Wednesday, May 30, 2012

Engraving mild steel

I bought some new mild steel sheet yesterday. It was 1.5mm thick. It was much newer than the other steel I got. It sanded clean very easily and was not pitted with rust. I engraved this with a 3mm slot drill, a 1mm slot drill and my engraving tool; nominally 27.5 degrees half angle, 0.1mm cutting diameter at the tip.

I was pleased with the result, although I had to tidy it up with my pen-knife and sand and polish it to get shiny ridge tops. Also, the fine detail pass at 0.05mm depth left a step on the ridges.


Having had trouble with engraving steel; it was probably hardened steel though, me and my assistant went to see a chemical etching expert on the Welsh border, last Monday. After getting some advice, we bought some supplies from Maplin in Hereford. We tried cleaning up our steel sample pieces, applying the Press N Peel transfers and putting them in the Ferric Chloride solution at about 30 degrees C. It only removed about 0.01mm of the steel in an hour. We left it over night, but it had only taken off about 0.05mm.
In the picture, we were trying electro etching using salt solution; John's idea. It took off enough material, but was not a good surface finish.

We need to try it while agitating the liquid, because some of the areas between the lines were not etched at all. We had to remove a layer of crust from the metal. So, we've bought a pump.