The Shop > Our Shop
Working on a new tiny shop
Swarfing:
Line a container with thick straw, put your sand box inside and cover with more straw and a lid.
mattinker:
--- Quote from: JohnHaine on February 16, 2015, 02:33:16 PM ---Matt, as salt is used in molten form for heat treating, I don't actually think this can be true. Chlorine and sodium are two of the most reactive things around, it will take a lot to persuade them to dissociate.
--- End quote ---
The friend who told me about this is no longer with us so I can't ask him, he died of other, natural causes.
Salt Glazing
This process involves throwing wet salt (sodium chloride) into the heated kiln while the bisque ware is being fired. Wet salt at high temperatures decomposed to sodium and chlorine. The sodium reacts with the bisque ware to form a glaze. Large amounts of hydrogen chloride gas and possibly chlorine are also formed.
This is a quote from lower down the page.
http://www.baylor.edu/ehs/index.php?id=94374
regards, Matthew.
vtsteam:
The 50 watt Hydrokable just arrived by post and I've got it burried in my tub of greensand to give it a test. It's a good test considering the low temps right now! :borg:
vtsteam:
The test went well after about 3-1/2 hours. The sand was cool, but not cold, though there was some unmelted snow on the concrete floor of the shop, meaning subfreezing temps down at floor level. There were a few warm spots in the sand, too -- I hadn't buried the cable evenly some stuck out above the surface -- the bin is only half full of sand and the cable is 20 feet long.
Also it's dry sand right now so heat doesn't spread as easily. I didn't want to temper it with water until I had the heat cable to work with. Tough to warm up a big frozen block without some heat running through it!
I unplugged the heater. I don't want to run it overnight yet. Tomorrow morning I'll temper the sand and check how well that works with the cable. Then we'll let it freeze and find out how long it takes to thaw.
The bin is uninsulated at this point, but if needed I can add that, too. Looks good though without, so far.
vtsteam:
I tempered the sand today and it sure is great to have good molding sand again. I just really enjoy that stuff when it's right. Cable in place. Letting it freeze overnight. Tomorrow we'll see how well it defrosts.
I also cut the top off of a 30 lb propane tank -- a little taller than the usual 20 lb tank. Cleaned it out to make a new melting furnace for the tiny shop, to fit under the bench. I need it now to cast my new lathe pulley.
I was going to go against my usual grain, and actually buy the expensive stuff for refractory -- cerrablanket, and zircon rigidizer per Ironman's style small propane furnace. But U.S. BS manufacturing distribution systems struck again! :bang:
I wrote to the only company I could find here that offered zircon rigidizer, naturally you had to write to their factory sales rep to inquire where to obtain it and how expensive a pint of that stuff would be (it does come in individual pints, so I can imagine it must be pricey!).
I received a note back from sales rep. "David" today asking what my purpose was. So I replied to that, saying a small metal melting furnace, propane powered, fiber blanket refractory, about 4 square feet exposed needing rigidizer. He wrote back that I shouldn't use their product in my application. No price given, no availabiltiy info.
So I said the hell with it -- this is why I like making things from locally available materials. Otherwise you can't just do what you want to do AS AN EXPERIMENT. If you go the high tech refractory route, you gotta face a bunch of industrial salespeople of limited imagination questioning your intent and your quaiifications to obtain their product.
I can go to my local hardware store and buy a chainsaw, some Drano, and a can of acetone, and NOBODY asks me what my intent and usage are, or what my business name is. They figure I know what I want to do with it, and that's enough. They also put prices on things, instead of asking you to contact them to inquire.
For heaven's sakes how do manufacturers like this zircon outfit think that most of the industries (including their own, no doubt) begin? A vast number have begun based on an individual's ideas, and invention. Luckily their founders 100 years ago weren't blocked from obtaining small quantities of whatever they needed to make new things because they were individuals.
Anyway, I said the hell with it, went to the hardware store, bought a bag of plaster of Paris and sand, Took an 8" diameter piece of leftover Sonotube, set it as a chamber form in the cutoff propane tank, and poured a lining. Took an hour total. Materials were $19 total with some left over. I'm sure it will melt my aluminum for the pulley. Sheesh..... :doh:
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