<html><head></head><body><p dir="ltr">In North America, your scuba tank threads will be 3/4-14 NPS, or 7/8-16 UNF for some higher pressure cylinders intended for working pressures above 3500 psi. These are both straight thread forms, intended to carry mechanical load but not to seal. The seal is provided by an O-ring in both cases. No sealant or Teflon tape should be used. The O-ring is slightly higher durometer than common (I think 90?). I always use Viton o-rings lubricated with oxygen compatible grease, but this is only strictly necessary for oxygen service. Many people do not lube this ring at all, but I prefer to always lube o-rings, even in "static" service. There may be an ideal torque, but I don't know what it is. Check with the valve manufacturer. I always just bump them a bit beyond hand tight.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On November 14, 2016 7:16:33 AM MST, James Frankland via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div dir="ltr"><div>Does anyone know if there is any specific torque required to fit a scuba tank pillar valve for an ordinary 220bar air tank? Any ptfe or thread sealant required?</div><div><br />Thanks<br />james</div></div>
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