Tanks tumbled ... normal for a 7yr old Faber ???

[Gandalf-the-Diver]

Hello hive, just over 2 yrs ago, I purchased a pr of 5yr old Faber, 100HP tanks, with fresh Hydro and Vis. Last yr, both tanks passed their vis, this yr, I was told both tanks needed tumbling. I have just under 300 dives in 25 months, and have only used my local dive shop for fills. Is getting a 7yr old steel tank tumbled, normal ???

 

[Still Kicking]

It depends.....one wet fill is all it takes (compressor not properly drained is the most common culprit).

However, there are overzealous inspectors who want to tumble every tank with light flash rush (revenue enhancement perhaps?)

IMO tumbling is only warranted if there is chunky and/or loose rust because a) you don't want to be breathing the dust and b) the inspector has to see what kind of pitting is under the chunky rust.


I would ask to see a pic of the inside or take ask to look for yourself if they haven't been tumbled yet.

 

[Gandalf-the-Diver]

It depends.....one wet fill is all it takes (compressor not properly drained is the most common culprit).

However, there are overzealous inspectors who want to tumble every tank with light flash rush (revenue enhancement perhaps?)

IMO tumbling is only warranted if there is chunky and/or loose rust because a) you don't want to be breathing the dust and b) the inspector has to see what kind of pitting is under the chunky rust.


I would ask to see a pic of the inside or take ask to look for yourself if they haven't been tumbled yet.

The tanks have only been filled by one compressor, their entire lives. I purchased the tanks from my LDS, and they were former rental tanks. I have had an unlimited air card, the entire time I have owned them. The person who did the vis inspection, is also a sometimes dive buddy.

 

[halocline]

Try to get a look inside the tanks, if the guy is a dive buddy, he'll probably let you look. It's not rocket science, just look to see if there is significant rust. You can spend a little time finding descriptions and maybe some photos online of what 'flash rust' looks like vs real corrosion. Basically, when tanks are hydro tested, they are filled with water. They then must be drained and the preferred way to do it is to flush them with clean very hot water that evaporates quickly and leaves little or no rust, and blow them dry with a compressed air wand. Sometimes steel tanks are also treated with a rust inhibitor, but I haven't found that necessary.

Since 95% (at least) of hydro testing facilities' business is welding, fire extinguishers, etc, they typically don't care about flash rust from the testing procedure. Scuba tanks are holding breathing gas at much higher pressures so they need to be very clean.

Since you didn't look inside the tanks when they came out of hydro, you don't have a reference for the condition of the tanks then vs now. But, if there is any real corrosion or pitting, and the only place you've had them filled is at this shop, and you have never let them get completely empty, then for sure there is a problem with the shop's compressor.

One last thing, let's say that you looked inside and saw a light coating of flash rust. You can brush that out; you just get a steel brush on a long wand and scrub away. There are also 'whips' which are basically strips of adhesive cloth on a long shaft that fits into a drill, and those can do a good job cleaning out flash rust. Both of these options are less aggressive than tumbling. Tumbling isn't bad for a tank as long as the media isn't too aggressive and they don't overdo it.

 

[Johnoly]

Last yr, both tanks passed their vis,

Before bringing the tank(s) in for the annual Vis >>> It's perfectly fine for you to :
* completely drain the tank
* Remove the valve - usually with a slap of just your palm-no tools needed
* Peek inside with a flashlight
* Take an inside picture with your phone
* Replace the valve & bring it to the shop for VIS
.............. (below pict is one of my Faber LP108s )

 

[-JD-]

Also, you can acid-clean them yourself with minimal equipment.

Phosphoric Acid for rust cleaning / inhibitor: Mixture and Procedure

I just got a few tanks back from hydro today. Inspired by a recent thread on tank whips and a post recommending phosphoric acid instead by @rjack321 (and confirmed by @rob.mwpropane ), I decided to give it a try. It seems that many people are using the mixture and proportions recommended in...

scubaboard.com

 

[ScubaBunga]

Try to get a look inside the tanks, if the guy is a dive buddy, he'll probably let you look. It's not rocket science, just look to see if there is significant rust. You can spend a little time finding descriptions and maybe some photos online of what 'flash rust' looks like vs real corrosion. Basically, when tanks are hydro tested, they are filled with water. They then must be drained and the preferred way to do it is to flush them with clean very hot water that evaporates quickly and leaves little or no rust, and blow them dry with a compressed air wand. Sometimes steel tanks are also treated with a rust inhibitor, but I haven't found that necessary.

Since 95% (at least) of hydro testing facilities' business is welding, fire extinguishers, etc, they typically don't care about flash rust from the testing procedure. Scuba tanks are holding breathing gas at much higher pressures so they need to be very clean.

Since you didn't look inside the tanks when they came out of hydro, you don't have a reference for the condition of the tanks then vs now. But, if there is any real corrosion or pitting, and the only place you've had them filled is at this shop, and you have never let them get completely empty, then for sure there is a problem with the shop's compressor.

One last thing, let's say that you looked inside and saw a light coating of flash rust. You can brush that out; you just get a steel brush on a long wand and scrub away. There are also 'whips' which are basically strips of adhesive cloth on a long shaft that fits into a drill, and those can do a good job cleaning out flash rust. Both of these options are less aggressive than tumbling. Tumbling isn't bad for a tank as long as the media isn't too aggressive and they don't overdo it.

I had one of my tanks come back from hydro soaking wet inside. I also helped the LDS one day after my VCI cert and found one (out of like 20 tanks) missed the drying rack and was very wet inside. It happens - since I have my vci, I now only have a hydro done and have a good look before I put the valve back on. As mentioned, it only takes one bad fill or a bad hydro not dried fully. I now have a whip and a home made tumbler for any situation.