Hi guys,
Few days after liftout I noticed water dripping out from the rudder (Bav 33C 2006) from the trailing edge half way up.
Scraped / sanded whole edge and noticed that its cracked.
Opened up dozen holes and few big ones to drain and dry.
Any suggestions on to repair the rudder? What are my options? Do I need to grind whole rudder down to grp then epoxy treatment? How can I reinforce the training edge?
This week I will also lower the rudder but will not fully remove.
Good news is that the bearings are in good condition.
Tnx
SY CRYSTAL
I think your best bet would be to ask Jefa for their recommendations. If the inside has been saturated, there may be corrosion of the internal tangs, or their connection to the stock.
I had the same thing. Drilled holes and let it dry out, filled holes.
Quote from: Nigel on December 08 2015, 15:56
I had the same thing. Drilled holes and let it dry out, filled holes.
I followed the same treatment (B39cr 2005)
Tnx, so basic epoxy filling only. What about the crack on the trailing edge?
I had the same. According to Jefa (http://ftp://ftp.jefa.com/rudder/maintenance/Rudder_blade_anti_fouling_instructions.pdf), the rudder should have a bead of sealant at the top where the stock enters the blade. If it does not (the JP3 bodgers *grumble* never bothered to do this), water gets in there, so this is very common.
I've drained mine, filled the holes (and found evidence that this had been done before) and used a Dremel with a conical burr to cut a groove into the top of the blade all around the post, which I then filled with Sikaflex.
As for damage at the edge, if it's bad I'd grind it off a bit and glass it to reinforce, otherwise just fill and fair it - the edge is not particularly strong and suffers easily. I also slapped on two coats of Interprotect before Coppercoating, but mostly just because I had some left over.
I found this video (https://www.youtube.com/watch?v=HqBXDuI5NzY) helpful in understanding what is inside the rudder, and Jefa also publishes technical drawings on their FTP server (but beware of JP3 not having built rudders to those plans).
Cheers, but slight issue when laying even thin layers of glass around the tight edges. High risk of leaving air pockets which is not ideal.
By the way, what's the easiest way yo plug the holes? Few are 4mm and few 10mm.
Tnx
If you want to lam-up the trailing edge (which wouldn't be a bad idea if it's cracked), you need to:-
1./ Get all the antifoul off, and grind the gelcoat back to the grp mat, say for a couple of inches on each side.
2./ Get some close-weave glass tape or sheet (and cut it into strips). You want something about 200-300 gram
For the lay-up you'll need some polyester resin, and some filler (glass bubbles or microballoons)
3./ Glass 2 or 3 layers onto one side, so that it hangs over the back edge of the blade by about 10mm
4./ Mix some resin with glass bubbles until it becomes like toothpaste (too thick to run). You might need to add some silica to thinken it.
5./ With a wooden spatula (or you thumb) gently put a bead of this down the trailing edge, so you fill the gap that would otherwise be left between the 2 lams.
6./ Glass-up the other side with 2 or 3 layers of mat, making sure that you then push both sides firmly together at the trailing edge into the filler.
When all is set, cut the excess glass off the back with a cutting wheel and sand/grind back to a nice edge.
Then give it a good sandng flat, and give it a coat of flowcoat (geloat topcoat).
Job done.
One thing. Depending on how warm it is and how many people there are doing it, you might be advised to use a slow hardener.
Excellent stuff. Can this be done without removing the rudder? I only can drop it to inspect / repair the top side especially around the post as mentioned by others.
Aso whats the wait time between the layers if temp is around 18C?
Tnx
You can do it with the rudder in (probably easier too)
You want to do all the layers at once so that they all consolidate together and into the filler. That's why you want to use a slow hardener.
It should remain workable for about an hour, and take a day cure.
Much appreciated. I'll finish it off with veneziani epoxy / aquastop as this has worked nicely on my keel.
ATB
Hi, Just to add to Bob's "How to" (IslandAlchemy);
use a cable finder to work out where the tangs and post end in the lay -up. Drill a hole about 25mm dia at the bottom of the post half the depth of the rudder and a couple of similar sized holes above. Use a wet vac with the hose over the bottom hole to suck/dry out any moisture. An hour or so does the trick. Keep an eye on the air flow as wet vacs use some of the air to cool the motor. You can open the gap between the hose end and the rudder to adjust the air flow.
Try to get the water out before the bad weather sets in. You do not want the moisture freezing. Ice is 11% biger than water!
Fill the holes with epoxy, dont be tempted to use car body filler it is Hydroscopic.
Best regards.
Ant