Small, easy to move around... 6 insulating fire bricks, ceramic fiber blanket & hardener, photo copy stand, small bench top router stand, 5 gal metal can, and a small stainless steel bowel for the top half.. I used a 1" ceramic fiber board as underlayment for the bricks.. Had it on hand, probably have used some blanket as substitute.. Trying to keep the heat from the router table.. The space between bricks and can were stuffed with fiber to tighten the bricks.. Having a bit of a problem with my pics..
Managed to post pics, but lost the text.. The top is lined with rigidized 1" blanket.. A few screws around the bottom, plus the bent over tabs on the bowel hold it all... The hardener locks everything in place..
That looks well done and efficient. Looks like it may have seen duty. How about a couple of pictures of the Tuyere and burner. Best, Kelly
Mytwhyt. I like that and may just borrow the lid lift method when I do my propane burner melter. Are you using this mainly for aluminum?
Al203, Don't have any good pics of the Tuyere, just an angled hole through the brick.. A little blanket stuffed along side the burner.. It doesn't extend past the brick.. I don't need a flare on the end.. The crucible I use is an empty 1lb propane canister.. Filled to the top it's only a couple pounds.. I use a kiln shelf wash inside and out of it.. I get an easy 5-6 melts with it.. I'll get a pic of what I use to pick up the canister and pour..
The second photo shows blue flames coming out of the vent, which gives the impression that most gas burning takes place there and not inside the furnace. Lifting the lid for a while might result in a 'pop' at which the flame moves inside.
That was a first time low light pic. in the shop .. I had it cranked up empty to see what it would do.. From candle to full burn it does a good job of melting aluminum.. My operation is on the small side.. Like the kid at Disney Land, I'm barely tall enough to go on this ride.. I started small and worked my way up to this... Now the damned sand molds are just too heavy to be any fun.. Thinking of selling my sterling castings on Etsy. I have a hand injection wax pot and a couple hundred rubber molds and two Kerr casting machines... Maybe for a winter project.. Found this site and now I'm just digging up bones..
After coming across this article on perlite for insulation, PERLITE/SILICATE COMPOSITES FOR HIGH TEMPERATURE INSULATION AND FORMED SHAPES---A SCHUNDLER PRODUCT GUIDE I thought I'd test it for myself.. I used a small Solo cup, perlite, and enough Sodium silicate . Not too much syrup, just enough to stick it all together, like a popcorn ball... Firmly packed in the Solo cup.. Firm, but not hard enough to crush the perlite.. After a day in the cup the cup the SS had air hardened...The coin is for size, the ten cement bricks to test for strength.. I was impressed.
What jumps out at me from that article is the thermal limit of the perlite/sodium silicate composite, it's 1200°F/650°C, that's not adequate for the main body of a foundry furnace but it might be suitable for secondary back-up insulation
What jumped out at me was, Great, moldable secondary insulation." But not a hot face alternative" Not even for aluminum.. Ceramic fiber blanket has taken the place of perlite in most applications. But FB still needs sodium silicate to harden it..
This is the type of crucible I use for aluminum in this furnace. It's an empty 1lb propane tank. The pouring tool is as simple as it gets.. There is a grove in the rod that catches on the crucible to keep it from sliding off. Before I use it I'll burn it clean and shape a slight lip to help direct the flow. It'll also get a coat of kiln shelf wash inside and out before each use.. I believe it's mostly kaolin, only costs a few pennies. 4-5 melts or more.. I checked it's volume by filling it with water to within 1.25" below the hole, 24 ounces.. I took a hint from Kelly's lift off furnace. I went for the simplest alternative I could think of, a lift off top half. Handling the crucible only one time to pour sold me right off.
