This is a bit wordy but bear with me.:76:
The stud will heat much faster due to the insulating properties of the corosion.When the stud expands it in essense compresses the corosion. Then when the stud cools
and shrinks much like in flame straighting. it
can help to release the grip on the threads You can help it to cool with a gental squirt of water to help "shock" it.
From my years doing field service of heavy equipment I learned a great trick a removing bigger studs.They can be broke off rather deep in the hole, even on aluminum castings. This method works well if you have the nerve to try it.
Step 1. Get a stick welder.A rod like 7018, not a 6010 like rod is best.
This can also be done with duel shield if your good. The big trick to this is the flux will fill in and protect the threads while you build a nice new stud on it to weld to the nut as mentioned earlier.
Step 2. When using the stick, you disconect the ground, insert the rod down in the bore centered on the stud.
Step 3. Very carefully hook up the ground to start the arc. This is best done by a helper so you can keep the rod centered.(You at ALL COSTS do not want to strike an arc on the threads!!)
:looser
o this and its time to head to the drill press and good luck drilling through what you just did.:fawkdancesmiley: and feed the rod
STRAIGHT
down on the broken stud.let the flux flow out into the threads .I will build weld up on the stud and the flux will flow in to the threads to protect them for the stud to screw out on.:cheer: This like all welding takes some practice.
best of luck I hope this passes on something usefull.:nana1: