I use propane also.My first strip went fine. Emptied her out and loaded up for round two. This is where it got exciting in my garage. Took off some fores and they were pretty hot so obviously the water in my barrel was to warm from the last run. No biggie, I have the hose right here so I just add more water and let the hot go out the over flow. I do this, sit back down (stripping run, collect in gallon jugs since there are no cuts) about a quart into it, THUMP! The head pops off my boiler and there is a FIREBALL in my garage.
Fortunately, I am sitting by the worm with a hose and spray nozzle. The wife/still hand pops right to the workbench where my two fire extinguishers are (thank god those messy things weren't needed). We reacted smooth 
. I spayed the fire out in seconds with the hose then she set down the extinguisher and got the tank shut down (propane tank is a large one I keep outside the garage).What happened? A couple of things. One, I did not tap the head into the ring very well. I usually lightly tap it with a dead blow mallet to get a good fit, not driving it in, just tapping it. This time I just hit it with the heel if my hand a couple times and wrapped it with flour.
I think my biggest mistake could have involved shock cooling though. My worm is 5/8" OD coil, 50', I have it wound and braced very well so it is even with no low spots but the slope is very gradual. I have always noticed that if I just add water to the top it interrupts the output flow by messing up the gradient. When stilling I always insert a pipe to the bottom of the barrel and add the water to maintain the gradient. This time I figured it did not matter since it was just a stripping run, who cares about smearing and such.
Well thinking about it, if you have a heavy stream coming out and it stops when you add fresh water, where did it go? It built up higher in the coils.
This probably dammed the coil up with distillate causing some back pressure. The head not being very secure just either popped or sprung a leak that ignited and blew. Either way, I was being sloppy and that was dangerous 
.I have often thought too that bigger is better for anything cooling wise. I guess there is a limit to this. While the larger worm does cool well, that is a long way for a large volume to travel when striping. I can foresee a condenser build coming up this winter for stripping runs. Right now I guess, I will just throttle it back a bit.
And yes I know..... This is one more example of why an electric still is safer than using propane.....
Maybe one day.Good thing is nothing burned but the concrete floor and my copper boiler. The bikes are safe. Water puts out alcohol just fine.
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Like you are expected to do . No panic ; just 'Houston , We have a problem', and then you took care of it and reported 'all secure'. Minimal damage 'learning experience'.
