Black scale and green soft soap

Michael Gilligan:

Thanks for the link to the fascinating Wiki. I am confident that "ingredients creep" applies to a great many products and that this normally only comes to light if the PR department decides it's "new and improved".

I shall make a point of not trying to teach my grandmother to weld soap!

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MichaelG.

I had a bit of a discussion with a clock restorer on this subject. He reckoned any sort of soap should be fine. I've tried it a couple of times without any real luck. One point he also made is that what is left of the soap should come off when the item is plunged into water. That leaves me wondering if it needs to be a thick coat.

What I found is that if the part is heated to quickly the soap just burns off leaving nothing and if I treat it in the same way as using soap as a temperature indicator to anneal aluminium it doesn't come off when quenched.

This leaves me wondering if clock people get away with it because the parts are generally small and quench rapidly.

John

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For small items like clock pinions it's usual to bind them with soft iron wire and coat the whole thing in soft soap. I make it by grating a bit off a bar of household soap into a small amount of water and leaving it overnight to become a paste. As noted above, don't use liquid hand "soap". It is not soap but a detergent/glycerine mix.

Russell.