I am a researcher working to develop a hydrogen fuel system for use in a specialized internal combustion engine. The biggest challenge from an engineering standpoint with a project such as this is the inherently volatile nature and small size of the hydrogen molecule. My research has led me in a variety of different directions and provided a great deal of information about hydrogen's properties as an element and as an energy source, however after over two years of research, I have thus far found no information whatsoever on what specific manufacturing techniques are employed to ensure minimal leakage, if any.

Any constructive input regarding the formatting or content of this question would be greatly appreciated, as this is my first post on this site.

  • $\begingroup$ @foolishmuse Thank you very much for the feedback, I found it very enlightening. So just to be clear, you stick with neoprene in both your electrolyzers and your valve systems? And are there any specific suppliers of neoprene that you might recommend? Thanks. $\endgroup$
    – CJL
    Aug 21 '20 at 1:08

I am also in the hydrogen business and yes this is a big problem. We create gas by electrolysis on 16 stainless plates, each about 20cm x 20cm. We use neoprene gaskets about 1cm wide and 2.2mm thick, in between each of the plates to maintain proper separation. All tightened with 8 bolts. For fittings, we coat the threads with Sikaflex adhesive. Even the quality of the neoprene is important; if the neoprene is not perfectly uniform, it reduces our gas production and can lead to leaks. In cold weather the neoprene will shrink and cause major leaks, so it's important that you put the unit in the fridge before final tightening of the bolts. We have tried many other gasket materials and many other adhesives, but have settled on this.

  • $\begingroup$ Why, of all elastomers, the rather old-fashioned neoprene? I used to be a material development engineer, on specialty, engineering elastomers. $\endgroup$
    – Gert
    Aug 20 '20 at 20:48
  • $\begingroup$ @Gert We often say that we can't find any science in this, only magic. Neoprene just seems to work and all the other materials we've tried, even with adhesive added, don't. Keep in mind that we have KOH in the water, so we need something that doesn't degrade over the long term. $\endgroup$ Aug 20 '20 at 20:51
  • $\begingroup$ My first choice would be EPDM but it might be a little poorer on adhesion than CR. EPDM resists KOH basically forever. $\endgroup$
    – Gert
    Aug 20 '20 at 21:05
  • $\begingroup$ @Gert We tried EPDM. My engineer recalls that it went too soft at higher temperatures above 50C and leaked. $\endgroup$ Aug 20 '20 at 21:10
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    $\begingroup$ Hmmm... that's a problem of formulation. Anyroads... good luck with the hydrogen! $\endgroup$
    – Gert
    Aug 20 '20 at 21:13

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