Tig welding 4047 on block

martymil

Major General
Sep 6, 2017
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Down Under
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S65 1m
Yes you can patch it up but the problem with cracks especially in alloy is they don't stop but keep going and its only a
matter of time before failure is imminent, its not going to be pretty. How long is it going to last is how long is a piece of string.
 

wheela

Lieutenant
Jun 4, 2021
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Twin Cities, MN
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2015 e84 X1 35i Msport
Yes you can patch it up but the problem with cracks especially in alloy is they don't stop but keep going and its only a
matter of time before failure is imminent, its not going to be pretty. How long is it going to last is how long is a piece of string.
This is often true, but not always; it depends what caused the crack, and if those conditions are still present. Depending on geometry and loading, sometimes opening up of the crack can sufficiently releave the stress to stop crack propogation. Or sometimes something as simple as encountering an inclusion in the material can be enough to stop crack propogation. There's a critical flaw size for a given loading where by the crack won't grow if stess & crack are low enough. That's the question - will the crack keep growing? How big will it get? Could attempting a patch potentially exacerbate crack growth? It's hard to know the answers.
 

SlowE93

Major
Jul 2, 2017
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Just a plane ticket away !
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This is often true, but not always; it depends what caused the crack, and if those conditions are still present. Depending on geometry and loading, sometimes opening up of the crack can sufficiently releave the stress to stop crack propogation. Or sometimes something as simple as encountering an inclusion in the material can be enough to stop crack propogation. There's a critical flaw size for a given loading where by the crack won't grow if stess & crack are low enough. That's the question - will the crack keep growing? How big will it get? Could attempting a patch potentially exacerbate crack growth? It's hard to know the answers.
Copied and pasted from some site off google 🤣
 

shushikiary

Sergeant
Jun 4, 2018
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335xi
I was going to say... I did a google cross reference search to see if that was even true... and it's not. You can easily find it if it was a google copy. It's not even from a text book if you do those searches either, so it was not plagiarized at all.
 

RuskiRacer

Captain
Jul 17, 2019
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2009 e93 335i
Update on the block. It cracked through the oil drainback and into the cooling jacket. Oil started mixing with coolant. Pulled the motor got the guy a new block and swapped all his forged internals over into a new block. Will use the cracked block as a mock up block for turbo kits I will be making. After I light it up with my ar 15
 
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SlowE93

Major
Jul 2, 2017
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Just a plane ticket away !
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E93
Update on the block. It cracked through the oil drainback and into the cooling jacket. Oil started mixing with coolant. Pulled the motor got the guy a new block and swapped all his forged internals over into a new block. Will use the cracked block as a mock up block for turbo kits I will be making. After I light it up with my ar 15
I was just about to clean mine 🙂