scratches on hematite
Michael & Denise Jenkins
Could someone tell me if zam aplied with a felt buffing wheel will
get scratches off of a hematite cabochon?"???? What about tripoli;
wiould it work? Never had to do this before and I'm ignorant about
lapidary skills.
Denise Jenkins <mdjenk.blkbox.com>
John Miller
Michael & Denise Jenkins wrote:
>
> Could someone tell me if zam aplied with a felt buffing wheel will
> get scratches off of a hematite cabochon?"???? What about tripoli;
> wiould it work? Never had to do this before and I'm ignorant about
> lapidary skills.
If the scratches are at all deep, you probably need to wet sand (1200)
the stone before polishing. It's usually a waste of time trying to
polish out deep scratches -- they really need to be cut away and
smoothed first. After sanding, Zam on felt would probably give a decent
polish; tripoli might, but would not be my first choice.
--
John Miller, CNE/GG/LAN Administrator
UNC Dept. of Pharmacology, CB# 7365, Chapel Hill, NC 27599
(919) 966-6966, fax (919) 966-5640, email John_...@unc.edu
Gemology & Lapidary Pages -- http://www.tradeshop.com/gems/
John Franke
mdj...@blkbox.com (Michael & Denise Jenkins) wrote:
>Could someone tell me if zam aplied with a felt buffing wheel will
>get scratches off of a hematite cabochon?"???? What about tripoli;
>wiould it work? Never had to do this before and I'm ignorant about
>lapidary skills.
It's worth a try: tripoli first, then the Zam.
Typically, hematite polishes well with cerium oxide or alumina on
cloth buffs or leather. If the tripoli/Zam doesn't work out and you
don't have access to either of these other polishes, let me know and I
will send you some via snail mail.
Hope this helps.
-John
* John and Barbara Franke *
* jfr...@gemcutter.com WA, USA *
* Facet Shoppe: Faceting/ Rough & CutGemstones *
* http://www.olympus.net/gemcutter *
Herb Lueck
Michael & Denise Jenkins wrote:
>
> Could someone tell me if zam aplied with a felt buffing wheel will
> wiould it work? Never had to do this before and I'm ignorant about
> lapidary skills.
>
> Denise Jenkins <mdjenk.blkbox.com>
Denise,
Hematite is really glorified _rust_ (it's iron oxide). It is messy to
work with and responds more like a metal, which it is, than a gemstone.
Most metals can be buffed first with tripoli, then after thorough
cleaning on another buff with Zam (intended for silver).
The preferred technique is to grind down past the scratch with a fine
abrasive (about 1,200 to 8,000 mesh) and then polish either with very
fine diamond compound (14,000 mesh or finer) or better yet, damp leather
charged with cerium oxide (.5 micron) or Linde A (aluminum oxide .3
micron).
If you cannot do it that way, buff _across_ the scratch, as this tends
to drag material off its shoulders, whereas buffing _along_ it tends to
widen and deepen it. That's why it's best to grind it down first.
-Herb Lueck
Jeweler & lapidary instructor
dpirie
I wish to build my own rock tumbler and would like to know if there is
an optimum speed for the barrels.
Can anyone help?
David P
Catherine Harrison
dpirie <dpi...@unb.ca> writes:
Sinkankas gives excellent advice in _Gemcutting: A Lapidar y's Manual_.
Optimal tumbling speed depends on the diameter of the barrel. For 6"
barrel, 35-55 rpm is what he suggests. Mine operates at around 40 rpm,
and it's working great. I built my own and am very happy with the results.
If anyone's interested, complete instructions for my tumbler, with photos,
will appear in _The Eclectic Lapidary_, Carol Bova's web e-zine, when it debuts
later this year.
Good luckwith your tumbler! I was so happy with the way minde turned out
that now I'm building a lapidary grinder/sander/polisher, and next a saw,
and after that I'm starting to plan a vibratory lap. I couldn't afford to
buy this stuff, but with salvaged parts and some time and effort, I'm well
set up.
Cate
Curt Gates
> I wish to build my own rock tumbler and would like to know if there is
> an optimum speed for the barrels.
> Can anyone help?
David, the speed depends on the diameter of the barrels and whether they
are round inside or polygons. The optimum speed is where the contents
roll steadily downhill. If the speed is too fast, the stones will cascade;
too slow, the slip back down the slope. About 30 to 34 rpm is good for
the barrels Lortone makes.
You can tilt the container at a 45 degree angle so you can see what is
happening. You might want to buy the barrels from Lortone. I used to make
them out of wood, using a table saw to cut the bevels. Sealing can be
tricky. I used three bolts and a triangular piece of metal to hold a lid
on.
Used a pair of washing machine wringers and the washing machine motor.
Lots of possibilities. E-mail me if you need more suggestions.
Curt
--
THE STONEWORKS
Wampum, Anthill Garnets, Yogo Gulch Sapphires
Beads to Banish Boredom
http://www.tiac.net/users/wampum/