Wednesday, June 11, 2014

Porcelain Table Lamp with Broken Metal Base

A customer brought this patient in and admitted trying to fix it himself. He was trying to use common parts from a hardware store and not lamp parts. To fix this lamp properly we'll need to use the right parts and the right techniques. Some parts for this repair include: solid brass lamp base, seating ring with recessed center and rolled edge, rubber washer, 2 - 1 inch brass seating rings, and a steel nut. Of course we will reuse any part from the lamp like the lamp cord, lamp socket, harp base, and lamp harp.
broken base on a ceramic table lamp
First thing we need to do is take the lamp cord off the lamp and unscrew it from the socket. Repairing the base or tightening the threaded rod holding any lamp together almost always requires removing the cord to get the wrenches in place. After removing the socket shell from the socket cap, you can see there is no UL knot. (Someone wasn't reading this blog and didn't pick up on the importance of the UL knot).
I unscrew the lamp cord from the lamp socket interior and pull the cord out from the bottom. After inspecting the cord, I determine it is in good shape (polarized, no pinches, no pulls, no scrapes or thin areas) We will reuse this cord on the lamp. Now I can take the old busted base off and have a good look at it. The old base is made from white pot metal and is very brittle. Looking around the spare parts room we found a solid brass base that is turned in color and will look really good on this lamp. Solid brass is a better material since it is malleable and will not deteriorate with time or pressure.
pot metal lamp base and solid brass lamp base
Next I remove the threaded pipe from the lamp body and place a rubber washer on the seating ring. This rubber washer will help absorb some of the engergy and pressure from tightening the threaded rod. Anytime you are working with brittle materials like ceramic or glass you should consider using rubber washers, felt, or cork to help absorb the pressure and hold everything together.
Next I will add some felt to the seating ring with rolled edges. Just like the rubber washer, these felt circles will help hold things in place when we tighten the nuts on the threaded rod.
We start putting the lamp back together and place the ceramic lamp body back on the threaded rod and the new seating ring on the base of the ceramic body.
I place a nut on the threaded rod and tighten the lamp. I want to make sure my harp base is pointing in the right direction (pointing out the width of the lamp base). Having the nut at the base of the seating ring will allow me to get the right tension on the threaded rod holding the ceramic body in position. When we add the base, we are only tightening it to the seating ring and not the ceramic body. Now we can add the new old base to the lamp followed by a seating ring and a steel nut.
We push the cord back through the threaded rod and tie a UL knot.
The socket interior is placed back on the cord. To be polarized, the ribbed wire goes to the nickel screw and the smooth wire goes to the brass screw. I pull the slack of the cord back through the base, line up the turn knob on the socket and lock the socket shell into the socket cap.
The harp is placed back on the harp base, screw in a bulb, plug in the cord, and make sure everything works as expected. The customer was very happy with the results and the new base looks really good. Total cost: < $50.00 (including $40 for a new base) Total time: < 30 minutes