WAHOOOOO!!!!
Thanks to all for the input... i have learned alot about aluminum, paint, anodizing, wasting gas, not doing a shred of work in a day, and in the end...... i am where i started... naked metal!
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From my experience as ground crew in the last
open
Worrell (hmm- there was a
yellow boat
in that one!!) the only Mystere in that race ended up fracturing every rudder casting on the East Coast they could get there hands on!! Clearly a design flaw! I would
retrofit/upgrade
to some proven rudderheads/systems ala the old NACRA design or some of the Hobie designs IMO- parts if needed will then be plentiful/easy/cheap to come by and they will be anodized from those companies-
Kirt
That's a great way to go...but it will be a fair bit of work...the Mystere has quite a lot of freeboard at the transom so the non=-OEM heads will need a lot of modification to extend the tops...gotta get the tillers over the aft deck while still leaving the right amount of blade in the drink.
Mike.
I do sail with a Mystere 6.0 that has Nacra 6.0 rudders on his cat. He loves them... i considered that but i didn't see anytone parting out a smashed nacra 6.0.
When i stated this .. my goal was to purchase 1 back up casting after finding a hair line crack in a casting. I tried to get it welded (repaired) but they guy did a horrible job.
Always avoid welding Alu alloy. You will destroy the heat tempering in t he area of the weld...making the strength drop to about 50% of what it was.
how else do you repair a cracked casting if not getting it welded?
Shame on you for not asking me. I can get them powder coated for lunch at Shells. Also someone posted a do-it yourself anodizing link here a while back. I don't have it here at work. Search this site.
Call me and you can have them done tomorrow.
Shame, shame, shame on me!!!
Lunch including drinks???? that could cost more than the castings! lol - kidding!
Thank you for the very nice offer Mike.
I talked to a powdercoater (afer leaving the anodizer) and he said since the tubes were anodized, they would have to
off gas them
and that might make them bubble... he also said it would cost me $120! YIKES...
Our friend has taken them to work and is gonna paint them (the right way) and i will be done with it...
If they last a few years i will be happy. I still have the blue ones so i have spares.
Such is life. Live and learn... damn you Ecole de Voile Sanoucy.
OOp. Wouter says
Alu oxide is conducting
.
Nope. Wrong.
I worked for Anaconda Wire and Cable Co in their research lab making and testing anodized coatings for their good insulating properties.
Now--If you bust thru this thin tough coating, there is raw metal that corrodes yada, yada...
> hence galvaic corrosion will progress much like it would with a non-anodised element.
I stand corrected.
I should have said that the oxide layer is often so thin that for most electrical applications an alu element with alu-oxide on the outside (anodised) can be considered to be a well conducting element. Hence the need to avoid touching any powercables and the reason why 2/3rd of all wiring in the world is made of aluminium threads. These wires conduct very well, are very bendy, are lightweight and are very cheap when compared to copper.
Of course bare aluminium will form its own alu-oxide layer on the outside in mere seconds to minutes. It is practically impossible to have pure (non-oxidized) aluminium outside of the lab (shielded from oxigen).
Wouter
thanks for clearing up that ... i wasnt sure if i could sail until i got that straight... <img src=
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How about adding a thick shell of fiberglass and epoxy over the outside of your cracked casting. Pretty Cheap DIY. After rounding the sharp shoulders on the INSIDE of the rudder space, run the fiberglass around these curves with masking tape. This will hold the shell on. Add ss machine screws?
I have a H16 rudder casting cracked from the rudder bolt hole ($150 new- ouch): I bet it will last for 10 years in use.
well... as the song goes... if i knew then, what i know now!
After finding the small crack, I brought them to a guy to do a spot weld on... he ended up breaking off the end (where the bolt goes through the rudder, even though it was not near the crack) and then welding on a heavy block of alum (to hide his damage).
This doubled the weight, effected the helm, and he didn’t get the bolt hole back on straight (which caused me to have an offset rudder). My friend is a welder and saw the crappy job the other guy did. He asked me to bring the casting over so he could clean up the sharp edges and make it look a bit better. He is the one who noticed the bolt hole had been broke off after seeing internal welds….
I have learned a lot about treating alum… how to repair, and what not to do in the future. Another lesson was, Don’t assume replacement parts will be anodized, just because the originals were… make sure by asking and not leaving any details out when ordering over the phone. Hopefully others will learn from my lessons…
Thanks to all that provided info, even the details on alu-magn, galvanic corrosion and conductivity!