Hi everyone
when I first started tumbling rocks, I wondered why you couldn't use sand
as tumbling grit instead of silicon carbide. After all, this cost me 5 dollars
for 50 pounds, and this was 83 dollars for 45 pounds. Plus you've got to pay
shipping on this, where this I can just run down to Home Depot and pick it up
so, I thought we'd try some experiments and see if we could figure out if
this is a better option, save a lot of money
you might be wondering why I bought sand when you can just go out on the
ground and pick it up
I bought it because, well two reasons. First off, it's winter, so there's snow on
the ground. And secondly, I wanted a more standardized sand
sand varies a little bit, there's some that's kind of powdery and some that's more coarse
this is Quikrete brand, so you know exactly what I'm using
so here's what I'm doing. I've got 3 barrels filled with desert jasper
I have the same number of rocks in each barrel, and each barrel weighs the same
to the nearest gram
I've already put a cup of water in each of these, and I'm going to add a cup of water
to this one
and then, this is just going to be just like this, water and rocks, nothing else
this one I'm going to put in 3 tablespoons of sand
so 1
2, 3
and then this one I've got 46/70 silicon carbide grit, which is what I would normally
use in the first stage, this is also a tablespoon, so 3 of these
and I'll put these on a tumbler for a week and we'll take them off and see how
they're looking at that time
well these have been running for a week now, so let's take a look
this is the one with just water and rocks
the slurry looks pretty watery, it is a brownish color
so something happened in there, maybe just washed the rocks, I don't know
this is the sand and water and rocks
lighter colored slurry
I'd say they look equally watery
and then this is the one with the 46/70 grit in it
and this one's lighter yet, it's kind of a greyish color, maybe there's just a little
bit of a slick on the top, maybe it's not a lot different color
I do notice, this one the rocks look like they're higher up in the barrel, and this
one looks like the rocks have settled down a little bit more
I don't know if you can tell that, but I'm thinking these might have gotten
ground down more and so they're settled in a little bit
so I'm going to go rinse these off, and we'll weigh them, and take a look at the
rocks themselves a little more closely and see if we can notice any differences
I've got everything rinsed and dried off and I think the results are pretty
interesting
the plain old water and the sand came out exactly the same, they both lost 8 grams
or 1.3% of their initial weight
and the stuff that was done in Silicon Carbide lost 47 grams, or 7.4% of it's
initial weight, so this is significantly more ground down
looking at them up close, here's a rock that hasn't been tumbled at all, so
they start out with very sharp corners on them, like this one, and those
corners have been worn off some by just plain old water
but what's interesting about the ones that were just done in water is it's got a little
shine to it, it's like it polished. There was no polish in there, but just
rubbing up against each other, they polished a little bit, I think you can see that
there
these look pretty much the same, they're still pretty sharp, but not as sharp as
the un-tumbled rocks
and then if you look at these
these are much more ground down, and neither of these have a shine on them either
these are the most dull
but, it looks a lot different than it did before. If you just look at these two
piles I think you can see a big difference in them
so another factor here besides just polishing down or grinding down is
that there's little chips left over. So when I rinsed these off, I rinsed them through
a wire mesh screen, and there's little pieces from that
there's a lot more pieces that broke off from the ones done in the sand
and
the ones in the silicon carbide are kind of similar
so, that was not weighed, I didn't weigh those when I weighed this stuff to see
how much they lost, I didn't include these little pieces because those are broken off
so when you've got a fresh piece of rock, more of this stuff's going to break off
in the first week than in following weeks just because it's sharper. So what I'm
going to do is run these for another week, and I shouldn't have as much of this stuff
left over after another week I don't think, we'll find out
so that way we can get a little more fair assessment of how much is grinding
and how much just fell off due to chips coming off
so I'm going to put these in for another week just like I did before, same amount
of grit, everything's going to be the same these little pieces won't be included
it'll just be the bigger rocks
so I'll see you again in another week!
the ones that were just done in water
these were tumbled with sand
and these were tumbled in silicon carbide
after another week of tumbling we've got some really interesting results
check out these rocks that were just tumbled in water, there was nothing
else except water and rocks in the barrel and they are getting
shinier this week than they were last week
they already had a little shine on them, but look at that
so one of the steps in rock tumbling that's often suggested is called burnishing
and burnishing is where you take the rocks after all done tumbling, you put them back
in the barrel with water and either borax
or ivory soap shavings
and then you run them for, I don't even know how long, a couple of days maybe
is what's recommended, I don't usually do it so I don't really know
and I've always kind of, I don't know, written it off as something that doesn't
really work because I've tried it a bunch of times and have never seen my rocks get
any shinier
the thing is, with the Lot-O tumbler, they come out so shiny in the first place - wow
look at that one
they come out so shiny from the Lot-O tumbler that there's not much shinier
that they can get, so for me, burnishing hasn't really done anything. But I can
now see if your rocks are coming out and they're kind of dull, well
these got really shiny even though they started out as completely rough, broken rocks
so I have a new appreciation for burnishing
if your rocks aren't coming out super good give it a shot, see what happens
these were done in the sand
and they are not shiny, they've got a little bit of a gloss to them, but not much
and they're also not worn down very much, you can still see they have pretty
sharp edges on them, as do these
so, not much is happening here with the sand
and then over here, the ones that were done in silicon carbide, they are much more
rounded
these sharp edges are still somewhat sharp, but they're rounding off more than the
other ones did
so I just- just looking at the whole pile you can see that these are more rounded
and the pile's even smaller than these are
so we still lost some little chips off them, these are the ones that were done
in the water
these were tumbled in sand, these have the most chips by far, I don't really know why
but there's that came off of there
and these were done in the silicon carbide
so, whether fewer chips came off, or if the chips just got ground down by the
silicon carbide, I don't know, but this is what was left
so, since last week, here's what we've got
this one lost 13 grams, this was just since last week, I didn't go all the way back
to the beginning
13 grams is about 2%, of the - 2.1% of the weight from last week
the ones that were done in sand lost only 6 grams, or 1%
and the ones that were done in silicon carbide lost 51 grams, or 8.6%
so why is silicon carbide so much better?
these rocks are a 7 on the Mohs scale of mineral hardness
and 7 is a pretty hard rock, that's what a lot of your jaspers and quartzes and
agates are going to be, and silicon carbide is 9, or over 9 on the Mohs scale
so you've got a much harder abrasive in here that's going to grind this away better
besides that, silicon carbide is very sharp so it's designed to grind stuff down
the ones that were done in sand
you got sand that's mostly quartz
it's going to vary
but the sand I'm using I think is mostly quartz, and quartz is also a 7 on the
Mohs scale, so you've got an abrasive that's the same hardness as the rocks, that's not
going to do much good
the sand probably got ground down to nothing by the rocks pretty quickly
in the process here
so if you're trying to save money
you can save money by doing them just in plain water and get a pretty good shine
by the looks of it, at least on these rocks
but if you're trying to get something rounded, it's going to take forever to
round them in sand
silicon carbide is going to do the job a little bit quicker, a lot quicker
and it's also going to save you some
electricity, rock tumblers don't use a whole lot of electricity, but you are going to use
a lot more if you've got to run these for 7 or 8 times longer than these do
plus you're going to get really tired of waiting
so I'd say go ahead and spend the extra money, get yourself some silicon carbide
and grind a little faster
I did another video looking at the amount of electricity that rock tumblers use, so if
you'd like to check out that video, there's a link here, and there's a link to a
playlist of videos about rock tumbling you might enjoy too, so I'll see you over
at one of those videos