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#1
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
If you've been paying attention, you know I've dropped my rudder and have
been removing prior attempts to epoxy pits in the shaft - done in a convoluted, upside-down manner, inside the boat - which turned out badly. With the rudder out, I have access to it conveniently, to do it up right (well, as best as possible in that it can't be sent off for grinding, rewelding, and machining to round again). I believe I have all the prior epoxy out. Some of the pits have tunnels up or down, too, which, as I worked them out with the pick, displayed remnants of prior packing material. Not so good. The good news is that nearly everywhere I managed to pick off shows very bright under the old epoxy, so it's clean (or will be when I use a brush and acetone to remove all solubles which may be hiding on the surface, and which would impede bonding). The area covered by the packing gland has minimal reduction in diameter - mostly 2-5, and at worst, ~8 thousandths of an inch (out of 2"). However, I'd like not to have even that, if I can avoid it... Ed. Note: I started this last night, but abandoned it for a while so I could run up to Vero to take my wife out for dinner on our 9th anniversary. In the meantime, I THINK I've answered my own question, below, which I'll show at the bottom, but in case there's a better answer, leave this he Which leads me to ask about how to - in this group's collective wisdom - best sand the Devcon Plastic Steel Epoxy I'll put on, using the top and bottom of (up and down from) the newly epoxied area (Plastic Steel is touted as machinable, drill-and-tappable and otherwise as hard as steel when it's fully set) as a guide, to build that back out, but still maintain roundness. Any variance wouldn't do the packing any good, I don't think, regardless of whether it's smooth. Sanding the epoxy when it's green should allow me to have minimal, if any measurable, impact (from sanding away good metal) on the unpitted sections of the shaft, I believe. Even if that weren't true, it is of no consequence in that those areas do nothing related to water intrusion, and that amount isn't relevant to strength. Fortunately, after I re-install the rudder and shoe, I have complete access to the rudder tube/packing gland before I reassemble the steering gear (which, of course, will require the packing nut be slid on before that). I'll use feeler guages to exactly (well, as exactly as I can) center the tube in the shaft, using a jack stand to support the weight of the rudder itself, hanging off the shaft (which would put pressure on the aft portion of the shaft), but without raising it from the shoe. That will allow me to use the very substantial steering setup (see "drop it" in the "third try" section of the rudder gallery for the disassembly of that), with its two heavy delrin bushings, to keep it centered. My steering is Scotch Yoke, which is two arms (push-pull), so I won't have any leverage to the side when applying turning forces. So, my repair should be under the least possible stress on the packing gland when it's finished - or, at least, that's my story, and I'm sticking to it :{)) So, I have my repair sequence thought out. Any ideas about how to manage sanding of the epoxy excess from a perfect 2" round outcome? Pix to this point start at http://justpickone.org/skip/gallery/...+Old+Epoxy+Out Ed. Note: So, that's what I'd had last night. In the meantime, I came up with various sorts of pipe solutions - 2" PVC, a 2" nipple, and, today, as I was wandering in the yard and happened upon the welder here, I realized that he probably used 2" aluminum pipe in his work. He confirmed that he did, and that 2" dimension was ID, and has offered me a cutoff. I don't think that I can get it down the shaft, and if I could, there wouldn't be room for sandpaper's thickness, even if I could figure out how to adhere it. I'd first test it to see how exact it was, of course; if it's very slightly oversized, that changes matters, as, of course, its being slightly undersized would, in my thinking. However, I believe that if I cut it lengthwise at slightly less than exactly half, I will have a small section which I can carefully ram/wooden-hammer (lengthwise) over the shaft, thus expanding it slightly so as to allow for sandpaper's thickness. This would solve both the straight line challenge I posed above, as well as enhance the ability to end up with a round finished product, by going not only up and down the shaft, but around it with this slightly-more-than-half pipe. If I can't make it expand enough, I could use the slightly-less-than-half-pipe nearly as well to the purpose. Both would be amply stout to preserve a straight line, my original thought/challenge, from good material over pit repair to good material on the other side, but would have the advantage of a curvature closely matching that of the shaft. So, back to all my begs in one ask-it, are there any better ideas? And, if this idea is da bomb, what's the best way to manipulate this sanding shoe to achieve the best results, in your collective opinion? L8R, y'all Skip, working on the boat -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog When a man comes to like a sea life, he is not fit to live on land. - Dr. Samuel Johnson |
#2
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Tue, 24 Apr 2012 11:55:25 -0400, "Flying Pig"
wrote in part: Ed. Note: So, that's what I'd had last night. In the meantime, I came up with various sorts of pipe solutions - 2" PVC, a 2" nipple, and, today, as I was wandering in the yard and happened upon the welder here, I realized that he probably used 2" aluminum pipe in his work. He confirmed that he did, and that 2" dimension was ID, and has offered me a cutoff. I don't think that I can get it down the shaft, and if I could, there wouldn't be room for sandpaper's thickness, even if I could figure out how to adhere it. I'd first test it to see how exact it was, of course; if it's very slightly oversized, that changes matters, as, of course, its being slightly undersized would, in my thinking. However, I believe that if I cut it lengthwise at slightly less than exactly half, I will have a small section which I can carefully ram/wooden-hammer (lengthwise) over the shaft, thus expanding it slightly so as to allow for sandpaper's thickness. This would solve both the straight line challenge I posed above, as well as enhance the ability to end up with a round finished product, by going not only up and down the shaft, but around it with this slightly-more-than-half pipe. If I can't make it expand enough, I could use the slightly-less-than-half-pipe nearly as well to the purpose. Both would be amply stout to preserve a straight line, my original thought/challenge, from good material over pit repair to good material on the other side, but would have the advantage of a curvature closely matching that of the shaft. So, back to all my begs in one ask-it, are there any better ideas? And, if this idea is da bomb, what's the best way to manipulate this sanding shoe to achieve the best results, in your collective opinion? L8R, y'all Skip, working on the boat Skip, I really hate to throw in a very negative note, but... I've used that Devcon commercial stuff quite a lot. You really don't realize just how difficult that stuff is to sand. Imagine you welded around to build up the shaft and then take that metal down with sandpaper. That's pretty much how the Devcon is. When they say can be "machined", they do mean machined with a lathe, milling machine, drill, etc. One thought. Take that 2" drop off and verify it'll fit over the shaft snugly, even, in fact preferably if it has to be heated a bit. Camfer one end. Apply the Devcon to the shaft, letting it build up a bit. Coat the inside of the drop off with some kind of mold release. Heat it up and slide / hammer it over the area and fasten in place. Remove all the Devcon squeezed out. After it's cured, hammer and cuss to get the drop off "mold" off. Rick |
#3
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
"Rick Morel" wrote in message
... Skip, I really hate to throw in a very negative note, but... I've used that Devcon commercial stuff quite a lot. You really don't realize just how difficult that stuff is to sand. Imagine you welded around to build up the shaft and then take that metal down with sandpaper. That's pretty much how the Devcon is. When they say can be "machined", they do mean machined with a lathe, milling machine, drill, etc. One thought. Take that 2" drop off and verify it'll fit over the shaft snugly, even, in fact preferably if it has to be heated a bit. Camfer one end. Apply the Devcon to the shaft, letting it build up a bit. Coat the inside of the drop off with some kind of mold release. Heat it up and slide / hammer it over the area and fasten in place. Remove all the Devcon squeezed out. After it's cured, hammer and cuss to get the drop off "mold" off. Rick Hi, Rick, and group, I just got off a long phone call with Devcon, before seeing this. This stuff (Devcon PN 62345, AKA Versachem 47709 for automotive and the like) hardens from the outside in, and as a result I'd identified the problems you cite. While I like the idea of the slicer, and it basically is what the SKF folks have one do if the surface being repaired is like mine, except that the epoxy not only fills underneath, but (also) secures the sleeve, which acts like your slicer on the way to its resting place. It's the securing part which has most of my attention in your suggestion (getting it off might require another cutting episode, like my driveshaft!), but also that I'd need something about 30" long to go over the repair area as well as have something to beat on to get it to that point. Once on, particularly if I had to heat it to get it off, I'd be afraid of compromising the epoxy if I had to notably heat it to expand enough to make a difference (though aluminum should expand markedly faster than SS, I'd think). Hammering to try to get it to go UP - against a chamfered end - would be pretty interesting, too :{/) If I could manage a small enough portion - looking at my pix, with the ruler showing approximate actual area involved - perhaps by peening I could get the aluminum expanding sufficiently to slide off, but I'd sure hate to have that sort of abuse wind up causing shattering of all that work I'd just done. (I'm trying to not only fill the pits, but end up replacing that 2-8 thousandths of an inch of missing material, recall. I suspect that whacking on it might cause some flaking of that very thin stuff - and I'd be left with sharp 1-4 thousandth inch [half the 2-8 missing now] edges of the stuff remaining...) In working with West System, and the AdTech fairing compound I used on the hull, I've very successfully sanded it "green" - that is, partly but not fully cured - no tack, but able to make an impression with a tool. Does this stuff act the same way? My contact at Devcon made it sound like I couldn't touch it until the outside was hard, but then, it would already be as hard as it would get, just not all the way to the bottom. Of course, I'd expect to take it down in stages, like I did the polishing on the anchor roller system repair I did, but I was using power tools, and dimensions weren't critical as I'm trying to make them here, and that was a great deal of work. So, I'm stuck with hand tools, and, as you've identified, don't want to be faced with taking down hundredths of an inch of steel equivalent. Thanks for the heads-up. I'll try some test spots on some of the scaffolding around the boat and see how they respond to my attempts and timing. Other comments and ideas solicited :{)) L8R Skip -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog When a man comes to like a sea life, he is not fit to live on land. - Dr. Samuel Johnson |
#4
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Tue, 24 Apr 2012 19:26:24 -0400, WaIIy wrote:
On Tue, 24 Apr 2012 11:55:25 -0400, "Flying Pig" wrote: So, back to all my begs in one ask-it, are there any better ideas? And, if this idea is da bomb, what's the best way to manipulate this sanding shoe to achieve the best results, in your collective opinion? L8R, y'all Skip, working on the boat Are you SURE you trust this epoxy? What's going to happen when the stainless corrodes and starts popping the epoxy off? It's not too late to stand back and rethink this thing. I haven't paid much attention to this, but dressing a pitted shaft is something I'd avoid if the cost for a new shaft isn't outrageous. And if I did dress it, a pro would do it. They have flame metal spray, welding build-up, etc for shaft restoring, By the time you figure the material/labor/doubt cost of DIY, it might be better to buy a new shaft or have a pro rebuild the old one with proven techniques. -- Vic |
#5
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Tue, 24 Apr 2012 11:55:25 -0400, "Flying Pig"
wrote: If you've been paying attention, you know I've dropped my rudder and have been removing prior attempts to epoxy pits in the shaft - done in a convoluted, upside-down manner, inside the boat - which turned out badly. With the rudder out, I have access to it conveniently, to do it up right (well, as best as possible in that it can't be sent off for grinding, rewelding, and machining to round again). I believe I have all the prior epoxy out. Some of the pits have tunnels up or down, too, which, as I worked them out with the pick, displayed remnants of prior packing material. Not so good. The good news is that nearly everywhere I managed to pick off shows very bright under the old epoxy, so it's clean (or will be when I use a brush and acetone to remove all solubles which may be hiding on the surface, and which would impede bonding). The area covered by the packing gland has minimal reduction in diameter - mostly 2-5, and at worst, ~8 thousandths of an inch (out of 2"). However, I'd like not to have even that, if I can avoid it... Ed. Note: I started this last night, but abandoned it for a while so I could run up to Vero to take my wife out for dinner on our 9th anniversary. In the meantime, I THINK I've answered my own question, below, which I'll show at the bottom, but in case there's a better answer, leave this he Which leads me to ask about how to - in this group's collective wisdom - best sand the Devcon Plastic Steel Epoxy I'll put on, using the top and bottom of (up and down from) the newly epoxied area (Plastic Steel is touted as machinable, drill-and-tappable and otherwise as hard as steel when it's fully set) as a guide, to build that back out, but still maintain roundness. Any variance wouldn't do the packing any good, I don't think, regardless of whether it's smooth. Sanding the epoxy when it's green should allow me to have minimal, if any measurable, impact (from sanding away good metal) on the unpitted sections of the shaft, I believe. Even if that weren't true, it is of no consequence in that those areas do nothing related to water intrusion, and that amount isn't relevant to strength. Firstly, regardless of what "they say" devcon is not as hard as steel. True it is machinable, tapable, etc., but then so is nearly any other solid material - you could cut threads in a pound of butter, if you keep it cold enough. As for sanding green epoxy, essentially what you are doing, it has never seemed very effective to me. the yet to fully harden epoxy balls up, clogs the sand paper, and generally results in me stopping the job and waiting until tomorrow. I think you will find that waiting until it fully hardens will result in an easier job. What I would suggest is to make up some flat "sandpaper boards" by gluing strips of, say 80 grit, sandpaper to a wooden backer to make a hard, stiff, "sandpaper file" device. I'd also make some in 180 grit. Then sand away, across the shaft, with the 80 grit and when you start touching the shaft then switch to the finer grit and finally finish up by sanding "around the shaft" and finally, using strips of sand paper/emery cloth, by sanding across the shaft like shinning a shoe. This should give you no problems with sanding away appreciable amounts of shaft and should result in a reasonably round surface.... remember that the packing in a stuffing box is not a hard material but in fact a rather flexible material and will seal quite happily on a shaft that is not absolutely, perfectly, round. Fortunately, after I re-install the rudder and shoe, I have complete access to the rudder tube/packing gland before I reassemble the steering gear (which, of course, will require the packing nut be slid on before that). I'll use feeler guages to exactly (well, as exactly as I can) center the tube in the shaft, using a jack stand to support the weight of the rudder itself, hanging off the shaft (which would put pressure on the aft portion of the shaft), but without raising it from the shoe. That will allow me to use the very substantial steering setup (see "drop it" in the "third try" section of the rudder gallery for the disassembly of that), with its two heavy delrin bushings, to keep it centered. My steering is Scotch Yoke, which is two arms (push-pull), so I won't have any leverage to the side when applying turning forces. So, my repair should be under the least possible stress on the packing gland when it's finished - or, at least, that's my story, and I'm sticking to it :{)) So, I have my repair sequence thought out. Any ideas about how to manage sanding of the epoxy excess from a perfect 2" round outcome? Pix to this point start at http://justpickone.org/skip/gallery/...+Old+Epoxy+Out Ed. Note: So, that's what I'd had last night. In the meantime, I came up with various sorts of pipe solutions - 2" PVC, a 2" nipple, and, today, as I was wandering in the yard and happened upon the welder here, I realized that he probably used 2" aluminum pipe in his work. He confirmed that he did, and that 2" dimension was ID, and has offered me a cutoff. I don't think that I can get it down the shaft, and if I could, there wouldn't be room for sandpaper's thickness, even if I could figure out how to adhere it. I'd first test it to see how exact it was, of course; if it's very slightly oversized, that changes matters, as, of course, its being slightly undersized would, in my thinking. However, I believe that if I cut it lengthwise at slightly less than exactly half, I will have a small section which I can carefully ram/wooden-hammer (lengthwise) over the shaft, thus expanding it slightly so as to allow for sandpaper's thickness. This would solve both the straight line challenge I posed above, as well as enhance the ability to end up with a round finished product, by going not only up and down the shaft, but around it with this slightly-more-than-half pipe. If I can't make it expand enough, I could use the slightly-less-than-half-pipe nearly as well to the purpose. Both would be amply stout to preserve a straight line, my original thought/challenge, from good material over pit repair to good material on the other side, but would have the advantage of a curvature closely matching that of the shaft. So, back to all my begs in one ask-it, are there any better ideas? And, if this idea is da bomb, what's the best way to manipulate this sanding shoe to achieve the best results, in your collective opinion? L8R, y'all Skip, working on the boat -- Cheers, Bruce |
#6
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Tue, 24 Apr 2012 11:55:25 -0400, "Flying Pig"
wrote: If you've been paying attention, you know I've dropped my rudder and have been removing prior attempts to epoxy pits in the shaft - done in a convoluted, upside-down manner, inside the boat - which turned out badly. With the rudder out, I have access to it conveniently, to do it up right (well, as best as possible in that it can't be sent off for grinding, rewelding, and machining to round again). I believe I have all the prior epoxy out. Some of the pits have tunnels up or down, too, which, as I worked them out with the pick, displayed remnants of prior packing material. Not so good. The good news is that nearly everywhere I managed to pick off shows very bright under the old epoxy, so it's clean (or will be when I use a brush and acetone to remove all solubles which may be hiding on the surface, and which would impede bonding). The area covered by the packing gland has minimal reduction in diameter - mostly 2-5, and at worst, ~8 thousandths of an inch (out of 2"). However, I'd like not to have even that, if I can avoid it... === Well everyone else has had a shot at this so I'll dip my oar in the water also. Rick is on the right track with his mold approach but I'd do it differently. I'd buy a sheet of heavy duty mylar which is available at any art supply store or sailmaker. Next I'd coat one side of the mylar with wax or mold release. After filling the pits with Devcon/epoxy/Colloidal Silica or whatever, I'd wrap the shaft tightly with the mylar (wax side down of course) and try to squeeze out any excess epoxy as I wrapped. Leave the mylar on until cured by wrapping it with masking tape or some such. If done properly, this will minimize the high spots and the amount of sanding to be done. The sanding should be done with long strips of emery cloth or wet and dry sandpaper, using them like a shoe shine cloth wrapped around the shaft at about 180 degrees. Change the angle frequently to avoid making an oval shape. I have successfully dressed the shafts on anchor windlasses in this way after they've become dinged/distorted. |
#7
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Tue, 24 Apr 2012 21:28:47 -0400, Wayne.B
wrote: Well everyone else has had a shot at this so I'll dip my oar in the water also. Rick is on the right track with his mold approach but I'd do it differently. I'd buy a sheet of heavy duty mylar which is available at any art supply store or sailmaker. Next I'd coat one side of the mylar with wax or mold release. After filling the pits with Devcon/epoxy/Colloidal Silica or whatever, I'd wrap the shaft tightly with the mylar (wax side down of course) and try to squeeze out any excess epoxy as I wrapped. Leave the mylar on until cured by wrapping it with masking tape or some such. If done properly, this will minimize the high spots and the amount of sanding to be done. The sanding should be done with long strips of emery cloth or wet and dry sandpaper, using them like a shoe shine cloth wrapped around the shaft at about 180 degrees. Change the angle frequently to avoid making an oval shape. I have successfully dressed the shafts on anchor windlasses in this way after they've become dinged/distorted. Good thinking, Wayne. May I add a "mod" or two? Your post triggered a memory. Saran wrap makes a great "mold release", actually better than mold wax. It could be wrapped around the shaft first. Heavy duty mylar sounds good, as well as thin metal, aluminum or maybe better stainless. Pre-formed by working around the shaft before the epoxy. How about however many engine piston ring compressors needed to "wrap" the mylar/metal sheeting? You know, those things that squeeze the rings down on a piston so you can slide it into the cylinder? This method will leave a slight ridge where the mylar/metal overlap, but should be a problem. I agree 100% with the "shoe shine cloth" method of finishing. Rick |
#8
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Wed, 25 Apr 2012 06:23:53 -0500, Rick Morel
wrote: Your post triggered a memory. Saran wrap makes a great "mold release", actually better than mold wax. It could be wrapped around the shaft first. === I have used saran wrap and also light weight plastic sheeting. They both "release" well but tend to leave wrinkles in the finish. Heavy mylar sheet like pattern making material will not. |
#9
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
On Wed, 25 Apr 2012 07:55:17 -0400, Wayne.B
wrote: On Wed, 25 Apr 2012 06:23:53 -0500, Rick Morel wrote: Your post triggered a memory. Saran wrap makes a great "mold release", actually better than mold wax. It could be wrapped around the shaft first. === I have used saran wrap and also light weight plastic sheeting. They both "release" well but tend to leave wrinkles in the finish. Heavy mylar sheet like pattern making material will not. Good point! Rick |
#10
posted to rec.boats.cruising
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Round and round we go, or, "sand in your eyes"
Hi, all,
Thanks for all the discussion so far. I'll try to address each of the issues/suggestions I've seen: Flaking/breaking off from future corrosion: I don't know. I suspect (but, obviously, can't prove) that there might have been a bonding issue causing the pits. The shaft has pits only in the area of the packing contact (and slightly above), none below. My pix show a ring at the bottom (and one fissure which extends downward, but that's the ONLY exception on the downside) of where the bronze tube tops out. Everything else is above that point, and ends slightly above where the gland tops out. Having moving water below the gland would help with no corrosion/pits there, but having the extent above the packing gland suggests there is something more than just unoxegenated water at work here. As this pitting was present to at least some degree when we bought the boat, I have no idea how long it took to get to that stage, and what, if any, progress occurred since we have had it. We've next to never been tied up for any extended period of time (a couple of months during our 2009 refit, in a marina with recently new power stands being the exception), but the boat spent most of the 15 years before we bought her at a dock in FTL. There may have been some issue with the electricals there; certainly, the zincs on the shaft and prop were much more worn than I'd have expected after a short while between their haulout and spiff-up and our haulout for our initial refit. There was a bonding strap to the shaft which I had to remove to get the steering gears off; I'm going to leave that off, as it goes to the ground plane stuff, and we've got plenty of other help in that regard. The ground plane stuff is electrically grounded, but the thru-hulls aren't part of that, other than our keel cooler, so there's no issue there. If there WERE some internal electrical issue, this should remove that. Back to the question/concern of future pitting/corrosion displacing the epoxy, if, indeed, there is any connection (pardon the expression) I'd hope that this will remedy that. I have some difficulty believing that the level of pitting - and the very localized nature of it - could be just salt water and air exposure. In any event, it took many years to get this point. My conversation with Devcon assures me that my cleanup I've done and will do is adequate for bonding. From Rick's frequent use, and their assurance, and the local machine shop which uses it to do the same thing I wish I could do for this rudder shaft with drive shafts (much higher velocity, of course), yes, I think I trust this epoxy. As to standing back and rethinking, that's what I'm doing by not proceeding yet :{)) Replacing the shaft or having it addressed in a shop: It's impossible to (merely) replace the shaft, as there are massive plates welded to it internal to the rudder. You'd have to destroy and rebuild the rudder to replace it (I'm not comfortable with the thought of cutting it off and welding another to it, for a variety of reasons.) I called Foss Foam, who provided the mold to Morgan at the time of build; he was pretty sure he had it, and the replacement was $2200. As it was new, that was what I'd planned to do, given that I'd thought a new rudder was much higher. However, he searched through all his molds and it was one of the many molds which Catalina dumped when they bought Morgan, in either the bay or the Gulf, which wasn't recovered. To make a new rudder he'd have to have mine, and fabricate a mold from it, and an extra $1500, which was my cost; he'd keep the mold. Between getting it to him (and the new one back here) and the now-cost of $3700, I abandoned that thought. I've queried all the usual suspects about the norm of my experience in shaft repair, which is to turn or grind down to all clear, building up metal to an excess, and removal by turning (e.g. a crankshaft). There is no place I've asked, including asking for referrals to someone else, anywhere, with the means to accurately remove new metal if this were to be done. Without the means to do that, I'm stuck with what I have, and/or can do here, or a new rudder. See above about the new rudder :{/) Sanding green and/or flat: I'm familiar with the pilling and clogging of the sandpaper. Sandpaper's (relatively) cheap :{)) However, getting down to the base metal of the area of the pits, if I weren't to try to build it back out to the original dimension, is something I'm not worried about. If I'm not going to try to build it up or be concerned about roundness, I can easily attack it either with a machine or with the sticky-back stuff we used on the fairing compound, including some finer grits I also ordered, in 2.75" width rolls. Leaving the plastic on the sticky side allows me to make a shoeshine cloth (it's what we did the back of the rudder with, e.g., when it got another layer of cloth, and fairing compound, but was still in the skeg slot) style sanding setup without having it stick to my hands :{)) I'd, of course, go through several grits before stopping. In my work on other entirely rough (mill finish) SS, I worked my way up from 80 and stopped at 600, then used two grades of rouge on a buffing wheel in my 4" grinder. Of course, sanding was with a power sander, and still a lot of work. If I started with something relatively soft (the assertion that this stuff isn't as hard as steel is agreed), I think I could make it happen without croaking from the effort. So, I'm not afraid of the work, other than I'd like to make it as little as possible. However, I'd rather it were as round as possible, and also as back-to-2" as possible, which is why I went to all the thought about a mold (slightly expanded 2" aluminum pipe, at this point) for the sandpaper. The only reason we're doing this is to end, once and for all, the stream of water which has been running through our bilge; that stream is what caused all the rust in the driveshaft bearing due to the vapors created. As it is, I'm having to replace several clamps due to accelerated corrosion in the same areas. If it's smooth and round I should be able to get it to as few drips as would evaporate before it got more than a couple of feet along. Attacking it as Bruce has suggested, with a hard flat "something", across the shaft would, at best, yield the same configuration (as to round) as before, because I'd be stopping the removal at the point of exposed original (slightly undersized due to 30+ years of wear, and especially tight glands attempting to stanch the flow for the last 5 years and perhaps before by the prior owner) metal, but if I weren't pretty aggressive in the shoeshine phase of it, leave lots of flats/edges. If that (the above/Bruce's suggestion) is sufficient, it certainly would be simpler as I could be more aggressive without concern for perfection. Has anyone had experience in out-of-round shafts to say whether the standard packing will do its job? If I were to do a lot of shoeshining, I think I could attack the flats/ridges, but probably not get it perfectly round no matter how I danced around the circumference to avoid irregularity... Smoothing before sanding: I have coke cans, saran wrap and other possibilities for minimizing irregularities in the surface, but no Mylar pattern making material. Certainly, using something of that sort would minimize excess needing sanding. However, if tightly compressed, it might also make it such that the original configuration (however much wear-removal was present) would likely result. Then, there's the earlier suggestion about tapping a 2", mold-released pipe down. Getting that off is a previously expressed concern :{)) What kinds of places would use Mylar patternmaking material where I might obtain some scrap (I only need ~4" square)? I really had only thought to build it out to the original 2" as a side benefit of my pipe-sander's rigidity/conformance-to-shape. If the experience with slightly undersized shafts (anyone??) shows that it's of no consequence to a standard packing gland (my thinking is that it shouldn't, particularly when the packing is 5/16" - 0.3125 but both sides, 0.625 down to max reduction to 0.617, a 1.3% difference at worst), I'll abandon the build-out-to-original part of my thinking. So, who's got a measurably undersized shaft which works just fine in a standard packing gland? Thanks for all the ideas and troubleshooting! L8R Skip -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog When a man comes to like a sea life, he is not fit to live on land. - Dr. Samuel Johnson |
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