Hi
I know that this can be an extremely fiery subject no pun intended so just to add another slant on the colour case hardening theme, it has been a sort of life long interest of mine to collect now no longer used Brit Engineering oddities.
I won’t bore you with the details how I came across this method of colour case hardening.
Here in Britland during and just after the end of WW2 all sorts of products where in extremely short supply or just not possible to get hold of included in this where engineering sundries of all kinds.
Now just to put things in order during and just after the war the Government encouraged us Brits to grow vegetables in our gardens, yes it is true we are a nation of garden lovers even today and I include my self. Well that being the case garden products where not hard to obtain at all in fact rather a lot of it about and one in particular was a fertilizer known as Blood Fish & Bone (That is exactly what it is). Which is still used here today in quite large quantities in what we call “organic gardening”, well an enterprising company used this product mixed with redundant Gas Mask charcoal to make their own colour case hardening product. I was assured it worked extreemly well and was shown a Micrometre trial piece that had been processed using this mixture and it had extremely passable case hardening colours. They do say “necessity is the mother of invention” at the same time our German cousins where using a standard Nitrate based fertilizer to Nitre Blue steel!!!!
