My sister bought me a Radio Shack Dual Heat soldering gun (150W/230W). This
was to supplement
my 120 watt 45 year old Weller. This after my WW II vintage 120 iron died
on me.

My main use was to solder coax connectors. The Gun seems to work Ok on
soldering joints in say a SB220 amplifier. But the first thing I noticed is
that the tip is much to large to fit into the area where the PL-259 outside
allows you to solder that to the shield thru the wholes in the 259. No
problem but if you leave the gun on too long the area of the tip gets red
hot about 1/2" back from the actual tip.

My old Weller does a better but inadequate job of soldering the 259 shield.

Why does the gun allow the tip to get red hot away from the actual tip. The
tip is almost new. I notice its made from a silver metal not copper as with
most Weller tips. Radio Shack tells me its made by Weller
and they are not aware of the problem.

bad tip or maybe a bad winding in the gun? any ideas?

Dave K4JRB