7 replies to this topic

[curtisleo]

Anyone know what that small hydrogen gas scrubber pellet is made of. Typically found in flashlights?

Curtis

[Paul Kay]

I've wondered this myself but few manufacturers seem to supply these now.I suspect its a catalyst and chemical combination?

[curtisleo]

Been searching around but it looks like a compressed carbon type. I did some rough calculations and, if hydrogen is being discharged, that small pellet is not going to help at all. A blow-out disc would be the best option.

A huge buildup of hydrogen inside a flashlight would typically come from water leaking in and shorting out.

[segal3]

You misunderstand the purpose of the pellet.

When batteries are charged or discharged, they have the means to emit small amounts of hydrogen gas (especially prevalent with lead-acid batteries). Normally it's not an issue, because the area the batteries are charging or discharging is not sealed. In underwater lights, however, that is not the case.

You do not want gradual buildup of this gas, so the pellet removes the small amount of the hydrogen.

I'm still confused why this was posted in DIY...

~Matt Segal

[DeepThinkers]

DIY? ...I can easily see why we may want to locate an inexpensive source for the pellet material for use in our special projects involving batteries.

Besides ...DIYers as a group like to think in a creative way about *anything* :)

Bill

[Craig Ruaux]

AFAIK: The catalyst material is platinum. Not very much of it... but platinum none the less.

And roll-your own platinum is not exactly cheap

[Paul Kay]

Ahhhh. Now I have a small piece of Platinum wire ( an inch bought for 5 shillings when I was a schoolboy). Now all I need is a hammer and some muscle I suppose.......

[bvanant]

It isn't clear that the material is either a catalyst or a platinum group metal. Metal hydrides can also be used to trap H2 at room temp and pressure and some can absorb 5 to 6% by weight of H2. If it is a catalyst at RT then it is one of the Pt group metals, probably coated on the surface of some alumina. It also might be simply graphite powder that does some adsorption. Now you have gotten me curious, time to go to the lab, but first I need to find a lamp that has one.
Bill