<div dir="ltr">appreciate the feedback guys! </div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Dec 20, 2024 at 5:49 PM Alec Smyth via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">Good point, I agree!<br id="m_-7900106441185396839lineBreakAtBeginningOfSignature"><div dir="ltr"><br></div><div dir="ltr"><br><blockquote type="cite">On Dec 20, 2024, at 5:48 PM, Alan James via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div id="m_-7900106441185396839yiv6593033290"><div>Great advice thanks Alec.<div>So in Rick's case, where he is machining the side rather than the faces, the crazing won't matter.</div><div>Alan<br clear="none"><br clear="none"><div id="m_-7900106441185396839yiv6593033290ymail_android_signature"><a rel="nofollow noopener noreferrer" shape="rect" id="m_-7900106441185396839yiv6593033290ymail_android_signature_link" href="https://mail.onelink.me/107872968?pid=nativeplacement&c=US_Acquisition_YMktg_315_SearchOrgConquer_EmailSignature&af_sub1=Acquisition&af_sub2=US_YMktg&af_sub3=&af_sub4=100002039&af_sub5=C01_Email_Static_&af_ios_store_cpp=0c38e4b0-a27e-40f9-a211-f4e2de32ab91&af_android_url=https://play.google.com/store/apps/details?id=com.yahoo.mobile.client.android.mail&listing=search_organize_conquer" target="_blank">Yahoo Mail: Search, organise, conquer</a></div> <br clear="none"> <blockquote style="margin:0px 0px 20px"> <div id="m_-7900106441185396839yiv6593033290yqt59189"><div style="font-family:Roboto,sans-serif;color:rgb(109,0,246)"> <div>On Sat, 21 Dec 2024 at 11:19 am, Alec Smyth via Personal_Submersibles</div><div><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:</div> </div> <div style="padding:10px 0px 0px 20px;margin:10px 0px 0px;border-left:1px solid rgb(109,0,246)"> <div id="m_-7900106441185396839yiv6593033290"><div dir="ltr">Hi friends,<div><br clear="none"></div><div>I just got a call from Greg, so took the opportunity to ask him about this question of whether or not to anneal the front viewport after machining it to the lower diameter. I was correct about "any time you machine, you anneal" being the proper thing to do, but he also confirmed that Kittredge never annealed his viewports (which were all tested to 500'). In his opinion, given the modest depths we operate at, we're fine without annealing. But what surprised me was the nature of the downside. He didn't think machined-but-not-annealed viewports would fail prematurely, but he said they would craze prematurely with exposed to the sun. What happens is that the machining heats just a very thin layer of acrylic, at the surface. When you heat those molecules, they contract 2-3 percent, and that puts stress between the thin layer of surface molecules and the ones beneath. The crazing you see when acrylic has been exposed to the sun is cracks between the surface molecules and those below. If there is built in stress between those layers, then the UV-induced cracks appear much more easily.</div><div><br clear="none"></div><div>He also reminded me of something else. Rick, when you pot the window, be sure to wipe off the excess Sikaflex, rather than cut it off with a razor. If you cut off the excess, there's a high chance of scoring the surface. That, particularly on the inside face of the window that is going to be under tension, is far more concerning than not annealing as far as affecting failure depth.</div><div><br clear="none"></div><div>Best,</div><div>Alec</div></div><br clear="none"><div><div dir="ltr">On Thu, Dec 12, 2024 at 4:27 PM Rick Patton via Personal_Submersibles <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Thanks Hank, I'll check it out.<div><br clear="none"></div><div>Rick</div></div><br clear="none"><div><div dir="ltr">On Wed, Dec 11, 2024 at 12:54 PM hank pronk via Personal_Submersibles <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-family:Helvetica,Arial,sans-serif;font-size:13px"><div></div>
<div dir="ltr">Rick, </div><div dir="ltr">I have a concern about using a sealant for your front port. You mention that you welded up an o-ring groove and thats why you want to use a sealant. If you did not have the seat machined after welding and smoothing the weld, then it may be distorted. Using a sealant to make up for the distortion may be a bad idea. The sealant is not going to transfer the load evenly to the seat, given the softness. If that is the case, I would have it machined again, even if it means cutting the frame out. That solves both problems. Welding it back in would be a breeze for you. Cut it out from the inside to avoid burning interior stuff. I have built a wood bulk head in Gamma to protect the interior when I cut the front off.</div><div dir="ltr">Hank</div><div><br clear="none"></div>
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On Wednesday, December 11, 2024 at 07:15:41 AM MST, Jon Wallace via Personal_Submersibles <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:
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<div dir="ltr">We should perhaps seek some clarification from Greg if he's willing to guide us. I had a conversation with him about Kittredge annealing and he told me Kittredge never annealed any of his viewports. </div><div dir="ltr"><br clear="none"></div><div dir="ltr">Stachiw was pretty adamant about annealing in his book. Like Hank, I do seem to recall some restrictions regarding annealing multiple times although I don't recall if it's a single time or a different schedule as Dan suggested and I don't have my Stachiw book with me right now to check. There is a rather obscure one sentence statement by Stachiw in his book in which he says any annealing is better than none. This suggests to me that while adhering to the strict annealing schedule is ideal, if it cannot be met benefits will still be derived from a looser schedule.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">Jon</div><div dir="ltr"><br clear="none"></div><div dir="ltr"><br clear="none"></div><div><br clear="none"></div>
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On Tuesday, December 10, 2024 at 11:59:14 PM EST, Alec Smyth via Personal_Submersibles <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:
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<div><div id="m_-7900106441185396839yiv6593033290m_-2038493006952079557m_1958788022519133853yiv6096408718ydp20bc3ce8yiv7090979291"><div><div dir="ltr">Hank, what you're proposing sounds totally logical to me. However, I have asked Greg this very question in the past (whether we really have to anneal a viewport.) I'm not sure what the underlying causality is, but he has enough professional experience in the field that I just take his word for it. "You need to re-anneal it whenever any machining has been done on a viewport." Annealing is pretty straight forward. <div><br clear="none"></div><div>I'm currently working on forming acrylic headlight covers and windows for an antique car restoration. It's a new skill I'm trying to develop, so fortunately I'm not making anything safety-critical like viewports. But one interesting detail is that Greg strongly recommended annealing even for this, because it'll make the covers and windows less likely to crack (there could be stresses caused by mounting screws or flying pebbles, for instance.) He had two basic points he stressed for the things to last:<div><br clear="none"></div><div>1) That not all acrylic was equal. The only one he will use is "cell cast" acrylic, and he warned me emphatically to stay away from the cheap stuff which can be referred to as extruded or "continuous cast." I know this has not been mentioned on this thread, but I bring it up because it seems to be key information.</div><div>2) Annealing</div><div><br clear="none"></div><div>Next time I speak to him, I'll ask about machining with light passes and coolant.</div></div><div><br clear="none"></div><div>Best,</div><div>Alec</div></div><br clear="none"><div><div id="m_-7900106441185396839yiv6593033290m_-2038493006952079557m_1958788022519133853yiv6096408718ydp20bc3ce8yiv7090979291yqt27263"><div dir="ltr"><br clear="none"></div></div></div></div></div></div>
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