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[DPRG] Making Metal

Subject: [DPRG] Making Metal
From: RoboVac robovac at mninter.net
Date: Wed Oct 18 12:17:36 CDT 2000

An important safety tip is to wear thick leather work boots.  Ideally with
leather pants and leather shields over the boots..  Make sure any spilled
metal will not go into your shoes, but will run off instead.  Dropping or
spilling a crucible of molten metal can make some very horrible injuries.
Using smaller amounts of molten metal also helps prevent injuries

William Crolley

----- Original Message -----
>From: Eric Yundt <eric at facetcorp.com>
To: Dallas Personal Robotics Group <dprglist at dprg.org>
Sent: Wednesday, October 18, 2000 2:02 AM
Subject: [DPRG] Making Metal

> As I type this, my first ever (Aluminum) ingot is cooling down!
> For a long time I've heard how easy it is for a hobbiest to build
> a little backyard foundry and cast parts.  This afternoon while
> taking a little "honey-do, stay-at-home" vacation time I thought
> I'd give it a try...
> I scrounged up a 3-lb (actually 39 oz) coffee can, a 16 oz dog-food
> can, a couple of coat-hangers and a few bricks.  Then went shopping
> to get some "official" welder's gloves (leather gloves with an 9" or
> so cuff) and a bag of charcoal.  At the last minute I thought to get
> some sand for making a mold and reward myself with a long-handled
> pair of channel-lock pliers.  All I could find at Home Depot was
> some for-playground/concrete sand which has lots of little pebbles
> in it, but I managed to shake out most of them.
> I poked a bunch of holes in the bottom of the big can for air-flow
> and a couple of holes in the lip of the little can for a coat-hanger
> bail/handle.  The bricks were arranged on a piece of sheet metal in
> my backyard in a U-shape.  I made the "U" just big enough for the
> large can to rest by its edges and completely cover the area inside
> the "U" leaving only an air flute opening at the top of the "U".
> Then to make a mold I filled the bottom of a flower pot saucer with
> my so-so sand and poked a few pits in the sand about 1" deep and 1.5"
> in diameter.
> After "mining" 20 or so Mountain Dew cans from a nearby trash can
> I figured I was about ready to crank up YaTu Metalworks No.1.
> I halfway filled the large can with charcoal, stuck my little can
> inside it, soaked it all with starter fluid and then sparked it up.
> While the charcoal was heating up, I stomped down all my cans and
> rustled up a couple of old hair dryers to create the blast for my
> little blast furnace.  To super heat the charcoal I put my best hair
> dryer down in front of the brick "U", but after only 5 minutes or so
> its thermal shutdown kept turning it off.  Not to be stymied at this
> point, I grabbed a vacuum cleaner and with a hose stuffed in its
> exhaust port soon had a much better "blast!"
> The vacuum cleaner exhaust soon had my furnace glowing and with my
> fancy gloves and shiny pliers I started putting crushed cans into my
> dog food can crucible.  After 15 minutes or so my 1st 4 cans started
> shrinking down and then every few minutes or so I fed a couple more
> soda cans into the crucible.  I lost count, but I think I eventually
> added about 15 crushed cans into my little crucible before I gave it
> one last stir and removed it from the fierce flame.
> As I started to pour into my mold, I finally understood what "dross"
> was all about.  Probably 3/4 by volume of what I got out of my
> crucible appeared to be junk floating on top of a little pool of
> shiny liquid aluminum.  I mostly scooped it off to the side and
> dumped the rest of it into one of my sand pits.  I didn't get near
> as much pourable stuff out of it as I expected and then I noticed
> that the bottom of my poor dog food can had partially burned through.
> None-the-less, I got my first ingot -- a lovely 1/2" deep, 1 1/2" by
> 4" blob!  Plus, many ideas about how to do it better next time...
> ;-)
> --
> Eric
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