Cool Beenz... Make Damned Certain to
AVOID ALLOWING THE OXYGEN LEVEL IN THE FLAME TO GET TOO HIGH.... Or it will start to Cut Through the Adjacent Cast Iron...
LIKE BUTTER. Temper your approach by
Constantly Moving the Tiny Brass Torch Nozzle around the Threaded Hole Perimeter
(NOT Directly onto the BOLT). This action will bring those areas surrounding the Broken Bolt up to an
Incandescent Glow in order to allow the Cast Iron to expand away from the Bolt.
BUT... IF YOU BEGIN TO SEE 'BRIGHT WHITE SPARKLERS' COMING OFF THE WORK PIECE... IMMEDIATELY BACK THE FLAME AWAY AND LOWER THE OXYGEN LEVEL. You WILL require
Welder's Glasses even for Non-Electric Welding as in this case because the Torch Brightness will still be
come Blinding to you while you're concentrating your Vision over the
Flame Spot on the work piece.
DO NOT SKIP THIS STEP!
NEVER, EVER SPRAY BRAKE-KLEEN OR ANY SOLVENT CONTAINING POLY-TETRA-FLUORINE-ETHYLENE (TEFLON) ON ANYTHING BEING HEATED WITH A TORCH AS THESE SUBSTANCES WILL COMBUST AND CONVERT INTO PHOSGENE GAS AT AROUND 900 DEGREES FAHRENHEIT. ONE WHIFF OF THIS STUFF CAN KILL YOU!
Please know that the
O2 will run out fairly quickly
...the MAPP Gas? Not So Much... whenever using those
Small Red OXYGEN Bottles, so prepare your Work Area, solidly secure the Work Piece and have your Tools arranged in such a way that you won't need to keep the Torch Turned ON for an unnecessary time frame while trying to find & figure things. And
as suggested by @JayArr... Use a Fat, 'Hurricane Candle' to touch in and around the Broken Bolt Piece, as it will work its way into and around the Rust Frozen Threads.
When you are done, TURN OFF THE OXYGEN Adjuster Knob FIRST ...then do the MAPP Gas. DO NOT LEAVE THE TORCH-HOSES-FITTINGS ATTACHED TO GAS CYLINDERS. Snug up the Adjuster Knobs (Don't Over-Tighten them) and unthread the O2 Bottle FIRST and then use some Spit on your finger to glob over the Schrader Fitting on the Top of the Bottle to ensure that it is NOT Leaking. Do likewise with the MAPP Gas Brass Fitting-Hose and Store these two bottles on different shelves if you do not have a Bottle Caddy. Coil and secure the Torch and Hose Combo inside of a 2 Gallon Zip-Lok Baggie to prevent the Brass Fittings Cork Seals from getting damaged and having any dirt contamination getting all over the Kit.
Optimally... (Courtesy Duane and Company from "RealFixesRealFast"... THIS is how this work should proceed:
Don't forget to Wear Heavy Leather Work Gloves when working on removing the Bolt to avoid getting stabbed in the fingers or burned should your Grip on the Pliers-Channel Locks slip and you accidentally make contact with that 'Bag of Snakes' of Broken Flex Wires on that Work Piece.
