Glenn

Hi Sabine, I don't think there is tutorial on painting a machine but if you look at the stickies you will see how to clean and repair the clear coat on the machine. You will be able to use this on the machine except for the bed. The painting requires a good sanding to a smooth and rust free surface. Prime with a good quality primer and then paint black. I use automotive primer and paint. Use a gloss jet black. After derusting and you have a good surface for repainting before painting wipe down with alcohol to remove and oil and dirt. You will need to apply three or four coats sanding lightly with fine wet or dry paper between coat with a block so sanding will remain flat with now ripples. No need to sand the final coat. You should now have a nice smooth surface to apply new decals. You can buy a spray can of clear shellac in Lowes or Home Depot to protect the new decals. Let the paint cure for a week before applying decals and shellac.
Other members have painted machines and I hope will come on board and provide more info. this will get you started cleaning the be anyway. Please read my tutorial first before cleaning the top of the machine. Make sure understand the process before starting on a machine.
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PS Most of that can be scraped off with puddy knife before sanding.