Scott - Interesting design! I see you have the blower coming in at about a 90 degree angle to your torch (and is that a second torch opposite?) All the other ones I've seen have the gas/torch and blower component rigged together. How's that working for you? The one I'm building - stainless industrial tea container lined with kaowool coated with itc-100 - doesn't have a blower as of yet. But then, I haven't attempted a melt yet so that may need to be an addition...and if your configuration works, it may be easier with what I'm working with.
the "blower" is more bizarre than you guess :-)
First, the two "made in italy" weed burners/snow melters are venturi designs that suck air in as the propane is delivered. This also cools the nozzle. Great design.
It'll melt aluminum without adding *any* air so you don't need a whole lot *more* air to get hot enough to melt bronze.
Any stream of air aimed at gap between the base of the furnace and the pill block just lights this puppy up somethin' fierce. In the studio I have an old air nozzle that leaks bad and it supplies enough air to get to bronze melting temperatures. The leaf blower just idles a foot or less away from the base. No piping. Check the color in the throat with flash photo.
The propane venturiis are on parallel lines that are just under the inner diameter apart. Really strong swirl/mix.
I found the cylinder in a dumpster next to a laboratory refit. It's a leftover section of stainless ducting.
A friend gave me a clay covered chunk of metal that turned into the stainless leaves/blades around the top - sheared, rolled, spotwelded. The perforated stainless base is from a lab animal cage tray that got donated. Even the handles were scrounged.
Started as kaowool with coloidal silica/cerium oxide/zircon flour coating. I just "relined" it with a half gallon of expired 3000F+ alumina adhesive. Tough stuff, amazing what you can scrounge up to make a furnace :-)
Planning a melt next month to try out the new lining. Experimenting with minimalist ceramic shell and haven't got my mix right yet.
Main thought on Aluminum vs bronze melting is alum is 900 - 1200 vs bronze at around 2200 - 2300 deg F. near double the heat requires. I tried atmospheric burners and they just took too long. The controlled/forced air units that I made were cheap, rebuild-able and got the job done in a hurry with good lbs. of propane used to melt lbs of bronze. I got a good swirl just by angling the burner to the furnace wall. I used high temp ceramic bricks to make a crucible base (one brick high) with the burners right at ground level.
I like a appreciate you ability to "fine" usable materials. When I started in Anderson Valley (NW of you about 1.5 hours on hwy 128) there were no scrounge locations available. I am very glad you have and are making use of such these days.
web site: http://www.MLCE.net and ctmandalas.com
I just got a new optical pyrometer, I'll check the temps with and without added air next time I fire it up.
3000F for under $200 - with lasers! WooHoo
Venturi only won't melt bronze but it'll get close.
Where did you find an optical pyrometer for under $200? I really want one for my forge and that's within my price range.
found it by accident, was just looking for a regular IR thermometer.
they also have 4000F for $400 :-)
Huge jump from my ancient Pyro
trying to see through and match colors compared to point and shoot