36 Silicon Carbide Grit: 2lbs

My application for silicon carbide grit is a bit different from most. I was looking for an alternative to sand for use in a high temperature sand bath. In chemistry, a sand bath is where you fill a vessel with sand and apply heat to it while nestling you reaction vessel in the sand. It provides even heating and allows the heating surface (the sand itself) to conform to the shape of your reaction vessel. It has a couple of advantages, like the ability to conform to the shape of any reaction vessel, but one very prominent drawback among a few others; sand is really slow to heat up and cool down. It makes it vary hard to control temperate precisely. If you overshoot on your heating, during a reaction, it takes a long time to correct it.Silicon carbide has the potential to nicely address this drawback. Silicon carbide's thermal conductivity is pretty outstanding for what it is. The thermal conductivity of sand is ~0.25 [W/(m K)]. The thermal conductivity of silicon carbide is 120 [W/(m K)]. A huge difference. For comparisons sake, aluminum is 237. That should solve the slow heating and cooling problem. A potential drawback to silicon carbide is that it is nearly as hard as diamond. It has the potential to scratch up your glassware. Nothing is really perfect though, right?Now to the important part of the review, now that you have some understanding of the basis for my review. I was looking for a product of a course enough grit to be similar to sand; free flowing and not so fine that it has the potential to be "dusty." 36 grit seems to fit that bill. While my intended use is well below the 2730c melting point of the stuff, you can't be sure what else might be in the product. Maybe it is caked in something else that will turn into horrible vapors at 200c. This is being used for rock tumbling, I am doing something very different. To test this, I took about 7.4 grams of this stuff and dried it thoroughly in a 105c oven and about 20 minutes in a desiccator to cool down. I weighed the sample on our lab's analytical balance that is capable of reading 10ths of a milligram. I then threw the sample in an electric kiln, where it stayed for an hour between 500 and 600c (932-1112f) for an hour. After letting it cool down in the desiccator again, the sample was re-weighed. The whole purpose was to see if the product had a bunch of other things in it that would burn off during use at high temperatures and maybe cause a health hazard. On final weighing, the difference 0.0014 grams or 1.4 milligrams. That is a difference in weight of 0.02%. That's nothing; that's margin of error territory. Apparently, this seller's product is exactly what they are advertising and is pretty darn pure to boot, though other things can survive 1000 degrees fahrenheit as well. Point is I am very pleased with the product I received and it is apparently pure enough that I can use it for a very different, and more technical, purpose than the product was intended for. Also much more economical! For the 12 grit stones to be used as boiling stones inside the reaction flask, Thomas Scientific charges $141.25 for 1.1 pounds (500 grams). They overcharge just because they are selling to labs and can get away with it. This is obviously a much better and more realistic bargain. Thank you Rock Shed!

I mix this 36 grit Silicon Carbide with equal parts of 45/70 grit Silicon Carbide in 1st stage tumbler barrel for harder rough rocks (6+ mohs). Seems to help reduce overall tumble time. Quality of surface on face of tumbled rocks is excellent and by no means gouged from coarser grit.

Product and Seller are legit

Nice packaging to ensure no puncturing and so far so good for quality. I just started using this kind of course but excited- maybe help speed up phase one of my rocks

This is first time to use this product to give more star's, It is nice to find a seller that doesn't over charge !In a few days I will know if this Grit is what am looking for !

as described

Consistent sized and well packaged. Didn't feel concerned about leaks with how thick the plastic was.