Originally Posted by TheSGC
I'd have to say rather insane. Battery repairing isn't for the untrained and I'll never do it. Things could go horribly wrong later on. Or immediately. You should really get it replaced, unless someone else has another idea.
What planet are you from? Your statement is well, foolish. What could go horribly wrong? Might he spill acid again, might he put a hole in his new suit or have a short? Oh no that happens anyway at some point! This repair is no more dangerous than putting acid in a new battery.
If you can deal with sulphuric acid you can repair a battery case.
Get appropriate old clothing you care nothing about and a safe non-paved location, baking soda and some warm water and an acid proof funnel and container. Also a pair of safety glasses and some "acid refill" from a local store
Dump out all of the acid into said container
Clean the broken area then dry with paper towelling or low lint junk rags (obviously if it is REALLY smooshed you may have impacted the plate and broken it, otherwise continue)
Liberally Apply your favorite patch or putty over the entire area. Do as you would to seal a radiator or any other liquid leak. YOU DO NOT NEED TO WELD PLASTIC to seal it. See the videos at the bottom of the page.
I especially like the video showing you how to clear a battery short with a coat hanger.
Also something of interest to the more hardcore
Contrary to what many believe a battery is LESS dangerous than soldering with leaded solder, the acid is biodegradable and normally newer lead acid batteries have minimal amounts of actual physical lead in the acid. Also you are not dealing with lead powder or smoke which is the most dangerous type of exposure.
I have had very strong acid on my hands many times in chem lab and needless to say nothing happened, you just calmly wash them and apply baking soda, if you leave acid on your skin long enough it starts to tingle and burn but it takes much longer than you may think. And obviously don't splash the acid up into your eyes, always wear safety goggles. And obviously don't wipe your eyes with your hands after handling acid and eat/drink during the event, duh!
The main issue with sulphuric acid is its effects on concrete and clothing aka it destroys them, which is why I keep a junky pair of clothing for just such an occasion.