Cooling coil material for HF acid etch bath?

We are anodising aluminium sheet parts since a long time, but recently have to anodise Silicon- bearing cast parts. These are first etched by us in dil 5% HF bath in plastic (PP) tank at room temp (about 30C),then swilled in dil nitric acid bath before anodising. The results are acceptable to the buyer. However, we face the problem of HF bath heating up incresingly as subsequent batches are treated in it.Could anyone suggest the cooling coil material to be used in this HF bath. Any help would be highly appreciated.

PTFE(polytetraflurethylene) also known by the tradename TEFLON

Hi Malvinder

What Gene says makes sense but also investigate a material called PVDF .... should cost far less... available,I believe, from G.F.Fisher

Freeman Newton - White Rock, British Columbia, Canada

Ed. note: Please keep Freeman in your thoughts & prayers. Message from Freeman, Dec. 2010