Metal blackening is a subject I've seen raised a few times here, I bought a kit recently and was quite pleased with the results, so thought I'd give others a heads up.
I bought a 4 part 1L kit from a company called 'gateros' for £37.50, this includes a degreaser , acidic etch, the black itself, and a sealer, some kits seem to be 3 parts, minus the acid etch I think, and costing more too.
Restoring this old Jones and Shipman press I thought it's quite a nice tool, might as well do it properly and buy a blackening kit, came out pretty well and used virtually nothing, 1L of the blackener should last years for the odd nuts and bolts etc

