B.B. wrote:

In article ,
Grant Erwin wrote:


I'm making up some welding positioner clamping screws, and I'm gluing on
copper
tubing to the exposed shanks so spatter won't stick to them. I'm finding that
the bond to the inside of the copper isn't very strong, probably because the
surface is so smooth. Anyone have a slick way to easily rough up the inside of
copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do
they
make those?

GWE


Get a chunk of all-thread just slender enough to fit inside the
copper tube, but way too long. Chuck it in a fast drill, slip it into
the tube, and let 'er rip! The all thread will start to wobble around,
and do all kinds of terrible things to the inside surface. Kind of like
what a socket does to a stud when you take off a nut too quickly with an
overpowered impact, but backwards.
You could probably enhance it a bit by beating the **** out of the
all-thread before starting.
Wear gloves and glasses. A flak jacket can't hurt either. (:

You forgot to tell him to stick the whole works
in a bucket of sand before you start the drill....