On Tue, 4 Nov 2008 01:21:07 -0800 (PST), wrote:

I bought a toaster oven from Goodwill for $10 and removed all four 12
inch long Calrod heating elements. I say Calrod, which is a brand
name, and mean the type of element in a metal tube with MgO
insulation, not the wire coil in a quartz tube. They were wired 2/2
series/parallel in the toaster oven and each rate 575 watts.

I chucked one in the lathe drill chuck and placed the wire end loosely
in a tailstock drill chuck, then applied abrasive paper. I noticed the
outermost ends could be sandpapered to a bare steel finish, while most
of the length would not give up its grey oxide finish, most likely
from use in the oven.

I strapped one onto the inner surface of a bend I'd made before in 1/4
inch acrylic, connected it to a 300 watt lamp dimmer, ran the power up
slowly until the dimmer made the noise characteristic of passing and
clipping AC power, and ran the power all the way down, to find that at
this setting, the element would not even boil water. I ran it up very
slowly, and eventually got a pretty clean re-bend in the acrylic. A
half-wave rectifier would have doubled the control range. Full power
to one element would fry the cheap $5 dimmer. Four elements in series
definitely would not.

I'll clean the stuck plastic off the element with lathe sanding as
before. Maybe I'll wrap it with Tefflon tape next time. There was only
a little sticking.

I used the heating element from a dead (Maytag) dishwasher. Original
shape is most of a circle with the ends turned down through the bottom
of the tub, I straightened this circle out to give a 44" long rod with
ends turned down. I mounted this in the 2" deep x 2 1/2" wide sheet
metal channel from a 48" single tube fluorescent fixture. The ends go
through the channel into attached 4" octagon boxes to enclose the
exposed electrical connections. At first, the element bowed up when
heated, so I cut a slot and provided a sliding mount about a half inch
long. The element is designed to operate on 120 volts.

I have the $40 metal bending brake from Harbor Frieght and hope to
integrate one element into the brake to heat plastics at or near the
bend point so they can be accurately bent. I'll need a bend clamp or
stop while the whole setup cools. I overloaded my bender and the steel
pivot body cracked. Cheap Chinese **** and one year warranty expired.
I'll have to duplicate the bending bar clamp holes and the mating
threaded holes in the back half of the new bender. The pivot body, of
course, was made of compressed Diet Tab bottle caps.

I'm just reporting on some of the fun I've been having here at
Replikon Research, working mostly on the MOEPED for my one-credit
Seminar and Project at NVCC, PHY 298, and developing a fully expanded
specification for a self-reproducing universal machine tool. And it is
fun.

A fully expanded universal machine tool could make it's own
transparent plastic machine guards, could mill flutes in a drill, mill
or reamer bit, grind or regrind bits, etc. There are lots of loose
ends to finish off.

Doug Goncz
Replikon Research
Seven Corners, VA 22044-0394
(Why not send me a QSL? That's a valid, complete postal address, at
least the clerk said it is.)
Gerry :-)}
London, Canada