Would you consider buying a used tank?

[Ari]

Why do you make difference between AL and ST? Rust concerns?

Ari

 

[WreckWriter]

Originally posted by Ari
Why do you make difference between AL and ST? Rust concerns?
Ari

Yea. Rust never sleeps ya know

Also, it seems to me that steels are more likely to have been significantly overpressurized in the lifetime (although I think most tank explosions have been aluminums).

Tom

 

[FredT]

Originally posted by WreckWriter


Yea. Rust never sleeps ya know

Also, it seems to me that steels are more likely to have been significantly overpressurized in the lifetime (although I think most tank explosions have been aluminums).

Tom

This seems a bit backward to me.

1. A steel tank's metalurgical defects, if any, will be obvious on inspection of the hydrostatic test data (NOT just does it have a stamp?). This is why you always want the burette readings when getting a hydro! Past abuse you should be concerned about will show up in the data, if it's not there what ever abuse the tank was subjected to did it no harm. Hydro data on an Al tank generally gives no indication of past excesses. The work hardening properties of 6000 series AL tend to mask it in the data.

2. Steel is a MUCH more forgiving metal than Al in both loading cycles and heat response.

3. Corrosion and extreme over stress issues in/on a steel tank are immediately obvious during visual, and can ususally be easily addressed and further damage prevented. Cl- ion Corrosion cells in an AL tank WILL kil it once the cell is established. The only question is when. There is no way to stop it. Al Stress cracking is often invisible and undectectable until it either fails, or makes it to a surface where it can be found.

4. If the shop tank monkey overtorques an AL tank valve the tank neck is permanently damaged. Over torque the valve on a Steel tank and the valve yields. Valves are a LOT cheaper than tanks.

5. Used AL tanks are CHEAP and quite common, but new bottles are dirt cheap too. Used HP Steels are a significant percentage of new $s. but the first cost is enough to make the difference worthwhile.

FT

 

[WreckWriter]

Originally posted by FredT
This seems a bit backward to me.

I never claimed it was based on scientific fact! Your points are all excellent in favor of practices opposite of mine.

Tom

 

[FredT]

Originally posted by WreckWriter


I never claimed it was based on scientific fact! Your points are all excellent in favor of practices opposite of mine.

Tom

OK. I didn't mean it as a ping, but I've spent too many years in the engineering game. It's caused me to expect some logic.

FT

 

[Ari]

are more common than bad used steel tank ( or at least this is how it looks).

Don't mind me. I am just one more crazy engineer.

Ari

 

[WreckWriter]

Originally posted by FredT
OK. I didn't mean it as a ping, but I've spent too many years in the engineering game. It's caused me to expect some logic.
FT

I generally operate on logic also. For whatever reason, I've just always been funny about used steels. I think its because I really haven't had too much exposure to the newer steels, mostly just older ones.

I don't like folks to bring bananas on boats either

Tom

 

[FredT]

Originally posted by WreckWriter


I don't like folks to bring bananas on boats either

Tom

That sounds like it has roots in the same soil as the one we developed while I was in school.

"Nude sunbathing is prohibited on the main deck until the spearguns are stowed." Bernadette was a serious distraction that contributed to several injuries. Since she didn't dive she made a wonderful "boat watch" while we were down though.

FT

 

[WreckWriter]

Originally posted by FredT
That sounds like it has roots in the same soil as the one we developed while I was in school.

"Nude sunbathing is prohibited on the main deck until the spearguns are stowed." Bernadette was a serious distraction that contributed to several injuries. Since she didn't dive she made a wonderful "boat watch" while we were down though.
FT

I don't know the roots of the banana thing for sure. It's pretty prevalent among fishing boats in the Upper Keys though. Some even have "No bananas" signs. My theory is that it started with boats carrying cargos of bananas finding their holds infested with spiders, snakes, and other beasties which had been living in the banana bunches.

I like yours better!

Tom

 

[Shadow]

I recently bought a steel 72 tank on e-bay. The seller stated that the tank was 3000 psi, and a US Divers tank. The tank was in current hydro (good until 2004), and the picture on e-bay looked good. I won the bid at $100.

Well, when I went to pick it up (130 miles away), I found that it was only 2250 psi. Also, there seemed to be a lot of uneven spots underneath the paint. It was stamped PST, so I think it was a Pressed Steel Tank, which I don't believe are painted by the manufacturer. The first hydro date was 1961. I specifically wanted a 3000/72 tank (I thought it was a Faber from the paint and pressure). The tank did not have DOT or CTC stamp, either (don't know when those stamps came into use). Unfortunately, the seller had left the tank at a friend's house for me to pick up, so I couldn't deal with him directly. I left the tank, and am now trying to get a refund.

I would buy a used tank, but never one I haven't actually seen and had checked out for myself. Also, if a tank is manufactured after 1991, it must have TC (Transport Canada) approval, or it cannot be filled in Canada. So, lots to look for when buying a used tank. $2 at a garage sale is worth taking a chance. But I'm not too eager to throw away $100 on a tank that isn't what I was sold. I doubt I would ever buy a used tank on e-bay again.