Greetings.

I am making a lamp for my living room. I will use a 45 pound plate for the
base and some 1/2" rebar for the lamp itself. Base will be on one wall and
light bulb will be about 7' away. I need to bend an 11' piece of rebar
into a perfect arc. It would be 180 degrees of a circle. I am thinking to
make a fixture out of plywood. Fixture would be similar to what an
electrician would use to bend conduit. I don't intend on heating rebar.
Just bend on fixture. Other way would be to create a fixture using a
complete sheet of plywood. I think that is overkill.

Any thoughts?

thanks
Bob

Decades ago as a teen I helped my Dad build a greenhouse from 20 foot 1/2"
rebar bent into similar shapes. We had a straight section, then 180 deg
bend with 4 foot radius, then final straight section. Stood 5 of them up in
an 8x12 foot concrete slab and welded up a rebar center main beam and
stringers to brace it up. Dad did the layout and fine bending, I did the
welding with an old stick machine. Cranky neighbor came over and said that
the first wind would blow it down so I jumped off the ladder and did a
couple of chin-ups for him and he went away looking even more sour (Dad hid
his grin but I saw it :-)). It's survived about 6 or 7 hurricanes so far
including Frederic and Katrina and the edge of Maria :-). Anyway, we drew
the shape with chalk on the concrete patio using a string as a compass to
draw the semicircle, and did the bending over the 2 or 3 foot diameter
center section of a large cable spool we used as a patio table. Use a piece
of rebar a few feet longer than you want so you can cut off the ends where
the curve won't be perfect. Bend a bit, check against the chalk template,
rinse and repeat. Bend in small well separated steps, make sure you don't
get any twisting, and you should be fine.

--
Regards,
Carl Ijames