Re: [multimachine] metal casting
- Pat wrote:
> Just re-found this good resourceMy favorite is:
> ... http://www.alloyavenue.com/vb/forum.php
In the fall of '09, "Rick-o-Matic" (Rick C, who gives a metal
casting demo at NAMES Expo in SE Michigan every year)
organized an assembly line, where we all got together
over two weekends to make his "5 gal bucket with a custom lid"
aluminum metal casting furnace. It uses the Oliver propane burner,
shown above. Something like 20 or 50 furnaces were knocked
out over those two weekend sessions
The first weekend was a full day to make all of our furnaces
and lids. Furnaces were the 5 gal bucket with refractory,
and the lid was a loop of flashing, with refrectory in the center,
and a paper form to make the hole. We then set them aside for
a week or two to dry. The second day session was lid final
assembly, burner build, and "gentle first firing" to burn out the
paper forms and dry the refractory out over a few hours.
BTW... Rick proved that putting a metal wire grid in the lid is
a BAD idea. That shatters the lid from heat-cool cycles
(refractory and metal mesh expand at different rates!)
Instead, you pour a solid flat donut lid. Then, once dry,
simply add handles to the perimeter wrapped rim loop.
You drill blind holes in the lid refractory with a masonry bit to
allow it to be suspended via the handles' nuts protruding inward.
Ta Da... No more stress fractured lids!
A pretty cool event. After two one-day sessions, we all walked
out with working personal metal casting furnaces.
This was definitely the way to do this. It allowed for both bulk
purchasing of parts & cement, et al, and efficient building.
This way only required one setup and cleanup of the wet cement,
and we had lots of hands to come to our aid as needed.
Tools and crucibles were up to you (we WERE going to also
have a "tool making session", but it never happened... Darn...)
Rick's standard crucible is a slice of steel pipe & screw on cap
(welded solid), a couple of bolt heads on the top for tip pivots,
and a nut welded to the bottom edge-wise, to form a tip loop.
The tongs, scissor lift, and tilt bar were made out of rebar.
The tip scissors have keyhole cutout flat tab plates welded
to their ends to hook onto the tip pivot bolts, and another
rebar length with a J bend at the bottom hooks the crucible's nut "loop".
The "ingot form" for surplus aluminum melt was simply a slice
of steel L-channel, with plate ends welded to it (sloped out
slightly) to form a self-standing "V" trough. If you want even cheaper,
just use old recycle shop steel cupcake tins as "ingot biscuit" forms.
- Keith Mc.