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