For a long time, snapping the arm of your Anglepoise lamp meant its doom or at least an ugly Heath Robinson repair. Now with the development of super low temperature aluminium welding (or Brazing), a once expensive specialised technique has moved out of the workshop and in to your shed or kitchen.
In our current restoration series Ron in the workshop had to deal with a 70’s Herbert Terry lamp with a broken lower arm. To make matters worse the damage was across the main pivot point making a difficult repair more complex. So if you’re faced with the same problem as our lamp we hope this article and Ron’s video is of help.
One thing to point out, this technique works very well on either one of the lower side arms. However as we are inserting a rod into the arm and effectively blocking it, then there is no room for an electrical cable to run inside of the repaired arm after it is repaired.
If you’re damaged, bent or broken arm needs to remain hollow in order to allow a cable flex to run through it, the use of a hollow square section or round tube and NOT a solid rod as show in the demonstration is recommended. The principle is however the same as shown by Ron as he repairs this Anglepoise Herbert Terry 1227 lamp in the workshop.
Here is the video.
A few extra points to note.
The brazing rods used in the demonstration ( here ) are the lowest melting point blend we could find on the current market by far. They still do require a temperature of 300 degrees C in order to melt the brazing rods. We achieved this using a plumbers blow torch, other alternative methods you could use if a blow torch not available are:- Disposable BBQ tray, gas hob in your kitchen or gas BBQ.
A note of caution obviously when dealing with 300 degree hot bits of aluminium and noxious gasses, take the appropriate safety precautions, ventilation, gloves , eye protection and if the moulting hot brazing splashes fall on the kitchen carpet burning a hole through it…. wife wrath protection may also be required.
As stated in the guide, it’s the heat in the arm and not the heat from the flames that melt the brazing rod. Clean the aluminium to a bright finish just before you braze as it rust in a very short time, reducing the strength of the weld as the rust or oxidization prevent a secure bond.
Remember it’s a one shot deal with this brazing technique, re-heating the work piece to do additional brazing will melt the other welds when they’re allowed to also reach 300 degrees. On a terminology note this technique is strictly speaking not welding as the original broken pieces are themselves not melted together, it is the filler metal that bonds the two parts together in a term called brazing. When we refer to aluminium welding in the video and article it is for ease of understanding and visualisation.
As ever please feel free to post comments and questions below or on the YouTube channel. We hope the guide was of help and stay tuned for the next episode where we actually start putting our lamp back together. Thanks for watching.