Francis Trez Cole Posted December 31, 2012 Share Posted December 31, 2012 as far as the term case hardened or hardened, it is listed in some of the old pattern books. I will do some more research and let you know what I find. items like sugar cutters and food turners. They have an almost chrome look to them. I have seen dividers and tools with the same finish Quote Link to comment Share on other sites More sharing options...
Dave Budd Posted December 31, 2012 Share Posted December 31, 2012 The Holtsappfle book talks about using a burnisher to smooth the surface of wrought iron, and if you apply enough pressure (such as with a two handed and full bodyweight approach) you can get what looks like a hard chromed surface. Certainly the surface is much more uniform and shiny, presumably the iron is being smeared over the slag holes as it is polished. I've read somewhere recently (probably in one of the photos above) about burnishers being heavy weights suspended from the roof and the operator using his bodyweight to move them across the workpiece, suggesting that they are very heavy indeed. I had a flick through a couple of older reference books last night, but couldn't find much. Maybe they are worth a proper looking into by those interested ;) Namely the works of Diderot (http://quod.lib.umich.edu/d/did/) and De Re Metallica (http://ia600408.us.archive.org/13/items/deremetallica50agri/deremetallica50agri.pdf) I couldn't find anything in the Diderot catalogue, but I'm sure he wrote something on the subject of polishing iron (who wrote about everything else!). Agricola (De re Metallica) wrinting in the late 1500's, mentions the use of crushed emery for polishing. Quote Link to comment Share on other sites More sharing options...
GNJC Posted December 31, 2012 Author Share Posted December 31, 2012 Yes, thanks a lot Dave - all interesting reading. Good effort. Burnishing is something I have used for years (decades... ahg!) for silver and gold work. I've neglected it and now realise it is something to have a good go at. I have some old rail track that I can polish up, not yet able to go bigger. (I have vision of an old anvil being hung up...) Frosty, the rotten-stone on question used to be a common stone for sharpening stones over here (UK)before the decent oil-stones - mainly from the US - arrived. Quite fine grained and used for a final sharpening. Decomposed granite is often, but not always, kaolin (kaolinite) a.k.a. china clay. I've just done a web search and see it mentioned as weathered limestone mixed with silica, hmm... Not entirely sure about that; my first degree was in geology and I recall it as being a metamorphosed calcareous sedimentary rock. Metamorphosis generally involves movement down to a higher pressure-temperature regime than nearer the surface. Later tectonics or erosion then expose the rock we see today. The change in the rock's structure and its minerals and chemistry made it more friable and easily weathered, I guess it is this that lead it to be named 'rotten' stone. Quote Link to comment Share on other sites More sharing options...
Francis Trez Cole Posted January 3, 2013 Share Posted January 3, 2013 here is a link to case hard steel bookhttp://books.google.com/books?id=gPJZAAAAYAAJ&printsec=frontcover&dq=case+hardening&hl=en&sa=X&ei=VbXlUOyhPIa88wTs1ICoAg&ved=0CEEQ6AEwAg Quote Link to comment Share on other sites More sharing options...
GNJC Posted January 3, 2013 Author Share Posted January 3, 2013 Thanks, I'll have a look through that for case-hardened cooking utensils. In my own library I have found a reference to the historical use of case-hardening for kitchen knives, this is in the book 'Irons in the fire' by Rachel Feild. However, she has an odd understanding about a lot of metalwork and metalworking processes; so I take her writing on things other than historical fact with a pinch of salt. Quote Link to comment Share on other sites More sharing options...
WraithsNinja Posted January 3, 2013 Share Posted January 3, 2013 I once saw a video on youtube, can't find it anymore, of a man building a large copper cauldron. And at the end he was polishing it with what looked like a slurry of fine sand and water. I really wish I could find that video it was fantastic. Quote Link to comment Share on other sites More sharing options...
GNJC Posted January 5, 2013 Author Share Posted January 5, 2013 Thanks for that. Apart from commercial brands, here in the UK powdered brick dust was a common polishing medium used for domestic items such as pans. Cheap and plentiful, as were servants! Quote Link to comment Share on other sites More sharing options...
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