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<div>Alan,</div><div><br></div><div>I like the idea of epoxying the transition between bare wire and insulation. I think that's a good basic rule to follow. I forgot about it this time but will follow it next time. As far as potting the entire volume of the PVC housing, I have enough confidence in the housing that I just didn't think I needed to. Even in the worst case possible, failure and water entering through the wire insulation, it's not like that water is going to immediately seep the ten feet of wire that will be involved...and even if it managed to do that, it wouldn't be a flooding threat that would prevent me from surfacing. However, point taken regarding flooding and damage to electronics and wiring. It's easy to say "it's only $30" but that does add up eventually into real money. I have already learned that. I kept adding sensors to my SCM project over a period of weeks and months. Each sensor by itself was pretty cheap and I thought, gee why isn't everyone doing this. It wasn't until I added everything up that I realized I had about $1000 in parts alone invested in it.</div><div><br></div><div>Regarding overall pressure failure at the wire entrance sealed with epoxy, I think taking into account practical application is reasonable. At maximum depth, I will be around 300 psi, however the "area" of epoxy exposure is less than .049 inches (1.2mm) which equates to withstanding about 14.7 psi. It's obvious that my method certainly would not survive thousands of PSI, but it doesn't have to. You mentioned Doug Jackson having many failures with his DIY penetrators and I've seen those videos also. My impression is that many of his failures were self inflicted, for example using the 5-minute epoxy product with the needle like dispenser that mixes automatically. I've used that same product (once) and found that it didn't mix the two parts nearly enough for a strong bond. That particular product is meant for the home owner who wants to repair a tea cup. Ultimately, even with that he was at least once able to get a good enough seal for 2000 psi. So I'm not surprised that Hank has had better luck with his penetrators using better epoxy and mixing practices. </div><div><br></div><div>Jon</div><div><br></div><div><br></div>
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On Thursday, June 13, 2019, 06:02:59 PM EDT, Alan via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div id="ydpbdd9058dyiv8177754284"><div><div></div><div>Jon,</div><div>I like the choice of PVC & think it would be quite strong, & if you</div><div>potted inside, even stronger.</div><div>I am paranoid as I have destroyed a lot of electronics with salt water.</div><div>And had water sucked up inside the wire jackets for a metre due to</div><div>heating & cooling.</div><div>Maybe on the compass project strip a section of the wire going through</div><div>the epoxy & use one of the techniques in the link to improve the PVC</div><div>bond X 3 times. And go over the board with the epoxy. Was doing this </div><div>on my LED driver last night.</div><div>Alan</div><div><br clear="none"></div><div><img id="ydpbdd9058dyiv81777542848B00DB32-E1C8-4501-AD57-2FF4A082620E" src="cid:zgXAnLw9WKhw0T306Sr1" alt="image1.JPG" data-inlineimagemanipulating="true" style="width: 100%; max-width: 800px;"><br clear="none"></div><div class="ydpbdd9058dyiv8177754284yqt3776722415" id="ydpbdd9058dyiv8177754284yqt90046"><div><br clear="none">On 14/06/2019, at 9:32 AM, Jon Wallace via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div class="ydpbdd9058dyiv8177754284ydp4819e27cyahoo-style-wrap" style="font-family:times new roman, new york, times, serif;font-size:16px;"><div></div>
<div><span><span style="color:rgb(0, 0, 0);font-family:times new roman, new york, times, serif;font-size:16px;">Alan, all great points and I wouldn't argue against them. You may be right about the epoxy/pvc adhesion, and as usual the internet isn't much help. I can find as many "don't do it" as "it works fine" opinions out there. <span><span style="color:rgb(0, 0, 0);font-family:times new roman, new york, times, serif;font-size:16px;">I should have scuffed it up a bit though, that would have helped with adhesion. In the past I have fabricated my own "blue globe" fittings out of brass compression fittings but I wanted all plastic so I wouldn't have to worry about decay of the brass by salt-water. </span></span>I mentioned a couple of times in the video that this was a non-critical component but maybe should have impressed that a bit more on the viewer. PVC certainly would not be my choice for a critical application.</span></span></div><div><span><span style="color:rgb(0, 0, 0);font-family:times new roman, new york, times, serif;font-size:16px;"><br clear="none"></span></span></div><div><span><span style="color:rgb(0, 0, 0);font-family:times new roman, new york, times, serif;font-size:16px;">Jon</span></span></div><div><span><span style="color:rgb(0, 0, 0);font-family:times new roman, new york, times, serif;font-size:16px;"><br clear="none"></span></span></div><div><br clear="none"></div>
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On Thursday, June 13, 2019, 08:22:08 AM EDT, Alan via Personal_Submersibles <<a shape="rect" href="mailto:personal_submersibles@psubs.org" rel="nofollow" target="_blank">personal_submersibles@psubs.org</a>> wrote:
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<div><div dir="ltr">Jon,<br clear="none"></div><div dir="ltr">that was one of the most comprehensive "How to" videos I've seen.<br clear="none"></div><div dir="ltr">Have one of those compasses so will emulate that.<br clear="none"></div><div dir="ltr">I have reservations about epoxy sealing the wires though.<br clear="none"></div><div dir="ltr">I did a lot of experiments with glues & PVC wire jackets & found a lot of<br clear="none"></div><div dir="ltr">the glues disappointing. I found one product specifically for PVC boats<br clear="none"></div><div dir="ltr">that stood out.<br clear="none"></div><div dir="ltr">I have mentioned before that I potted a couple of wires for 1" in to a WD40<br clear="none"></div><div dir="ltr">filled housing & the WD40 just ran out between the epoxy & wire jacket<br clear="none"></div><div dir="ltr">without pressure. <br clear="none"></div><div dir="ltr">Under pressure I would guess that the PVC jacket would be more compressible<br clear="none"></div><div dir="ltr">than the epoxy resin around it & would tear away from it, letting water in.<br clear="none"></div><div dir="ltr">Suggest epoxying the whole board both sides & the wires where they are <br clear="none"></div><div dir="ltr">soldered on, in case of water egress.<br clear="none"></div><div dir="ltr">I have strong reservations about the epoxy sticking to the PVC pipe also.<br clear="none"></div><div dir="ltr">I would be interested in others opinions on this as potting wires is <br clear="none"></div><div dir="ltr">something we are doing a lot of.<br clear="none"></div><div dir="ltr">Alan<br clear="none"></div><div dir="ltr"><br clear="none"></div><div dir="ltr">_______________________________________________<br clear="none"></div><div dir="ltr">Personal_Submersibles mailing list<br clear="none"></div><div dir="ltr"><a shape="rect" href="mailto:Personal_Submersibles@psubs.org" rel="nofollow" target="_blank">Personal_Submersibles@psubs.org</a><br clear="none"></div><div dir="ltr"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" rel="nofollow" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
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</div></div></blockquote></div><blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>Personal_Submersibles mailing list</span><br clear="none"><span><a shape="rect" href="mailto:Personal_Submersibles@psubs.org" rel="nofollow" target="_blank">Personal_Submersibles@psubs.org</a></span><br clear="none"><span><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" rel="nofollow" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br clear="none"></div></blockquote></div></div><div class="ydpbdd9058dyqt3776722415" id="ydpbdd9058dyqt12632">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a shape="rect" href="mailto:Personal_Submersibles@psubs.org" rel="nofollow" target="_blank">Personal_Submersibles@psubs.org</a><br clear="none"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" rel="nofollow" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
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