As part of my new fishing/boating hobby I find myself working on outboard motors. One thing I have discovered is that when dismantling an old outboard you can guarantee that no matter how careful you are a number of bolts are going to be seized and will shear off. So far I've been lucky enough to be able to drill them out, but at some point there will be one I can't do that with. Does anyone have plans, or links to plans, for a very basic spark eroder that would remove the snapped bolts? I'm sure I have seen small, basic, spark eroders for just this purpose.
On a related note, any tips for removing seized bolts would be helpful in case there are any I haven't tried yet. Mostly steel or stainless steel bolts in aluminium, and the corrosion is obviously due to years of being in salt water.