Not all soldering irons are created equal, nor should they be confused with soldering guns. My Hakko soldering station has the ability to set the desired temp and has interchangeable tips. So comparing it to a $10 Harbor Freight iron is like comparing their screwdrivers to Brownell's gunsmith bits.
The soldering iron works very well to provide steady controllable localized heat. You aren't trying to cremate the Loctite, just soften it to be able to break it's bond, which should happen at around 400 degrees. Here are some things to remember about Red Loctite: It's binding capabilities are dependent on several factors including how well the surfaces were cleaned as well as the amount applied. Like Brylcreem, a little dab will do you and make disassembly much less painful. Red Loctite applied to larger bolts that can be securely gripped with properly fitting six point sockets can usually be dsassembled cold, but on small gun part screws, such mechanical purchase and the ability to add mechanical leverage either isn't available or is ill advised due the slip and breakage factor possibility. Heat transfer rates also vary greatly depending on material. Generally speaking, 400 degrees isn't going to damage anything unless you have surrounding wood, or possibly some anodized finishes. Again, remember the goal here isn't to turn the screw head red, it's merely to apply enough heat to soften the Loctite bond. Apply heat for a ten second interval, then try a properly fitting wrench. Without applying too much force, if it doesn't break free, apply more heat and try again. As stated, the amount of heat needed depends on the amount of Loctite applied, as well as the surface area and prep of that fastener. After breaking the bond free, you need to spend time cleaning out the remaining loctite from the thread surfaces with a small wire brush for the screw and the proper sized tap for the hole.
And in the future, put the red Loctite away for use in your hot rod engines.
