doubles/tire intertube

[Derek S]

Well, it true. Alum tanks have a coating, the bands have to be removed once a yr when the tank should be inspected. But someone, somewhere, read his science book and is now worried that his Alum tanks are going to spontaneously corrode underneath his very eyes. There are bigger issues to worry about.

I know. My AL80s don't have anything on them underneath the bands. :14:

 

[LittleFish]

Well, it true. Alum tanks have a coating, the bands have to be removed once a yr when the tank should be inspected. But someone, somewhere, read his science book and is now worried that his Alum tanks are going to spontaneously corrode underneath his very eyes. There are bigger issues to worry about.

With the chance of sounding like a “weenie”, this does not sound like a non-problem. It sounds like a small problem with a very simple solution. One that does not, as far as I can tell, create any new problems. If you have to check under the bands every year for galvanic corrosion, and you find some, what do you do then? Why not use the innertubes and eliminate the galvanic action all together. I am sure there is something I am not experienced enough to know about this, so please enlighten me.

 

[wreckchick]

I'm speaking with precisely zero experience with this specific issue, but it seems to me that putting an innertube or anything else under the bands could potentially lead to salt water getting trapped against the tanks (if one was to dive the ocean) which is far nastier as far as corrosion than the galvanic corrosion with the dissimilar metals.

Again, I could be talking from somewhere other than my head.

Rachel

 

[O2BBubbleFree]

Yeah, I think that would make the bands slip. I have put packing tape on the inside of the bands, and it works well.

Rubber will slip, but packing tape won't? You're gonna have to explain that one to me.

 

[JeffG]

With the chance of sounding like a “weenie”, this does not sound like a non-problem. It sounds like a small problem with a very simple solution. One that does not, as far as I can tell, create any new problems. If you have to check under the bands every year for galvanic corrosion, and you find some, what do you do then? Why not use the innertubes and eliminate the galvanic action all together. I am sure there is something I am not experienced enough to know about this, so please enlighten me.

For you, I would recommend putting on the innertubes.

 

[WaterDawg]

Rubber will slip, but packing tape won't? You're gonna have to explain that one to me.

Im not telling you to do it, so no, I don’t. But that’s right packing tape on the bands have not slipped a bit.

I was buying some tanks that used to be doubled up and noticed some light pitting where the bands where, I went home and took mine apart and found a ton of corrosion, a lot of it was just from the salt water I presume, and some from dissimilar metals. Now Im not very good at rinsing gear, but the tanks were less than a year old.

I cleaned the corrosion of w/ a razor and some other stuff and decided to put the tape on after seeing some other tapes applied directly to the tank slip. I cked it 6 months later and the corrosion was minimal, so the way I look at it…it works.
At the time I was in a tropical island and diving salt water exclusively (and lots of it) so it could have just been salt water corroding it, but like I said the tape helped

 

[Meng_Tze]

Meng-Tze, how fast does it occur? Thanks.

The question is not how fast 'it occurs', basically instantly, especially when diving salt water... but it is not a big issue at all. AL does not corrode through that easily (well at least not in our lifetime). You will basically get a bit of corrosion, AL will 'seal' itself and that will be the end of it. Just put the bands on and go diving.

 

[LittleFish]

For you, I would recommend putting on the innertubes.

I do not understand your comment. I am asking this question because the topic is about addressing corrosion. There seems to be galvanic corrosion occurring and I would think, perhaps incorrectly, that the DIR methodology is to address all potential failure points. Again I may be way off here, but it seems to me that innertubes, acting like gaskets would not only not slip, but if cut the correct width, actually keep water, and salt, from getting between the cylinder and the band.

I am open to being corrected in my thinking, but it helps to understand where I went wrong if you provide back-up for your position.

Please keep in mind that I am not trying to get anyone to turn on their flamethrowers. I just want to understand the rational behind the decision, and when you get right down to it isn't understanding the reason for each piece of equipment, it's configuration and relationship to every other piece, the DIR way.

Thank you for your most valuable insights,
LF

 

[rmannix]

Dissimilar metals in salt water need not even touch each other to cause galvanic corrosion.
Insulating the bands does nothing but make them fit tighter.
Try wearing zincs instead of weights.

 

[Hawkeyegregg]

I'll second the fact that the metals do not need to be touching for corosion to occur just to drive it home. I'll also second the zinc notion. Find a way to attach a hunk of zinc to or near the band and any problem that does exist will go away as long as you replace the zinc when it coorodes significantly.