Cavitation plate crack

NHGuy

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Joined
May 21, 2009
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3,631
I know anti ventilation plate...don't hate.
But on my Gen 2 Alpha 1 I have found a pretty big crack. It's on the upper plate on the port side and extends about 5" forward from the bolt that joins the halves. As it goes forward it curves out til it gets to the edge. And to make matters worse it's offset about 1/4 inch. Meaning the cracked part is 1/4" higher than the main part of the fin.
Here's my question. Would you stop me warming up the plate with a plumbers propane torch just enough to straighten the plate? Then I'll JB it or take it to a guy that does TIG welding in the next town. I don't see any reason not to, but since I haven't seen anyone else with this problem I thought I'd put it out there in case I am missing something.
 
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Bondo

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Apr 17, 2002
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70,990
Then I'll JB it or take it to a guy that does TIG welding in the next town. I don't see any reason not to,

Ayuh,.... Ya might better just bring it to the welder guy,....

Aluminum, hot or cold will just snap off at the crack,....

Ya might better warm it til it's to hot to touch, 'n let it cool, then try straightenin' it,...
By annealin' it, it might bend back, without snappin' off,...

Aluminum don't show heat like other metals,...
It's Hot,... then it melts into a puddle,....
Nothin' in-between,...
 

fhhuber

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Jun 19, 2014
Messages
1,365
Pull it off and take it to the weld shop. Do not try to straighten it.

it may not be repairable at all.... But if you mess with it incorrectly you'll guarantee its not repairable.

Most likely you need to replace the part.
 

NHGuy

Captain
Joined
May 21, 2009
Messages
3,631
Yeah, I just looked again in the light. It's a 2.5" crack with a 1/8" offset. I can straighten it with my bare hands (and they aren't as strong as years ago). I'm going to hold it in place with a clamp and have it TIG'd.
Did some reading on annealing, it would soften the metal but how to re harden it? There's not a good way that I can think of.
 
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