That is exactly what you do. Battery rebuilders do it all the time using a battery post mold.
A buddy of mine worked for a battery rebuilder and I watched him fix several battery posts using a mold and propane torch. I asked him if he was worried about the battery exploding. His answer was the out gassing is very low if the battery is not in use or charging and he had a fan blowing any gas that might be there away from the flame.
I wouldn't use the screw in repair posts because that could be the source of the next fire.
I find it very interesting that batteries can be repaired. The only time they release explosive fumes is when being discharged, or being recharged. I personally would not repair a battery terminal with a open flame due to the risks involved. If you chose to do so, please wear the appropriate PPE and do so in a well vented environment.
I got educated at a very young age of 10 about the power of batteries. Grew up from age 7 in my father's auto supply/repair shop seeing a lot of things. One day, a guy had his welding rig inside the shop and was using a grinder working on something on the back of the truck. My father had a battery charging within 10 feet of the welding truck. Sparks from the grinder found the battery, and it exploded. Sounded like a shotgun when it went. The battery was on fire, a small piece of the battery top was stuck in the ceiling and it caught fire. Acid was everywhere on the welding truck and it caught on fire. Fortunately dad had a couple of large fire extinguishers, and the drama was over in less than a minute. Scared the **** out of me.
Folks that didn't grow up around this stuff aren't aware of the dangers that come with owning these vehicles. They need to be made aware beforehand so no one gets injured.
I have seen a contractor take a welder and connect it to a large wheel loader battery set in the extreme cold in order to get it to start. Sure it started, but was it worth the overvolting the batteries and risking an explosion?
A few things that are mandatory when owning these vehicles:
1. Tighten and secure all battery connections. If the cable ends don't fit, throw them away and REPLACE THEM WITH NEW.
2. Bolt your batteries down and INSULATE the battery posts. And yes, they are in a steel enclosed box for a reason.
3. Invest in a set of slave cables. Do NOT open the battery compartment and use jumper cables. Using slave cables separates your eyeballs, face, and other tender goodies from the batteries when connecting/disconnecting.
4. Inspect your battery cables for frayed spots that will arc and cause mayhem. A0/A1 trucks are known to rub the positive battery cable just behind starter on the edge of the engine block. Double wrap with heater hose.
5. Install a up to date fire extinguisher and first aide kit in each of your vehicles, the extinguisher may save your ride, and the first aide kit will save someone's eyes. Trust me, when it happens you won't have time to get to a hospital.
Last of all, there are 2 common scenarios that cause batteries to fail/explode during normal use.
1. Vibration, age, and use cause tiny cracks in the plates of the battery internally. The battery will work fine, hold a charge, and seem to function 100%, until a major load is placed on it and then you get a spark/arc internally causing a kaboom. Usually they have a low acid level as well, allowing the cracked plate to become unsubmerged and thus the spark.
2. Loose cable terminals. Everything will work fine, alternator will charge and the vehicle won't exhibit any symptoms. Then a major current draw will occur, like starting in cold weather, you will get a spark at the loose terminal and a kaboom.
Hope this saves someone's truck and eyeballs.