad on May 7, 2011 18:25:47 GMT -5
Those held together very well. Little to no undercutting. Nicely done.
|
|
|
Post by susand24224 on May 7, 2011 18:55:43 GMT -5
I've never tumbled those, but given that they are soft, I would do a run in 1000 prior to polishing.
Susan
|
|
|
Post by johnjsgems on May 7, 2011 20:59:54 GMT -5
Super or "French Cerium" is white and much finer than optical grade. It went really crazy high last fall. PM me a shipping address and I'll send you a sample of a really good aluminum oxide. Let me know how big your drums are too.
|
|
|
Post by johnjsgems on May 7, 2011 21:03:33 GMT -5
Yes on a pre- polish. I'll send a little Tripoli also. Tripoli is a great pre-polish for softer stones and cheap too. Your 500F is really a fine sanding, not pre-polish.
|
|
pfish
off to a rocking start
Member since May 2011
Posts: 4
|
Post by pfish on May 7, 2011 22:41:45 GMT -5
Thanks for the input everyone; this is more help than I could have hoped for.
Toad--Thanks, it's probably more dumb luck than anything else.
John--(PM sent) Thanks for getting back to me. I wouldn't have even known to look for super cerium. Is there a mean particle size associated with this stuff? As I mentioned before, I've had a hard time finding an objective measure of the different ceriums and their relative quality or properties.
Susan and John--It's good to know that 500F isn't really a pre-polish. I guess it's only worked for me so far since I've been polishing such hard stuff. Along that vein (pun intended), what's the difference between using some 1000 grit versus Tripoli? Or maybe it would be better to ask about the relative advantages and disadvantages of the two? I realize this may have been discussed here before, so I don't mean to retread old ground too much.
Thanks!
|
|
|
Post by susand24224 on May 7, 2011 23:49:14 GMT -5
I haven't used tripoli much, but Connrock swears by it and he is a very good tumbler. There are a few other experienced tumblers on the board who likewise swear by it. On the few occasions when I have added it, I haven't seen much difference in quality of tumble, but I don't recall ever using it on softer rocks. By all means, try it and see what happens!
Also, some softer rocks often take more than a week to polish--I've gone up to three weeks.
Susan (who is making mental note to try tripoli on softer rocks)
|
|
|
Post by Jack ( Yorkshire) on May 8, 2011 2:19:09 GMT -5
Hi I use Tripoli in the "Conrorck" method
I have just done a batch that had some hardish rocks from a chalky beach and was supprised how well they shined up
I burnished/Wash for 18 hours after 600 G , Then on to the 1000G for 48 hours then in with the Tripoly for 24 hours (NO wash ) then added the TO No wash all in a Lot"O" for another 24 to 36 hours
Came out a treat sorry no photo
Jack Yorkshire uk
Ps Welcome to RTH also
|
|
drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
Member since May 2008
Posts: 1,581
|
Post by drjo on May 8, 2011 9:29:23 GMT -5
Welcome!!
Nobody's mentions padding yet.
With the soft stuff I'd use alot of plastic pellets with the polish to stop the banging around.
Keep up the good work and start a notebook (if you haven't) on your tumbling technics so you know what went right and what went south.
Dr Joe
.
|
|
stefan
Cave Dweller
Member since January 2005
Posts: 14,095
|
Post by stefan on May 9, 2011 8:33:23 GMT -5
Tripoli works good on softer stuff (as well as harder stuff) there are a few websites that give particle sizes- but like you have found out- it is hard to get info from the manufacturer. For softer rocks I like to run tripoli with pellets for 2 weeks, then use Tin Oxide with pellets for 2 Weeks.
|
|
charles kuchar
spending too much on rocks
getting ready for the second coming
Member since November 2010
Posts: 300
|
Post by charles kuchar on May 15, 2011 20:01:28 GMT -5
i will try to remember that tripoli and tin oxide. the tumbling expert in our rock club says he quite using his vibe to polish and uses his tumblers instead. i just did three weeks of tripoli and now am doing three weeks of ao polish. i liked the slabs after three weeks of the tripoli. these are all agate and jasper with a couple of stones of quartz and opal. i want to try your method then for the softer stones like flourite. charlie
|
|