Black Sand

scioly2012
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Black Sand

Postby scioly2012 » Wed Sep 13, 2017 10:20 pm

Hi! I'm looking for the black sand that is often used at higher-level tournaments (it was used at 2017 nats and I believe it was also used at the MI state tournament). It does not produce those sand-clouds when its being poured. Does anyone know what kind of sand that is and where I can find it? (When I search "black sand" I find many results for different things)

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Re: Black Sand

Postby retired1 » Wed Sep 13, 2017 10:41 pm

It is not "sand". It is silicon carbide . You will have to look around a bit to find small quantities as it is normally sold in large bags or drums.
You might also search under blast media.

scioly2012
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Re: Black Sand

Postby scioly2012 » Wed Sep 13, 2017 11:15 pm

Thanks!

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Re: Black Sand

Postby cool hand luke » Thu Sep 14, 2017 12:43 am

Look for black beauty sand blasting media.

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Re: Black Sand

Postby dholdgreve » Thu Sep 14, 2017 2:32 pm

If you have a Tractor Supply locally, they sell it. It has little to no dust in it, which, if hand loading, is a real blessing to those competing. It is usually available in 3 different grit sizes, fine, medium and... you guessed it... coarse. I'd recommend going with the coarse grit, especially if using an auto-loader, as it won't sift passed the gate valve as quickly.
Dan Holdgreve
Northmont Science Olympiad
Killer of Towers
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Re: Black Sand

Postby kinghong1970 » Fri Sep 15, 2017 1:21 pm

I've been concerned about the sand we used in our first year.
it seems with hopper or by shovel method, it creates a lot of airborne dust.

i've read up on silicon carbide and based on this info and some other quick searches...
http://nj.gov/health/eoh/rtkweb/documents/fs/1658.pdf

i did not want the kids to be exposed to it.

we purchased 2 boxes of "safe sand" from lakeshore
http://www.lakeshorelearning.com/produc ... NgQAvD_BwE

still having the kids use a mask while loading the bucket.

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Re: Black Sand

Postby Balsa Man » Fri Sep 15, 2017 5:25 pm

kinghong1970 wrote:I've been concerned about the sand we used in our first year.
it seems with hopper or by shovel method, it creates a lot of airborne dust.

i've read up on silicon carbide and based on this info and some other quick searches...
http://nj.gov/health/eoh/rtkweb/documents/fs/1658.pdf

i did not want the kids to be exposed to it.

we purchased 2 boxes of "safe sand" from lakeshore
http://www.lakeshorelearning.com/produc ... p4CQkyrCU- tzrU0udXnlPhBKNNGC8QE6bc_SviY9ZDCxoCiNgQAvD_BwE

still having the kids use a mask while loading the bucket.


Just some perspective:
Being aware of inhalation hazards posed by dust (when... sand-like material falls into the load bucket), and minimizing them is very appropriate. But it is important to understand that both silicon carbide and sand (silicon dioxide, SiO2, "silica, quartz") represent similar hazards/health risks, adverse exposure risks, and both are regulated as hazardous materials in the workplace. SiO2 is actually classified as a higher health risk because it is classified as a known carcinogen (vs silicon carbide classified as a possible carcinogen).

Here's the NJ Government warning sheet on it (to compare with the silicon carbide one); similar allowed/recommended workplace exposures,
http://nj.gov/health/eoh/rtkweb/documents/fs/1660.pdf

In doing risk assessment, its important to understand you need to look at concentration of exposure and duration of exposure.. Exposure/risk is based on 'dose', the concentration, times the exposure time, The OSHA permissible exposure limits (PELs) are set for allowable concentrations in a worker's breathing zone for 8 hrs of continuous exposure; the NIOSH and ACGIH 'recommended' exposure limits are set for 10 hrs of continuous exposure. At a tower/bridge/boom loading, the 'bucket holder' student is not going to be in a position to be respiring dust from 'sand' loading for much more than a minute. So at whatever air concentration, they're getting 1/480th of what a worker would get over an 8 hr shift.

Having done some industrial hygiene air monitoring for airborne dust, and sand blasting with silicon carbide, and having watched many tower, bridge, boom loadings at S.O. events over 10+ years, my... observations are, if you're using really "dirty" sand (poorly sorted, lots of fines among the larger grains), you might be approaching concentrations that would be of concern for an 8hr exposure within a foot , maybe a foot and a half of the bucket. With well sorted/clean/washed sand, very minimal dust, well below levels of concern. With silicon carbide, particularly the larger particle size dholdgreve recommended, virtually no dust, well below levels of concern.

Having said this, I need to say, I am not providing this information/discussion as a formal expert opinion, and readers should not rely on it to assess potential exposure levels and associated health risks. If any coach, student, parent , event supervisor (or person affiliated with Science Olympiad), they should have potential exposures evaluated by a properly qualified expert (e.g, Certified Industrial Hygienist - CIH)

Hopes this helps.
Len Joeris
Fort Collins, CO

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Re: Black Sand

Postby retired1 » Fri Sep 15, 2017 6:20 pm

Silicon is the perceived bad guy by the medical profession--Silicosis. Any sand breaks down into dust faster than most would believe
.
Silicon carbide is a "carbide" and breaks down much slower, so it is safer to use. As Len said, pre washing it will help a lot. Another option would be to air sift it by slowly dropping it to a tarp in front of a box fan. Nearly all of the tiny fines will be blown away, especially if you do it twice.

Another option--NO silicon! A common blast media is aluminum oxide. It does not break down any where near as fast as sand. There are several colors-grades- and white is by far the best. For auto feeders, 80 grit size would work well. 16 would be a problem as it is quite large.

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Re: Black Sand

Postby kinghong1970 » Mon Sep 18, 2017 2:12 pm

thank you both for your detailed responses.

first year, i used a bag of sand... "play sand" they call it... and there i was in the basement, shop vac on hand and scooping sand from one bucket to another, trying to clean the fine dust... still did not help. like you guys said, it just seem to break down and keeps on creating dust.

i'll look into aluminum oxide in more depth as well.

thanks again.

Al

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Re: Black Sand

Postby dholdgreve » Tue Sep 19, 2017 1:00 pm

...How far we have progressed... I went to competition with my Son many years ago near one of the great lakes... The sand used for Boomilever was literally right off the lake shore. There was no dust, because it was still soaking wet. It was so wet that every scoop hit the fill bucket with a thud! There were enough roots in it to grow potatoes! :)
Dan Holdgreve
Northmont Science Olympiad
Killer of Towers
Buster of Crime


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