|
|
Post by helens on Feb 15, 2012 23:08:14 GMT -5
If I want to preserve the natural beauty of a slice or side of a rock, to see it always 'wet'... what is the best way to do this?
Start hand polishing at 600 to 1000 to 1500 to CO? Or is there a better method?
Thanks:)
Helen
|
|
adrian65
Cave Dweller 
Arch to golden memories and to great friends.
Member since February 2007
Posts: 10,790
|
Post by adrian65 on Feb 15, 2012 23:51:45 GMT -5
Helen, I share your taste for rock specimens. In my opinion, many rocks deserve to stay as they are found, with a part of their surface (corrected and) polished.
But I haven't encountered yet a stone which is so smooth to start with 600. Even the river smoothed rocks have tiny pores and irregularities on their surface, which are only outlined with 600. To get rid of them you should start with 200 or 400 at least.
Adrian
|
|
|
|
Post by helens on Feb 16, 2012 0:33:44 GMT -5
So if you don't have a grinder, start with 200 grit, then 600, then 1000, then 1500, then AO?
|
|
|
|
Post by paulshiroma on Feb 16, 2012 1:05:54 GMT -5
I'm with you on this Adrian and Helen. I've always liked specimens that were polished only on one side, with the rest of the rock in its natural state. Thanks for posting the thread.
Paul
|
|
rocpup
spending too much on rocks
Pink Limb Iris
Member since March 2011
Posts: 465
|
Post by rocpup on Feb 16, 2012 10:10:41 GMT -5
It sometimes depends what the rock or project is. When my wife does one of her Gem Ming Trees she sprays the base rock with clear paint to enhance the looks of the rock. But I would never do that on a cut face I wanted to show. But I plan to make a lamp shade of thin and fragile Iris slices in the near future and they would be difficult to polish and I will explore ideas to present them. Don
|
|
hulagrub
spending too much on rocks
Member since October 2009
Posts: 256
|
Post by hulagrub on Feb 16, 2012 18:53:29 GMT -5
I have used my Raytech vibrating lap, for many specimens. Depending on how good, the face cut is, it can take anywhere from four to ten days. I would not ever use a sander without water, we have an elderly club member who is on oxygen because of dry grinding. They now sell those hand grinders that hook up to a hose, and from the work I have seen, they can polish flat cuts and irregular surfaces.
|
|
|
|
Post by helens on Feb 16, 2012 20:33:28 GMT -5
Dave.... did I read that right? You said 4 to 10 DAYS to polish 1 little stone using a lap grinder? OUCH. Maybe I'll take what I want polished to the rock club and do them there. The problem with that is, they are only open 2 days a week for 3 hours each. So I can't get much done at a time. That's why I was thinking a hand sanding solution. I have a dremel, and lots of grits... but when I tried it, it took forever and I couldn't tell if I was getting anywhere (unlike opals which are FAST). So I wondered if there was a faster way. I guess the faster way is to buy a real polisher/grinder cabbing machine:P.
|
|
hulagrub
spending too much on rocks
Member since October 2009
Posts: 256
|
Post by hulagrub on Feb 18, 2012 22:00:16 GMT -5
Helen I load that 15 incher up, and just try to use similar hardness and size of stone. Cleaning the rocks up between grits, is the pain in the butt deal. Got a Mystic spot spray gun and I use that and on lots of different rocks. My wife is a wire bender and the gun really cleans up all those crevices in druzy and hard to reach spots. The bad part is the gun will bore a hole thru your finger in a heart beat!
|
|
|
|
Post by helens on Feb 18, 2012 23:46:34 GMT -5
Ahh. Thanks Dave:). I originally bought the vibrating tumbler thinking I could preshape cabs with the dremel, then finish the polish with the tumbler. That's not working out so well, dremel doesn't 'shape' hard stones very fast, and tumbler will pit undercutting stones:(. So I guess the best way is the old way... cut on saw, grind on cabbing machine. Drats!!
|
|
sticksinstones
starting to spend too much on rocks
Member since February 2012
Posts: 117
|
Post by sticksinstones on Feb 19, 2012 1:09:53 GMT -5
How large are the pieces you want to turn into specimens? You could use sandpaper backed with a board and rub the stone over it, but it would take a lot of iterations on all but the smallest stones. And I'd start with 100 grit silicon carbide paper as a first step - anything else will take forever.
But if you really appreciate this sort of presentation, you can do a LOT with a simple arbor and an expanding 8" drum. I've done everything from walnut sized agates to bookends on a drum that size. You change sand paper belts just by stopping the wheel and sliding one off and the other on in a few seconds. It's really versatile and you can produce amazing specimens this way. I just posted a note in another forum about the technique. You do want to wear a dust mask and do it somewhere where you can wash away the dust (it's not just the airborne stuff that's bad for you), but a spray bottle sprayed frequently on the sand paper will cut the dust down pretty well. After sanding you need a leather or wool covered polishing wheel for final polish but you can produce a mirror polished specimen from an (oil free) cut face in just a few short minutes with this simple tool.
|
|
|
|
Post by helens on Feb 19, 2012 4:26:00 GMT -5
Thanks stickinstones:). I'll look into an arbor too. My biggest problem is space... I can't stuff more big equipment in... not if I want some room for rocks:P.
|
|
hulagrub
spending too much on rocks
Member since October 2009
Posts: 256
|
Post by hulagrub on Feb 19, 2012 20:07:28 GMT -5
Helen, whatever you do, do not dry sand or grind any rock!
|
|
|
|
Post by helens on Feb 19, 2012 20:37:04 GMT -5
Dave... funny you should say that:). The other day when my husband helped me test out the tile saw, the water pump on it kept going in and out. So we did 1 cut 'dry'. Since then, it's been a few days, and ALL of us are having lung problems. We did this on the porch instead of the backyard, so every time we open the back door, we get a whiff of that dust still.
I am not going NEAR that tile saw til I get a new water pump (which is ordered and on the way)... AND I'm dragging it out to the back yard where the dust isn't 'enclosed'. I do have dust masks for working with glass powder, but who would have thought that just a few minutes running the saw dry would have such an impact? I can't even imagine breathing CLOUDS of that dust... that would really be hospital time!!
|
|
sticksinstones
starting to spend too much on rocks
Member since February 2012
Posts: 117
|
Post by sticksinstones on Feb 19, 2012 21:07:35 GMT -5
Helen, whatever you do, do not dry sand or grind any rock! That's probably over stating the hazards a bit. They are real and they are deadly, but silicosis results from long term exposure to rock dust. Virtually everyone I know that produces large quantities of lapidary specimens (and I know most of them) do so with dry sanders. Proper safety equipment is the key. A HEPA filter on a respirator doesn't cost much and will protect your lungs from the dust. As I do this very frequently I'd love to see anything more specific than just the general alarm. Most studies I have seen published on the risks have involved people in construction and mining. Lapidary is a little too much of a niche to have a lot of scientific focus on any specific risks there but like I said - I'm in that group and if there's info I should know about I'd definitely be interested in reviewing it. |
|
|
|
Post by deb193redux on Feb 19, 2012 22:40:55 GMT -5
a good vacuum system helps a lot. I knew a guy in Oregon who made a lot of bookends dry sanding, but he had the respirator, and there was a vacuum on the sander.
other guys used a Richardson's dry sander to polish t-eggs - but it had a vacume built in too.
|
|
