Rust in an aluminum 63???????

[dchango]

Here’s a weird question. Has anyone ever seen rust in an aluminum tank? I have a 63 that is coated with a layer of rust on the inside, and I can’t figure out how it got there. The history on the tank, it was tumbled and hydro’d due to some water and aluminum oxide corrosion build up late in 2009, it was used several times after that then sat for almost a year and a half or so. Earlier this year I decided to take a PSI course and learn tank inspection, being a have a bunch of tanks of my own, and may do it as a side job someday. Well, this never came up in the course. Could it be possible that when it was tumbled they didn’t clean all the media out? I don’t recall any noise coming from the tank, but this was my wife’s tank and really didn’t use it. I was going to try to tumble it myself, but decided to send it in and get it rehydro’d and tumbled. Again has anyone seen this before, if so what could it be from?

Thanks
Damon

 

[Brendon]

Rust? No... Corrosion yes. Rust is a reference to the oxidation of iron.

 

[redacted]

What was your reason for the re-hydro?

 

[dchango]

Rust is a reference to the oxidation of iron.

I agree...............

 

[dchango]

What was your reason for the re-hydro?

Not really sure, maybe just because it is very strange that rust (or what appears to be rust) is in an aluminum tank. I would rather be safe than sorry, and its only $40. Do you feel I’m over reacting?

Thanks
Damon

 

[halocline]

I would rather be safe than sorry, and its only $40. Do you feel I’m over reacting?

I do, and $40 for a hydro is quite expensive. Since you took the PSI class, I would think you'd have good access to information about what the rust-colored deposit in your aluminum tank is, and the best way to deal with it. Can you ask the person you took the course with? My guess would be rusty rinse water from the last tumble, or just rusty media and a less-than-perfect rinse.

Unless there's serious damage to the interior of the tank, I have no idea what the purpose of the hydro test is. I certainly hope that the PSI class dispelled the myth that hydro tests are needed after tank tumbling to remove surface corrosion.

When you find out, it would be interesting to know where the deposit came from.

 

[dchango]

I do, and $40 for a hydro is quite expensive. Since you took the PSI class, I would think you'd have good access to information about what the rust-colored deposit in your aluminum tank is, and the best way to deal with it. Can you ask the person you took the course with? My guess would be rusty rinse water from the last tumble, or just rusty media and a less-than-perfect rinse.

Unless there's serious damage to the interior of the tank, I have no idea what the purpose of the hydro test is. I certainly hope that the PSI class dispelled the myth that hydro tests are needed after tank tumbling to remove surface corrosion.

When you find out, it would be interesting to know where the deposit came from.

I’ve got a e-mail into Mark to see the he has seen anything like this before, due to the holidays I don’t expect a reply until mid week. I did look in the manual from the class and all it states for corrosion on aluminum is oxide and hydroxide nothing about any rust colored substances.

Yes, in the class he briefly spoke about some places requiring a hydro after a tumble. There is no legal requirement for practice, some places just want to make a little more cash and or feel more comfortable.

My issue on the rehydro is, this something I have never seen or heard of, not that I have all that much experience with these. I just know that aluminum doesn’t rust by itself so there is something missing . What it is I don’t know, that’s why I’m being extra cautious.

The $40 is the cost of the hydro and a tumble. I tried to rinse it with water and simple green, but it is firmly attached to the walls and bottom of the tank. I can tumble it myself, but if I’m going to take it in I might as well have them do it all. Well, I think I will throw it on the tumbler and clean it up and check it for any pitting. I’ll let know what I find out.



Thanks
Damon

 

[SeaCobra]

Do you know what tumbling media was used? What are the procedures for tumbling, rinsing and drying?

 

[dchango]

Do you know what tumbling media was used? What are the procedures for tumbling, rinsing and drying?

No I don’t, but I am going to check with them this week.

Thanks
Damon

 

[stilldivin]

You can check to see if it's rust with a magnet. If it sticks to the magnet, it's rust. Aluminum is non-ferrous (non-magnetic.) I have been told the tumble media is non-ferrous. I've also been told a hydro is necessary after a tumble because the tumble removes some of the metal inside the tank, and they want to make sure the tank will still pass a hydro. A shop I use in Santa Clara, CA. only charges $20.00 for a tumble and $35.00 for a hydro.