<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px"><div><span>Alan,</span></div><div id="yui_3_16_0_ym19_1_1498039990369_3168" dir="ltr"><span id="yui_3_16_0_ym19_1_1498039990369_3255">I wondered about the oil under such pressure behind air also but then thought of situations in real life where this happens. A hydraulic system can very easily have an air pocket until it works itself out. For instance when you change a cylinder it takes a bit of time to work the air out and it is under full pressure and in many cases higher than 3,000 psi. My concern with what you described is the volume of air at the top of the chamber, but your your chamber is pretty darn bullet proof. I use air to pressurize my chambers with water and figure the volume of air in the 36 inch long 1\4 dia hose is not going to amount to anything. I always have a barrier between me and the chamber, but my chamber is home made. I am not sure why you want all the mess with oil, can't you just drain it and wipe it down with WD-40. It is a clever idea but I see a big mess to clean up. </span></div><div id="yui_3_16_0_ym19_1_1498039990369_3168" dir="ltr"><span>Hank</span></div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Wednesday, June 21, 2017 2:40 AM, Beram Mahmoud via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv1782122214"><div><div style="font-family:Verdana;font-size:12.0px;"><div>
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<div>Hello,</div>
<div> </div>
<div>well why not using the idea of hydroforming :<br clear="none">
http://www.colinfurze.com/hydroforming.html</div>
<div>Use a presssure washer with 200 bar and you got your 2900 psi...</div>
<div>By doing so you have no issue with expanding gases.</div>
<div> </div>
<div>Best regards</div>
<div> </div>
<div>Beram</div>
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<div style="margin:0 0 10px 0;"><b>Gesendet:</b> Mittwoch, 21. Juni 2017 um 09:40 Uhr<br clear="none">
<b>Von:</b> "Stephen Fordyce via Personal_Submersibles" <personal_submersibles@psubs.org><br clear="none">
<b>An:</b> "Personal Submersibles General Discussion" <personal_submersibles@psubs.org><br clear="none">
<b>Betreff:</b> Re: [PSUBS-MAILIST] Pressure Test Chamber</div>
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<div>Hi Hugh & Alan,</div>
<div>Good point to consider, but it would depend on the flashpoint of the oil. SCUBA compressors do the exact combination of pressure/air/oil and don't explode. Diesel engines do too - sort of, anyway. Mineral oil designed for compressors would be a good option although pricey (AU$200 for 20L recently). Shell Corena P150 mineral oil is what I use.</div>
<div> </div>
<div>High pressure air is a mechanical hazard to be considered in and of itself. I'd highly recommend installing a relief valve (or device) on any test chamber or other vessel.</div>
<div> </div>
<div>Cheers,</div>
<div>Steve</div>
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<div class="yiv1782122214gmail_quote">On Wed, Jun 21, 2017 at 2:28 PM, Hugh Fulton via Personal_Submersibles <span><<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:
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<div class="yiv1782122214MsoNormal"><span style="color:rgb(31,73,125);font-family:Calibri , sans-serif;font-size:11.0pt;">Alan,</span></div>
<div class="yiv1782122214MsoNormal"><span style="color:rgb(31,73,125);font-family:Calibri , sans-serif;font-size:11.0pt;">Never pressurise oil with air to those pressures. An explosion waiting to happen. Oxygen partial pressures!!</span></div>
<div class="yiv1782122214MsoNormal"><span style="color:rgb(31,73,125);font-family:Calibri , sans-serif;font-size:11.0pt;">If you want to do it use nitrogen.</span></div>
<div class="yiv1782122214MsoNormal"><span style="color:rgb(31,73,125);font-family:Calibri , sans-serif;font-size:11.0pt;">Hugh</span></div>
<div class="yiv1782122214MsoNormal"><span style="color:rgb(31,73,125);font-family:Calibri , sans-serif;font-size:11.0pt;"> </span></div>
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<div class="yiv1782122214MsoNormal"><b><span style="font-family:Tahoma , sans-serif;font-size:10.0pt;">From:</span></b><span style="font-family:Tahoma , sans-serif;font-size:10.0pt;"> Personal_Submersibles [mailto:<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles-bounces@psubs.org" target="_blank" href="mailto:personal_submersibles-bounces@psubs.org">personal_submersibles-bounces@psubs.org</a>] <b>On Behalf Of </b>james cottrell via Personal_Submersibles<br clear="none">
<b>Sent:</b> Wednesday, 21 June 2017 3:34 PM<br clear="none">
<b>To:</b> Personal Submersibles General Discussion<br clear="none">
<b>Subject:</b> Re: [PSUBS-MAILIST] Pressure Test Chamber</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;font-family:Verdana , sans-serif;font-size:10.0pt;">Alan,</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;font-family:Verdana , sans-serif;font-size:10.0pt;"> </span></div>
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<div id="yiv1782122214m_-331964700394927430yui_3_16_0_ym19_1_1498015667083_3751">
<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;font-family:Verdana , sans-serif;font-size:10.0pt;">Pressure testing that high needs to be done with liquid not gas. High pressure air is VERY dangerous. A pressure washer pump using water would be a safer choice.</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;font-family:Verdana , sans-serif;font-size:10.0pt;">Greg</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><b><span style="color:black;font-family:Arial , sans-serif;font-size:10.0pt;">From:</span></b><span style="color:black;font-family:Arial , sans-serif;font-size:10.0pt;"> Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none">
<b>To:</b> <a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a><br clear="none">
<b>Sent:</b> Tuesday, June 20, 2017 9:01 PM<br clear="none">
<b>Subject:</b> [PSUBS-MAILIST] Pressure Test Chamber</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;"> </span></div>
<div id="yiv1782122214m_-331964700394927430yui_3_16_0_ym19_1_1498015667083_3774">
<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">I am making a plastic container to fill with water & stand inside my</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">pressure chamber. There is a gap between the wall of the container</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">& the chamber which I intend to fill with oil. There will be about an</span></div>
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<div id="yiv1782122214m_-331964700394927430yui_3_16_0_ym19_1_1498015667083_3773">
<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">inch of air at the top of the chamber & I'm using a scuba tank to</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">pressurise the unit up to 3000psi.</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">Will car engine oil do to fill the gap between my plastic container &</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">the chamber wall, or do I need to go with a hydraulic fluid.</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">Am using the plastic container to keep water from rusting my test</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">chamber. (Aussie Steve's idea)</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">Cheers Alan</span></div>
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<div class="yiv1782122214MsoNormal" style="background:white;"><span style="color:black;">Sent from my iPad</span></div>
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