Woke up this morning to find the yeast (pitched 12 hours ago) crawling out of the top of the jerry-fermentor and making a mess of the fridge:
All it takes is the cap from cube or jerry, plus a 13mm barb to 15mm BSP poly elbow or director:
Drill a very-slightly too small hole in the middle of the cap, the 20mm hole saw is ideal, but a step-bit will work too.
Cut a thread with a 1/2 inch stainless nipple (or similar):
Screw in the elbow/barb:
Hole in the lid of the blow-off-vessel:
... and it's done:
It is in action less than 5 mins later:
It took longer to clean up the mess in the fridge than to make the blow-off-cap.