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Old 29-01-2009, 11:31   #16
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Bene...Cheech answered your question to me better than I could. I agree entirely.
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Old 29-01-2009, 13:44   #17
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Wow..
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Old 29-01-2009, 15:26   #18
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Is your model boat prone to rudder failure? One cup of water in a rudder the size of yours is not very much. If you have lots of time and talent or money then by all means take it down to the web and reweld. You are lucky that you can contact the original builder and talk about where the rudder welds are located then do a little exploratory surgery with a hole saw to find where the web is welded to the stock and investigate the integrety if you have little confidence in the rudder.
Good luck. This is a hard one to choose.
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Old 29-01-2009, 15:39   #19
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Good grief......................obviously, you have the boat in the yard (otherwise it"s pretty hard to get water out of the rudder).

I would advise you to talk to the yard manager and see what he thinks about getting a cup of water out of the rudder.

Fiberglass does not bond well to S/S. Your rudder is basically hollow (except for some foam). As you sail, the rudder may go up and down in the water as much as 2-3 feet. This changes the forces on the surface of the rudder tremendously. One instant, the surface may have 20PSI on the surface trying to squeeze air out. The next moment, it may have 10PSI on the surface. These differences in pressure are going to create a vacuum inside the ruder unless your rudder is totally solid core and/or perfectly sealed (IMO not probable).

To think that you can keep water out of a foam core rudder is a bit naive IMHO.
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Old 29-01-2009, 17:05   #20
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You are correct about the naivete' I would say. That's why I indicated probably 50% or more of the boat out there probably have water filled rudders. My solution suggests filling the rudder with lite Epoxy "foam"...basically a solid rudder. But another point is maybe we are going too far! If the boat is basically a weekender, occassional use and that new, i wouldnt worry about it. If it is going to be your home, sail you over the horizon and you want it right, it's really not that hard a fix. The welds may be fine at this point if the boat is fairly new. Just dry them out good, put the shell back on and fill 'er up! I'm not sure I would personally rely on the yard guy to make the decision though. you can hole saw the rudder to try to look at the welds, but by the time you are done goofing with that, and if you need to get rid of the water saturated foam core, removing a side panel goes pretty well.
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Old 10-02-2009, 17:20   #21
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Cheech - when you suggest epoxy "foam", what exactly are you recommending? Is it some product that you mix with epoxy resin, the way you would mix microballoons, etc. Or, is it a product you purchase ready to go, and do not mix with epoxy resin.

I have my rudder apart, and am considering alternatives to fill the void cavity with.

Thanks in advance!
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Old 10-02-2009, 18:03   #22
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I used a product called "ruddercast", It was a mil spec product that was actually used to cast the rudder with no fibregalss shell on small gunboats. I got it as surplus. I searched when this came up and didnt find it on the web. Personally I would probably use whatever Epoxy resin I could find that was good on the budget. It will likely take 4-5 gallons...? It's just filler really. So inexpensive epoxy resin with non water absorbing filler. Maybe micro ballons? not sure which are non absorbing. How did the welds and metal work look?
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Old 10-02-2009, 18:43   #23
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Quote:
It will likely take 4-5 gallons...?
Wow, that will make for one heavy rudder.
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Old 10-02-2009, 22:58   #24
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I don't have any experience with this but you can usually rent metal detectors at a surveyor's equipment rental place. I also don't know that a metal detector would work on Non ferrous metal. by using a detector you could possibly map out the steel portion of your rudder. From there you could drill a few 2" holes with a hole saw starting at the bottom. If it is dry at the bottom then I wouldn't worry about going up any further. If it is not you might be in for the full rudder job as mentioned above.
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Old 11-02-2009, 06:05   #25
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Cheech- my metal framework was fine, but i will weld gussets in between the rudder post and existing framework, now that I have opened it up.

see link for pics:
Possible Rudder Rebuild Questions

Bene - didn't mean to steal the thread, but it is related. My rudder is 30 years old, so I opened it up to check inside. Mine metal framework had been covered with a mixture of epoxy resin / glass fibers, so it ended up being much harder than just cutting the outside skin off, to have a look. After cutting deep enough that the skin "should" have came off, it would not budge, so I had to cut deeper, deeper, etc.

Your's may cut much easier, but I would try to check with a bene owner, or the company, to see how it is made / how easy it would be to open it up.

Now that mine is open, I will beef it up a bit, b4 filling and covering over.

Since yours is only 7 years old, I personally would not open it up, unless you are going far offshore, as I do believe some water intrusion is common.
I will likely add a ring of 5200 at the top, where the rudder post enters the rudder, as this may prevent further water intrusion.
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Old 11-02-2009, 09:40   #26
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"Wow, that will make for one heavy rudder." I think if he using some kind of lightweight filler, the actual weight "in the water" wont be too bad. I suppose you could make a closed cell foam "core" before closing it up and encapulate that with the resin.
Northeaster: I wonder if it really has to be epoxy....? is there another less expensive non water absorbing option? Just a thought. Also, ask about heat while it is curing, mine was a special product made for the purpose. Maybe mix and and put it in at a gallon or less at a time, talk with a supplier, I know they make "casting resin". Anyone else here got a suggestion for a product?
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Old 11-02-2009, 10:09   #27
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I think you hit on it with the foam covered with epoxy/cloth. Casting epoxy is not very strong. Epoxy itself is not very strong, its brittle. What makes it strong is the fiber that is used with it. Epoxy cloth is more flexible than most other resin/cloth. I'm not sure what foam but it should be closed cell and fairly dense.

Epoxy resin weighs about the same cured as it does in the can. So 4 - 5 gals. along with the weight of the hardener is pretty heavy.

I'm not sure if I posted this before but here is a link to some information on rebuilding a rudder (actually building a rudder). I don't think that this case calls for a complete rebuild but hopefully it will give you some ideas.

WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Rebuilding a rudder
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Old 11-02-2009, 10:29   #28
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The question is density. I imagine the epoxy foam will be less dense than water so would have positive bouyancy in water. Although maybe weigh 40-45 out of water.
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Old 11-02-2009, 10:38   #29
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I agree that epoxy - without cloth/mat ,etc -is weaker.

However, my main reasoning for filling the void with epoxy and some type of epoxy and filler is to prevent any possible future water intrusion from damaging the welded framework, as it would be encased in epoxy.

I think that filling the cavity with foam, although widley practised, can lead to wet foam causing corrosion of the framework. Why focus on the weakenness on epoxy resin (without cloth) when it is not being used for strength, but instead as a replacement for "weak" foam.

Just trying to find the best product to fill the void with, that keeps water away from the framework, and adds strength if possible.

Of course, encasing the framework with resin makes future work harder, but as my rudder framework was is great shape, after 30 years use, I think it kept the water out!!

I may consider encasing the framework with epoxy /coth, and then thickened epoxy, to keep the water out, then filling the rest with foam.

re: heat, I would consider pouring resin in in small batches, waiting till one kicks, before pouring in the next. As long as this was done before the previous was fully cured, they should still make a chemical bond.
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Old 11-02-2009, 10:45   #30
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here's a couple pics of mine opened up - notice the encasing resin, that was much harder to get through than simply cutting through the outside skin!!
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