Get a regular non alkaline D cell flashlight battery.Remove the top and gently pry out the carbon rod.Read gently.Now you need a hot 12volt battery.Put the carbon rod into the red clamp like a welding rod in a stinger and hook to hot on the batt.connect the ground to the batt and the other end to the vehicle.Using the little carbon rod touch this to the area needing heat,maybe 2-3 seconds only.Touch and pull away as you would strike an arc in welding.Rod gets red hot so this is where good clamps are needed.The heat is concentrated to a specific area, bolt head,nut,etc.I removed the threads from spark plugs(all that was left in the heads)with a small easyout and a 4" crescent wrench.The plugs had been installed with an impact!!Also removed the vent screw on an alum boat motor with this method.I know this can be dangerous to do yet if used in a safe manner it works.I recommend trying this on a work table to understand how this works as opposed to on or in a vehicle.There is no spatter like welding or torching,just concentrated heat.The carbon rod can break if dropped or used aggressively.Get another one.
Muley

How about using a carbon arc torch rod?

How about using a carbon arc torch rod?

Far out. Never heard that one. Candle wax yes, carbon rod, no.

This idea was given to me and a friend by his sons gfs dad.HE got it from.....McGuyver,yes McGuyver.As to the carbon arc rod,that may work instead of the battery rod.I personally havent tried the CAR,Sounds interesting,tho.

Here is a similar site that uses this for melting. Some safety caveats as well.

http://arcmelt.velp.info/

Interesting technique!