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I Forge Iron

Steel shot blasting

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I just finished prepping a load of forged railing with Black Beauty "medium grade" with very fast results. The mill profile is a bit rough, though. Perhaps in the 3 - 4 mill range. This requires a lot of primer and top coating to smooth out, masking my hard-earned hammer marks more than I'd like. What size/grade/type of steel shot would efficiently remove forge scale but give a smoother surface, say closer to 2 mill? My local blast media supplier has steel shot but wants to know what grade/size I want.
I've no idea!!!
Any advice would be most appreciated.

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Regarding blast media there was a discussion on here a few months back that I was involved in:-




and there are probably others...


I would also ask your suppliers' technical department what they recommend for your application...they should either know themselves or be able to ask their suppliers'.


The loss of hammer marks is always a probability if you use an eggshell or gloss finish. The best way to restore the detail and bring out the forged texture is with a burnished graphite top layer. It has likely been discussed on here before I think. 


Flake graphite, mixed in with eggshell paint, sprayed on, and just as it is going off, rub the surface to burnish the graphite. My favourite is with Levi denim. It highlights the ridges and remains black in the pits which makes it look very "irony". If you use a shoe brush it burnishes in the pits and you do not get the dramatic contrast. 


You can even make a piece of wood or concrete look like iron with this system. It will even bring back the forged surface which is obscured by the homogenising/flattening effect of zinc spray or galvanising.


You can use it with any colour, black is normal, but red makes the piece look like it is still hot and blue looks very classy but the blue tends to fade in sunlight.


I always specify a wash etch primer rather than a high-build which keeps the paint layer as thin as possible commensurate with effectiveness. When used on top of a zinc finish as far as corrosion protection goes the paint is purely cosmetic anyway. 


Like any graphite finish it is not the best for handrails or door furniture!



Edited by Alan Evans
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