First time tumbler

I have my first batch of PBRs (pretty beach rocks) from Lake Superior
in the tumbler at the pre-polish stage. They have been there about a
week. Most of them look great, but some of the flatter, more oblong
ones look good on the flat sides, but kind of dull on the edges.

I don't plan on putting a final polish on these as I want them to have
a more natural look. Any idea how I can get the edges to match the
sides? Should I just leave them in the pre-polish a little longer?

Many thanks,

Dave

It is normal that flat pieces don't "polish" evenly but instead the edges
get the heavier erosion. The solution is to put a LOT of more rounded/uneven
stones in with the flats. When loading the tumbler put a layer of flats,
then at least twice the thickness of unevens, another layer of flats, etc.
until the barrel is loaded. The fuller the barrel the better the result. The
unevens should vary in size from about 1/2 the size of the flat/slabs down
to 1/4 inch or so. The tiny 1/4 inchers may completely wear away to nothing
as you proceed.

If you are working Agate note that in the "coarse" stage you may have to
add grit 2 or more times to get a good rounding/smoothing job done. Same
with "medium" and "fine/prepolish" because Agate is harder than hell on the
grit and the process breaks it down before it has done all it needs to do.
My last jug of Agate took 3 weeks and 3 adds ( one add, tumble a week,
check, grit broke down, add more grit - not new slurry just add grit to
existing slurry- etc. until it had smoothed the rock ) in the coarse stage
then 2 weeks and 2 adds in the medium stage then 2 weeks and 2 adds in
prepolish stage then 10 days in Chrome Oxide and 1 day in burnishing
solution to clear all the green Chrome off. They can't be distinguished to
be either wet or dry from a distance of 3 feet. You have to feel them to
tell they are dry.

Haven't yet loaded another batch. Have 7 buckets of nodules to do. 35
gallons of Agate. 12 lbs at a time.

--


Don Thompson

Ex ROMAD


"WebKatz" wrote in message
...
I have my first batch of PBRs (pretty beach rocks) from Lake Superior
in the tumbler at the pre-polish stage. They have been there about a
week. Most of them look great, but some of the flatter, more oblong
ones look good on the flat sides, but kind of dull on the edges.

I don't plan on putting a final polish on these as I want them to have
a more natural look. Any idea how I can get the edges to match the
sides? Should I just leave them in the pre-polish a little longer?

Many thanks,

Dave