<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Alec,</div><div>good idea using the o-ring on top of the glass. </div><div>I have been searching on sight glass / gauge glass sites to find the best</div><div>gasket for under the lens. PTFE (teflon) seems to be well thought of in</div><div>high temperature applications. Not sure of the recommended thickness</div><div>but one manufacturer selling site glass spares had 1/16 & 3/32" gaskets.</div><div>It is really a miniature view port in construction so I guess the gasket on </div><div>our view ports would be relatively thin if you scaled them down to a light</div><div>housing size.</div><div>Cheers Alan </div><div><br><div>Sent from my iPad</div></div><div><br>On 19/04/2017, at 10:06 PM, Alec Smyth via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">For under the lens I have no gasket. I think the main reason I was breaking lenses on one light but not the other was that in the problem one the cavity for the lens was ever too small and the lens was squeezed by it. The problem seemed to be resolved by re-machining the cavity to enlarge it by just a few thousandths. If that had not solved it, my next step was going to be adding a gasket under the lens. It would need to be very thin, and I was planning to cut it from disposable gloves. But apparently no need. As the top gasket I use the O ring itself. I've chamfered the top edge of the lens cavity and use a triangular sealing pattern for the o ring.<div><br></div><div>Best,</div><div><br></div><div>Alec</div><div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Apr 18, 2017 at 10:28 PM, Alan James via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="color:#000;background-color:#fff;font-family:Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px"><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2272"> Cliff & Alec,</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2271">just ordering 20 tempered borosilicate lenses at $2-50 each including postage!</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2305">They will go in the pressure chamber, so I'll know whether I got good value.</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2325">Just wondering what you guys used as gaskets under the lens.</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2324">I did have an o-ring under the acrylic lens but are putting a gasket under the glass.</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2342">I have an o-ring in the bore of the lens housing but would like my gasket to be a </div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2417" dir="ltr">secondary seal as well as seat.</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2416" dir="ltr">Alec, with your experience of lenses breaking, I am looking at a suitable thickness</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2415" dir="ltr">of neoprene or similar for the top gasket that I can compress to half it's thickness </div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2434" dir="ltr">when bolting the housing together. This will give me a bit of machining tolerance.</div><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2465" dir="ltr">see attachment</div><span class="HOEnZb"><font color="#888888"><div id="m_5828144804550492195yui_3_16_0_ym19_1_1492567889675_2448" dir="ltr">Alan</div></font></span></div></div><br>______________________________<wbr>_________________<br>
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