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

"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 !
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- Dr. Samuel Johnson

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

On Wed, 25 Apr 2012 11:34:02 -0400, "Flying Pig"
wrote:

What kinds of places would use Mylar patternmaking material where I might
obtain some scrap (I only need ~4" square)?

===

Sailmakers will definitely have some, possibly canvas shops. You can
usually buy individual sheets at art supply stores. It's also
possible that you could use a small piece of Strataglass or something
similar. Canvas shops will definitely have that.

"Wayne.B" wrote in message
...
On Wed, 25 Apr 2012 11:34:02 -0400, "Flying Pig"
wrote:

What kinds of places would use Mylar patternmaking material where I might
obtain some scrap (I only need ~4" square)?

===

Sailmakers will definitely have some, possibly canvas shops. You can
usually buy individual sheets at art supply stores. It's also
possible that you could use a small piece of Strataglass or something
similar. Canvas shops will definitely have that.


Hi, Wayne, and thanks for that.

Strataglass I can come by, and it's possible that my canvas shop has some
mylar, if that's common - but I'd inferred from what you'd said that it
would be harder/stiffer than that. From our windows, it seems to me that it
would not make a very straight (straighter than saran wrap, of course!)
surface, as flexible as it is, and what I see canvas folks using for
patternmaking is VERY floppy, not very heavy stuff..

Inferred is that the stuff you're talking about is pretty flexible?

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

On Wed, 25 Apr 2012 13:55:48 -0400, "Flying Pig"
wrote:

Strataglass I can come by, and it's possible that my canvas shop has some
mylar, if that's common - but I'd inferred from what you'd said that it
would be harder/stiffer than that. From our windows, it seems to me that it
would not make a very straight (straighter than saran wrap, of course!)
surface, as flexible as it is, and what I see canvas folks using for
patternmaking is VERY floppy, not very heavy stuff..

Inferred is that the stuff you're talking about is pretty flexible?

===

Mylar comes in different thicknesses. The kind I'm thinking of is
probably comparable to crispy new (and relatively heavy) Strataglass.
It needs to be heavy enough that it is relatively self fairing as you
wrap it around the shaft. You can wrap multiple layers of course for
extra body.

On Wed, 25 Apr 2012 23:01:32 -0400, Wayne.B
wrote:

Mylar comes in different thicknesses. The kind I'm thinking of is
probably comparable to crispy new (and relatively heavy) Strataglass.
It needs to be heavy enough that it is relatively self fairing as you
wrap it around the shaft. You can wrap multiple layers of course for
extra body.

Thinking about it, thick is not good unless it's cut to perfectly butt
the edges, which would be difficult. Otherwise, the epoxy will make a
shaft increasing in diameter to a raised "cliff-face" where the mylar
wraps over itself. The thicker the material, the longer the incline
portion.

Wish I could draw a picture, but let's say the wrap is 1/4" thick (I
know, that's ridiculous, but..). Wrap it around a shaft and look at
the end. You'll see a curving right triangle with the base 1/4".

Rick

In article , says...

"Wayne.B" wrote in message
...
On Wed, 25 Apr 2012 11:34:02 -0400, "Flying Pig"
wrote:

What kinds of places would use Mylar patternmaking material where I might
obtain some scrap (I only need ~4" square)?

===

Sailmakers will definitely have some, possibly canvas shops. You can
usually buy individual sheets at art supply stores. It's also
possible that you could use a small piece of Strataglass or something
similar. Canvas shops will definitely have that.


Hi, Wayne, and thanks for that.

Strataglass I can come by, and it's possible that my canvas shop has some
mylar, if that's common - but I'd inferred from what you'd said that it
would be harder/stiffer than that. From our windows, it seems to me that it
would not make a very straight (straighter than saran wrap, of course!)
surface, as flexible as it is, and what I see canvas folks using for
patternmaking is VERY floppy, not very heavy stuff..

Inferred is that the stuff you're talking about is pretty flexible?

I would suggest looking for a piece of the material they use for laser
printing transparancies. IIRC, it's mylar or something similar and
reasonably available and pretty cheap.

Mark Borgerson

On Wed, 25 Apr 2012 11:34:02 -0400, "Flying Pig"
wrote in part:

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...

This part I can address. Unfortunately the answer is no, it will not
do the job.

As the high spots go by, they will compress the flax, or move it out
of the way if you will. The flax will not "bounce back" as the low
spots go by, leaving a gap.

Thick of a rubber ball and a ball of packing material. Hit the rubber
ball with a hammer and it compresses, than resumes its original shape
/ Hit the ball of flax with a hammer and you have a disk with rounded
edges. Remember the "trick" of fitting too thick flax by rolling a
pipe on it to flatten?

Rick