Sheboygan, Wis. (WHBL) -   A smoldering fire inside of a wall caused an estimated $4000 damage to a south side Sheboygan duplex Wednesday night.  The Sheboygan Fire Department received a 911 call about 5 o’clock from a the home at 1306 South 22nd Street reporting they smelled smoke.  Fire Commander Keith Risse said the family told firefighters that a plumber had soldered pipes around the bathtub earlier in the day.  Risse said firefighters were able to located the fire smoldering inside the wall and it was quickly extinguished.