Topfmine,

I don't use any pre dip, but the item will need to be cleaned to a high standard and after this I bead/sand blast it, for the dark Manganese finish I use fine wire wool as BR mentions, don't waste your money on solutions etc, two main ingredients can be bought on ebay, as for water I now collect the water from the drain on my condensing boiler.

The link below is when I first started to experiment, there is a formula near the end which I now use but still add the wire wool.

I did a few bits for a forum member some time back and one part I couldn't get a nice finish on, could not work out what was wrong until I was finishing another part, it turned out the part was resting on the bottom of the tank so was taking more heat than normal.... lots of head scratching but eventually got to the bottom of it.

Home DIY phosphate/ parkerizing process