Fine ‘rust powder’ inside 1st stage…

[noj3333]

So I’ll refrain from posting names (I don’t want the dive charter, or service center I used to impact opinions, but I will post their info in a short period of time) but I need some advice from the board on this…

This past winter I did some diving and used a steel tank operator, this was the only time my regs have been on steel tanks. Last week I thought it’d be wise to have these regs serviced so I just sent them out to be inspected/ serviced. The main reason I wanted them serviced was because they were sourced from three different spots and I wanted a fresh slate with them so I know what I have (the primary second stage was bought used on SB, octo was brand new, and the first stage was used, I got it from a shop that serviced it before I bought it).

I just received a call from the service shop and they said my first stage wasn’t locking up in the 140-145psi factory range. They said they were surprised I wasn’t getting a free flow from my primary, as it was creeping to around 160psi before it would settle it. They explained that they checked the seat expecting some sort of issue, but instead they found ‘fine rust powder’ all over the seat, and throughout the 1st stage. It was their opinion the rust powder had more than likely moved throughout the primary and octo as well, so they should also be inspected/ serviced to ensure they’re fit for use.

I fully trust the service department, so unless people call bull sh*t in mass I’ll maintain my trust in them. My questions more revolve around the use of the steel tanks… is this a common issue? Is there anything that can be done to prevent future issues like this? I’m inclined to post a write up to save fellow dives from the same fate due to the operator I used (I'm currently inclined that it was their tanks that caused this issue)… I really don’t like doing that but I think it may be appropriate here…

Opinions and advice????

 

[redacted]

If you inspect your first stage filter often, you may catch this kind of problem early. Hoses may need to be cleaned also.

 

[noj3333]

According to the shop there was no coarse rust in the filter, just fine rust powder. I asked about the hoses, and they said they'd be cleaned as part of the service.

 

[g1138]

If the tank is very very filthy then yes you can get rust powder through the filter. But the tank would have to be very far gone. The more rust, the possibility that the rust will powder up real fine. 2400psi pushing that fine powder through the filter can cause it to bypass into the 1st stage and beyond.

Flash rust does happen to steel tanks and is normal. However when that flash rust builds up to "rust" it will flake off or even chunk. Chunks will break as the tank is moved and jostled and that is where you get your fine powder.

One thing that can help check this yourself is to always purge your tank for a split second. Oil, rust, or other smelly contaminants in high concentration can be either be seen or smelled when you do this. Then after you connect your reg, smell the air coming from the 2nd stage.
Air from the tank should smell clean. Air from the 2nd stage should either smell clean or like silicone.

No need to hover your nose near the valve, just purge and then move close and sniff.
Or if the valve is pretty decent you can let out a small creep and smell it.

On disassembly also look at your 1st stage filter and note if it has changed color compared to prior assembly.
Black = oil
Green = moisture corrosion, from a prior day of diving
Brown = rust
White = Aluminum oxide from AL tank corrosion.


Only advice, tell the shop you got the tanks from.