When I worked I did HVAC repairs,, so I had some kaowool wet pak left over from a job. This is used in oil furnaces for the fire box insulation. It is about 9/16" thick and comes pre wetted with a rididizer in a plastic bag and is preshaped and cut for specific furnaces by model number. I cut to size for both the coffee can and the propane canister and pressed it into place. I allowed a couple of days for the kaowool to dry some then ran the burner on low until pretty dry. Once it was dry I painted on a layer of refractory about 1/4" thick and fired the little furnaces up to yellow heat (about 1200 deg F) after they were cool I painted on the ITC100 allowed to dry then fired with a crucible and charge of Merlin's Gold Jewelers bronze. I was able to melt the bronze in about 20 minutes although I wasn't running the burner at full on. The burners are sized down Mikey burners. I'm very happy with the performance and ability to melt small charges in these mini furnaces. I have several sizes of furnaces and crucibles and probably the ones I use most are the coffee can and the 30# size freon / helium size bottle.
Kaowool is fairly cheap and easy to work with and can be bought at pottery supply or online at budget casting, etc. Any size furnace can be built with a little thought and patience!
Cheers Wonk
--- In gingery_machines@yahoogroups.com, Jim Ash <ashcan@...> wrote:
>
> Wonk -
>
> I just took a look at the LP bottle and coffee can furnaces. Pretty cool. What kind of refractory mix did you use for these, and how how thick? Would you do them each again and what would you do differently? Is the coffee can burner just a scaled-down cousin of the larger one, or did you have to change the proportions? And I noticed mapp gas in the one photo. Do you prefer it over LP or this application? I use it here for outside work when the temps are so cold that a regular LP plumber's bottle will ice up, but the thought just never crossed-my mind to use it for a small foundry.
>
> Jim Ash
>
> -----Original Message-----
> From: Wonk
> Sent: Jul 20, 2011 4:48 PM
> To: gingery_machines@yahoogroups.com
> Subject: [gingery_machines] Re: Build a Gingery Lathe
>
>
>
>
>
> Rick,
>
> It would be far easier to find a metal container and insulate it with kaowool if all you wanted to melt was ZA-12. Take a look at some of my small jewelers furnaces that I have made in coffee cans or toss away propane bottles. I used a thin layer of refractory as a hot face and ITC100 in mine as I wanted to melt up to bronze temps.
>
> See my photos in the tiwonk folder in the photos
>
> Wonk
>
> --- In gingery_machines@yahoogroups.com, Rick Sparber <rgsparber@> wrote:
> >
> > CT2,
> >
> > I can see value in a small capacity, fast heat furnace that can do only ZA12. Maybe make it from lashed together firebricks. It would sure be handy for those small, quick jobs.
> >
> > Rick
> > Rick.Sparber.org
> >
>
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