This month it’s compressed into one big tip
Big bang theory
Gareth Pemberton suggests I publish a correction to the suggestion that tank leaks can be tested by using compressed air (Fixes, April) saying it is ‘extremely dangerous and can cause injury or fatalities’.
A professional engineer in the oil and gas industry, Gareth has come across several such incidents, he says. ‘It is possible to store high amounts of pressure energy in the tank, even with a low-capacity compressor. Air is compressible and will continue to expand if the tank ruptures. This can cause sharp fragments of metal to fly out in the resulting explosion.’
I understand Gareth’s concerns, but the letter did say that the breather should be ‘taped over’. If I check for leaks underwater I use a cycle pump, as it shouldn’t take much pressure to create a stream of bubbles and a compressor increases pressure too fast to monitor. I’ve never heard of a tank exploding, but have seen one alter its shape.
Blowing dents out of trials bike tanks was common practice, but I recall speedway rider Malcolm Simmonds telling me he’d done it once successfully, or so he thought until he tried to remove the tank and found the tunnel had moulded itself around the frame! Handle with care.
Cycle pump pressure was enough to reveal a Scott rad leak