[QUOTE=roverhi;1768504]You might try the jumper cable trick. Hook the jumper cables
up to a battery in the normal way. On the other end, put a bolt in the postive lead clamp. Clamp the negative (black) as close to the offending bolt as possible. Touch the bolt in the positive lead to the head of the fastener. You are essentially setting up an arc
welder. It will heat the fastener to a cherry red if left in contact long enough. It works really well as you are heating just the area of the fastener and not burning up the surrounding area plus getting the fastener way hotter than you can with a MAPP torch. Used it to remove all the fasteners that wouldn't come out with the battery powered impact tool on my 40 year old mast
. Worked a charm and also used used it to get corrosion
welded bolt out that passed through substantial aluminum castings on the self steering
Having said the above, the hardest fastener to remove is not one that is threaded into aluminum but one simply passes through an aluminum casting like cleats, etc. Getting the bolts out of the self steering
casting took something north of 25 iterations heating with the jumper cable and quenching with penetrating oil over many days. Have a couple of bolts in aluminum cleats that I've been trying to remove for a couple of years without success. The cleats were through bolted so I got them off the boat by removing the nuts but can't get the bolts out of the cleats.
Sounds like a handy trick, albeit one I'd be cautious in using until I had a good feel for using it. Though the same idea works well to help to extract stuck wires used in stitch & glue construction.
Not that the cleats or bolts are worth much by now, or removing at this point, but you might try the Coca-Cola or Vinegar trick. Meaning, use a mild strength, semi-wicking, acid, to penetrate the area(s) built up by salts, & corrosion (oxides & mineral deposits).
It works with varying degrees of success to clean up the corrosion on & in battery cables, still hooked onto the terminals. Or at least once or twice, anyway. As much past that, I'm not sure how much of your battery cables you'd be dissolving.
And no, I'm not brave nor foolish enough to try & flush out such a brew with fresh water
. I don't care to be a human ground wire. If we unhook the terminals, then that's another story.
But Vinegar might be a good bet on the cleats, were it not for aluminums abysmal location on the galvanic scale, & thus as an educated guess, it's less than stellar resistance to being gobbled up by the vinegar (Acetic Acid).
Still, given that you could throw the whole mess into a clear jar or bowl & thus observe the proceedings, with frequent hands on checks for progress, it'd be an interesting experiment
And if someone wants to do a test run of vinegar vs. aluminum, it might help the OP figure out if such might be a viable tool to use in the fasteners conundrum.