Meg Aluminium can "decaying"?

Outlaw · 17th October 2007, 06:54

Hello guys,

while i was trying to set up my shadow mounts on my can, (black in colour) after i removed the tiger gear i had, i realised that there is some sort of "decay" of the metal at places?

i dont know how to describe it, but i think i will set up my micro lens cam to take some pictures and post it here?

its as if the aluminiun has the effect the flowers get when they get bacteria on...(dont know how informative this term is for you, but i am shocked.)

did any of you notice anything weird happening with the can? is there a chance of the aluminium can to disintegrate with time?

Thanks

Spyros

***EBT*** · 17th October 2007, 08:24

its because you're attaching a different metal to the aluminum. Solutions are either to buffer the connection (put some rubber under it) or find a way to attach an anode to it (probably not practical).

Ben Field · 17th October 2007, 08:51

Aluminium is a pretty nasty metal to put in seawater

Galvanic corrosion - Wikipedia, the free encyclopedia

Outlaw · 17th October 2007, 09:33

Quote: (Originally Posted by Ben Field)

Aluminium is a pretty nasty metal to put in seawater

Galvanic corrosion - Wikipedia, the free encyclopedia

Thanks for the link.

Quote: (Originally Posted by EBT)

its because you're attaching a different metal to the aluminum. Solutions are either to buffer the connection (put some rubber under it) or find a way to attach an anode to it (probably not practical).

so it does happen? how do you get to fight this? isn't this worrying? do you have fotos for your precaution measures?

Thanks.

UKSteve · 17th October 2007, 10:04

My solution .. use a plastic scrubber housing :

OK..I know I shouldn't... but couldn't help it!!

Seriously, hope you are taking the same precautions with your Aluminium cylinders and not simply putting steel bands around them. You need to put a rubber layer between the two different metals otherwise the type of corrosion you have found is a great way to knacker the cylinder in a very short period of time. Please tell me you were aware of that already!!!
Steve

***Beanie*** · 17th October 2007, 10:21

Quote: (Originally Posted by UKSteve)

My solution .. use a plastic scrubber housing :

OK..I know I shouldn't... but couldn't help it!!

Seriously, hope you are taking the same precautions with your Aluminium cylinders and not simply putting steel bands around them. You need to put a rubber layer between the two different metals otherwise the type of corrosion you have found is a great way to knacker the cylinder in a very short period of time. Please tell me you were aware of that already!!!
Steve

you mean a bit like this

Outlaw · 17th October 2007, 12:40

Quote: (Originally Posted by UKSteve)

Please tell me you were aware of that already!!!
Steve

Seriously, i wasn't, but i am now!!!

Thanks.

Meng_Tze · 17th October 2007, 12:50

Galvanic corrosion does happen yes, but will it corrode through the material (Al)? In 200 years maybe (or whatever big number, point is; not in our lifetime under normal diving circumstances). It is not pretty on tanks or the meg can, but not a mechanical problem. If you want to make sure it does not happen, put a barrier between the dissimilar metals.

***EBT*** · 17th October 2007, 13:13

Quote: (Originally Posted by Outlaw)

so it does happen? how do you get to fight this? isn't this worrying? do you have fotos for your precaution measures?

Thanks.

You want pictures of my rubber?

Just use a piece of large inner tube.

Ben Field · 17th October 2007, 13:26

Quote: (Originally Posted by Meng_Tze)

Galvanic corrosion does happen yes, but will it corrode through the material (Al)? In 200 years maybe (or whatever big number, point is; not in our lifetime under normal diving circumstances). It is not pretty on tanks or the meg can, but not a mechanical problem. If you want to make sure it does not happen, put a barrier between the dissimilar metals.

How thick is the Meg can?

It ate through some ali goodman handles I made in about 9months. Remember it doesn't need to make a hole just weaken it so it is easily damaged, it also does a good job of sticking thinks together.

17th October 2007, 06:54	#1 (permalink)
Outlaw In search of Law breaking Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Cyprus, Nicosia Posts: 627	Meg Aluminium can "decaying"? Hello guys, while i was trying to set up my shadow mounts on my can, (black in colour) after i removed the tiger gear i had, i realised that there is some sort of "decay" of the metal at places? i dont know how to describe it, but i think i will set up my micro lens cam to take some pictures and post it here? its as if the aluminiun has the effect the flowers get when they get bacteria on...(dont know how informative this term is for you, but i am shocked.) did any of you notice anything weird happening with the can? is there a chance of the aluminium can to disintegrate with time? Thanks Spyros __________________ CMAS - IANTD - TDI Kamikazi Instrustor Trainer DIRRebreather Team Member ---------------------------- "Once an Outlaw, always an Outlaw"
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17th October 2007, 08:24	#2 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,855	Re: Meg Aluminium can "decaying"? its because you're attaching a different metal to the aluminum. Solutions are either to buffer the connection (put some rubber under it) or find a way to attach an anode to it (probably not practical). __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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17th October 2007, 08:51	#3 (permalink)
Ben Field CK+Shearwater Current Rebreather/s: Classic Kiss Other Rebreather/s: Sport Kiss Join Date: Aug 2005 Location: London, England Posts: 1,482	Re: Meg Aluminium can "decaying"? Aluminium is a pretty nasty metal to put in seawater Galvanic corrosion - Wikipedia, the free encyclopedia __________________ www.hugsac.org.uk Beware Fridge Suck
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17th October 2007, 09:33	#4 (permalink)
Outlaw In search of Law breaking Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Cyprus, Nicosia Posts: 627	Re: Meg Aluminium can "decaying"? Quote: (Originally Posted by Ben Field) Aluminium is a pretty nasty metal to put in seawater Galvanic corrosion - Wikipedia, the free encyclopedia Thanks for the link. Quote: (Originally Posted by EBT) its because you're attaching a different metal to the aluminum. Solutions are either to buffer the connection (put some rubber under it) or find a way to attach an anode to it (probably not practical). so it does happen? how do you get to fight this? isn't this worrying? do you have fotos for your precaution measures? Thanks. __________________ CMAS - IANTD - TDI Kamikazi Instrustor Trainer DIRRebreather Team Member ---------------------------- "Once an Outlaw, always an Outlaw"
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17th October 2007, 10:04	#5 (permalink)
UKSteve Still a novice... Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 557	Re: Meg Aluminium can "decaying"? My solution .. use a plastic scrubber housing : OK..I know I shouldn't... but couldn't help it!! Seriously, hope you are taking the same precautions with your Aluminium cylinders and not simply putting steel bands around them. You need to put a rubber layer between the two different metals otherwise the type of corrosion you have found is a great way to knacker the cylinder in a very short period of time. Please tell me you were aware of that already!!! Steve
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17th October 2007, 10:21	#6 (permalink)
*Beanie* Politeness officer Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,159	Re: Meg Aluminium can "decaying"? Quote: (Originally Posted by UKSteve) My solution .. use a plastic scrubber housing : OK..I know I shouldn't... but couldn't help it!! Seriously, hope you are taking the same precautions with your Aluminium cylinders and not simply putting steel bands around them. You need to put a rubber layer between the two different metals otherwise the type of corrosion you have found is a great way to knacker the cylinder in a very short period of time. Please tell me you were aware of that already!!! Steve you mean a bit like this __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk www.divelife.co.uk
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17th October 2007, 12:40	#7 (permalink)
Outlaw In search of Law breaking Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Cyprus, Nicosia Posts: 627	Re: Meg Aluminium can "decaying"? Quote: (Originally Posted by UKSteve) Please tell me you were aware of that already!!! Steve Seriously, i wasn't, but i am now!!! Thanks. __________________ CMAS - IANTD - TDI Kamikazi Instrustor Trainer DIRRebreather Team Member ---------------------------- "Once an Outlaw, always an Outlaw"
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17th October 2007, 12:50	#8 (permalink)
Meng_Tze 246 Bubbleless Cove Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: FL, USA Posts: 105	Re: Meg Aluminium can "decaying"? Galvanic corrosion does happen yes, but will it corrode through the material (Al)? In 200 years maybe (or whatever big number, point is; not in our lifetime under normal diving circumstances). It is not pretty on tanks or the meg can, but not a mechanical problem. If you want to make sure it does not happen, put a barrier between the dissimilar metals.
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17th October 2007, 13:13	#9 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,855	Re: Meg Aluminium can "decaying"? Quote: (Originally Posted by Outlaw) so it does happen? how do you get to fight this? isn't this worrying? do you have fotos for your precaution measures? Thanks. You want pictures of my rubber? Just use a piece of large inner tube. __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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17th October 2007, 13:26	#10 (permalink)
Ben Field CK+Shearwater Current Rebreather/s: Classic Kiss Other Rebreather/s: Sport Kiss Join Date: Aug 2005 Location: London, England Posts: 1,482	Re: Meg Aluminium can "decaying"? Quote: (Originally Posted by Meng_Tze) Galvanic corrosion does happen yes, but will it corrode through the material (Al)? In 200 years maybe (or whatever big number, point is; not in our lifetime under normal diving circumstances). It is not pretty on tanks or the meg can, but not a mechanical problem. If you want to make sure it does not happen, put a barrier between the dissimilar metals. How thick is the Meg can? It ate through some ali goodman handles I made in about 9months. Remember it doesn't need to make a hole just weaken it so it is easily damaged, it also does a good job of sticking thinks together. __________________ www.hugsac.org.uk Beware Fridge Suck
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