Know How On How To Get Depositon Of Carbide Tip

As you claim, the bridge rectifier doesn't like your setup.

Try it with a heavy battery in parallel as smooth storage device.

Or make the load lighter - sometimes some voltage drop over a longer (or thinner) wire may do it.

If however, the capacity is reached (supply/demand) you should also consider a more heavy bridge

and even a more heavy transformer or

a second power supply.

try this. http://www.youtube.com/watch?v=EoWMF3VkI6U

While at Natal University i did a detailed study of the cause of micro cracks in sintered carbides (like in tool tips) during the spark erosion machining process.

Investigating various tool tip materials and the effect of the sparks on the target material. The object being to determine the best way to re-furbish worn /broken tool tips using wire or electrode spark machining.

In all cases using a scanning electron microscope we found that micro cracks had occured around the periphery of the crater and through the floor of the crater. No matter how big or small the spark and the size of the crater the results were the same, the same tell tale cracks rendering the process unsuitable.

Maybe elevating the temperature of the tool tip to a high level during the spark erosion process might be the solution???? Cost then becomes a factor.