Unfortunately this doesn't work 
I tried this with 2 lights recently, one cheap plastic shallow dive light and one cheap 1600lm non-diving zoomable torch from ebay.
Both went down to 30m and worked fine when down there but the beam is affected by the oil to the point where they barely shed any useable light. They were easy to fill and the shallow light held the oil well. The non-diving torch needed some inner tube, but was tight after that.
It's a shame that the beam is so badly affected, one £8 and one £13 bright diving torches would have been great.
If anyone needs about 3l of baby oil let me know
I tried this with 2 lights recently, one cheap plastic shallow dive light and one cheap 1600lm non-diving zoomable torch from ebay.
Both went down to 30m and worked fine when down there but the beam is affected by the oil to the point where they barely shed any useable light. They were easy to fill and the shallow light held the oil well. The non-diving torch needed some inner tube, but was tight after that.
It's a shame that the beam is so badly affected, one £8 and one £13 bright diving torches would have been great.
If anyone needs about 3l of baby oil let me know
