DanM

A regular hacksaw to rough cut and files to shape.a number 6 will work ,but the number of broken blades and time involved is not worth it. Recommended blade size link https://www.firemountaingems.com/resources/encyclobeadia/charts/771x

There has been an impact engraver which uses a flex shaft for power since 1979 http://www.ngraver.com/

Push engravers and hammer and chisel for under $200 to start with and see if you like the technique.No point in spending 2 thousand for something you might not enjoy.

Have you checked http://www.engraverscafe.com/forumdisplay.php?1-Hand-Engraving-Forum Like Lindsey's forum it is full of info and advice and the members use all types that are good.

what type of stone?

Did you check the ingredients of the "white out" ? A number of brands do not contain the titanium dioxide for it to be a release agent.

Try this ............ http://powning.com/jake/tutorial/carving-tutorial/

They will turn the copper black at the same time.

Someplace on you tube there are videos of making thin round wire for silver filigree mostly in the Mediterranean area. The annealed wire can be reduced in thickness by rolling between 2 flat stones/metal plates. History of draw plates... https://link.springer.com/content/pdf/10.1007/BF03215438.pdf

Polishing is the worse thing you can do to mokume, a satin finish is much better to see the contrast of materials ..... https://contenti.com/polishing-n-finishing/buffing-wheels/satin-finish-wheels/2-3-ply-satin-finish-wheels There is nothing I know to "seal" it,maybe a little olive oil after washing.

A photo might help,but your metal combination should have been thought out first.

Not the thread you are looking for but ... http://www.williamhenry.com/materials/view/material/id/2/ maybe this one

The blade can be coated with finger nail polish,it depends on what acid you will use. What is the handle material?

What material are you using?