Ceilidh ... Re^5: 3" Deep Draw Tip

Hydraulic Die Forming Discussion Group

Re^5: 3" Deep Draw Tip

On Tue Nov 5, Darren de Lacy wrote
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Hello. I am not doing deep draw work, nor doing much with silver. I have done some reading which suggests that orange peel is most directly caused by the time at annealing temperature.

My own work with copper supports this. I get better annealing, and zero orange peel, when I use my test kiln instead of a torch. Most common fault with a torch: working in too bright a back ground light. You cannot see the colour change when it first happens, so you keep heating until the piece glows relative to the bright ambient light: too hot.

According to the Olin manual on copper and brass, orange peel is a regrowth of large crystals which starts to happen at the anneal temperature. The longer you hold it, the bigger they get. The stretching or breakage occurs at the boundary edges of the crystals. Small crystals (ie fully annealed) yields invisible stretch marks.

I hope this is of some help.
Brian Ross

Wed Nov 6