Today, I got a little bit of shop time in. I stopped by Home Depot to grab some plant stuff for the wife, and remembered that I needed a bag of perlite while I was there. Snagged one on the way out.
When I got home, I hung up the stag horn fern that she'd gotten recently, then got busy.
I have some chilled cast iron scrap that I'd like to turn into something useful. Unfortunately, the only thing that seems to cut it is a grinding disc, and that's not my idea of a fun project. Sorta hard to hold good tolerances with an angle grinder, too. So, I need to heat the crap out of it, and let it cool. I don't like running the big furnace for that, as it drinks propane like soda on a hot day, and my hobby funds are severely depleted. Used my last $5 on a bag of perlite.
I already had fireplace cement on-hand (purchased in Tennessee when we visited, it isn't available in FL apparently...)
Yeah, it's got 'miracle grow' in it. I'll stand upwind when I get some heat on it.
I drilled a hole in the coffee can, then used a nibbler to enlarge it. No fancy templates for this, it's a quick-n-dirty job. Gotta stay hydrated too.
Some elbow grease and two pairs of nitrile gloves later, I've mixed up enough refractory. You'll use a surprising amount of perlite in this. Some of it gets pulverized, but eventually it'll get mixed in good. A few splashes of water go a long way in making the cement a lot more mixable. Not too much water, though. It should be the consistency of thick, sticky dough. I'll pass on the taste test though.
I didn't get any pictures of ramming the coffee can up with the stuff. Mostly because it's incredibly messy, and I didn't want to chance getting smears of this indelible goop on my tablet. I used my hands to ram the mix in good, and a piece of 1" conduit cut at an angle on the end (around 30-40 degrees, I just eyeballed it, it isn't critical) was put in place to serve as the tuyere. Tuere. Teuyeyweir.....
The pipe the burner goes in.
After getting the bottom rammed in up to the level of the pipe the burner goes in, I inserted the pipe, eyeballed it to the appropriate wall thickness I wanted, and resumed packing the stuff in. A half inch more in the bottom, forming a shallow depression, and I began packing it up the sides. Once I had a nearly uniform thickness, I shoved a plastic container into the middle and rammed around it with a wooden dowel. Filled in the newly created voids, and repeated until it was full. Removed the plastic container, and smoothed the sides a little bit.
I stuck a MAPP gas torch in the pipe the burner goes in, with barely a flame on it, and put a piece of plate steel over the top. Let that run for 15-20 minutes to get some heat into the thing, then killed the torch and covered the hole in the plate to keep the heat in. I do not recommend firing this mix up to operating temperature immediately, but I wanted the bore to get a little crispy so it wouldn't slump.
It's a 3 lb coffee can, maybe a 3-3½" cavity in the middle.
I need to fabricate a little baby burner for this thing. I have a 3/4" venturi burner for the regular foundry, but that's *way* overkill for this thing. I think a 1/4" burner or so will work just fine. Don't scoff at a 1/4" burner, either. It ain't no little Benzomatic torch....
So, by this weekend, it should be cured enough that I can use it to soften up that dang chilled cast iron, provided I can knock together the burner for it. Gotta go dig through my scrap and see what's on-hand. I think I have the fittings and materials I need for it. I know, everybody's gonna want pictures. I'll try to remember to get some while I'm working.
So far, I have about $15 into this tiny little furnace. It's just the ticket to melt a teacup sized crucible of aluminum.
Spent the balance of Friday removing the old Acu-rite Unit and scales, cleaning the milling machine, and making up slotted brackets. Saturday was spent installing. Today I will fit a few aluminum angle guards over the scales.
