Full Chisel Blog

December 26, 2009

An altogether unusual abrasive

Filed under: Historical Material,Of Interest,Proper Tools,Techniques,Uncategorized — Stephen Shepherd @ 6:21 pm

I thought scouring rushes and shagreen were unusual abrasives, that is what I get for thinking.

I stumbled across this in some research I have been doing for an upcoming publication.  The nineteenth century publication on decorative painting mentioned that to smooth the cut edges of a pasteboard stencil one could use cuttle fish bone.  Those little white ovoid shaped pieces of chalky looking stuff hanging in birds cage, used for pecking, calcium and sharpening their beaks.  The cuttlefish is a relative of the squid and octopus and is considered a delicacy by certain people.

So not wanting to write about anything I have not personally experienced I gave this stuff a try.

The one on the upper right is one I tried some experiments with and the score marks are from cutting them from their packaging and the stuff in frangible, some powder is visible.  The one by the gnomon is a side view and all are the same shape, some are bigger and others are about this size.  At about a dollar apiece, not a bad price for a period abrasive.

I tried some on some hardwood, made it nice and smooth and it polishes soft metal and also works for its stated purpose of smoothing the cut edges of pasteboard for stencils.  I will have to do some more experimenting with its abrasive properties, I have also heard of its being used for a one off mold for casting pewter and other metals.

When I return home, I will continue to experiment with this abrasive but at first blush it looks promising.  Who knew?  This goes in the category of who was the first to figure this out?

3 Comments »

  1. Stephen, I always keep a bag of cuttlefish bones which are gathered on the shore following a storm, however, I don’t use them as an abrasive (apart from abrading each other), I use them for casting small runs of brassware such as missing handles and clock finials etc.

    Comment by Jack — December 26, 2009 @ 10:10 pm

  2. Jack,

    I have seen that casting process before, it was for one-offs. Are you able to cast more than one or does the bone deteriorate?

    Stephen

    Comment by Stephen Shepherd — December 27, 2009 @ 10:37 am

  3. Stephen, Depending on the condition of the bone and its size (larger bones withstand the intense heat better), it’s possible to pull two castings out of a pair of bones. I don’t count on it though and it’s simple to press another pair of bones if necessary.

    As you say though, the process is really more for those one-offs that aren’t in any hardware catalogues. If more than one copy is required, I normally go the lost wax route – that way I can also save an armature or mould for future use.

    Comment by Jack — December 28, 2009 @ 5:55 am

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