Do ghetto tubeless inflators actually ever go bang?

larkim

Started making one up last night and was very very fearful of a nasty bang, so didn't really get to putting serious pressure into the bottle.

I know all the guides warn of the risks of a big bang, but has anyone experienced it? What is the major hazard - noise or shrapnel?

rockmonkeysc

If you're worried, you can do a safer trial inflation. Fill the bottle to about 90% with water and then pressurise it. This way if it does go bang, the water will damp down the explosive force and noise. Thats how I used to test pressure vessels at hundreds of bar of pressure.

ddraver

I don't know but I don't expect there'd be much shrapnel. I ve ballsed up putting tubes in road tyres before and they ve popped at 100+ psi and it's a hell of a bang but nothing hugely serious happens

larkim

Water sounds a very sensible option, I suppose the "worst" that could happen is one of the presta valves come shearing out of the top with a body part in front of it. Need to get my track pump fixed first anyway (anyone know how to re-assemble a blackburn head, I can't work out whether my kids have pulled it apart and lost something, or it's just knackered somehow - got a replacement head on the way, but I don't like not knowing what's wrong with it!)

drlodge

The water doesn't so much damp down the explosion, its simply that the amount of energy is dependent on the volume of air and the pressure. Smaller volume of air (as water doesn't compress) = less energy.

I wouldn't expect these things to go "bang", rather they might leak air first or at least give some kind of warning.

njee20

ddraver wrote:

I don't know but I don't expect there'd be much shrapnel. I ve ballsed up putting tubes in road tyres before and they ve popped at 100+ psi and it's a hell of a bang but nothing hugely serious happens

Shrapnel not from the tyre, but the inflator...

The Rookie

I checked my coke bottle to 80psi and it was fine, I find I only need to use about 40psi to inflate a tyre.

crazymac680

I've wrapped mine in black tape and put it to 120 for a really stubborn tyre. Normally 80 has been enough for me. I've had the hose pop off a couple of times. Really have me a fright. Zero damage.

larkim

Used successfully in anger yesterday to get a couple of tyres up. No bangs. The tube I've got which needs clamping is not ideal (too short, came off an old tube of expanding foam), but it works.

As this was me losing my tubeless virginity, I'm quite pleased I got two tyres up with relatively little fuss and my own hand build inflator on low quality Decathlon rims.

dirkpitt74

Just found This Article on Pop bottle pressures. Interesting that in 'normal' use a full bottle of pop is around 50psi and can go up to 100psi if left in a hot car.
According to the article bottles seem to be able to withstand around 150psi.