PST HP100 Internal Rust

[Spg01]

Hey all,

Last year I was given a PST HP100 tank (cylinder....) I brought it to my usual shop to get a hydro and vip. When they took the valve off to check the tank it looked beautiful inside, no rust or anything. It came back from hydro with no problems.

Well my 1st vip is due on it and when they broke it open this time there was rust. The rust looked more like spots rather than the flash rust I have been reading about tonight. The tank was not completely covered with rust spots, but there was enough rust to take notice. The shop guys said it is somewhat normal for this to happen with steel tanks and it needed to go get tumbled. So I said OK go for it.

In the last year I have probably put 40+ dives on that tank with a handful being boat dives. I also have an xs hp100 that is due in the next month or so, but I like the PST better. I am hoping the XS tank does not have the same problem.

So from what I have read so far tonight on the forum some say rust is somewhat normal with a handful of people saying they have never had rust :confused:

This next year I am planning to only have it filled at the shop and see what happens. I don't really want to have my tank tumbled every year. I did see tank whips mentioned in other threads, but they run ~$70 from what I have seen.

Any thoughts?

[drbill]

I had a PST HP120 fail its first VIP after its second hydro due to serious rust issues... most likely due to about 300 SoCal boat dives during the intervening year.

[Spg01]

Can you tell the problem by the type of rust? Or is rust just rust no matter how you look at it?

[spectrum]

It comes with the territory with any steel cylinder.
1) The drying after the hydro may not have been perfect
2) You may have gotten a wet fill
3) You may have had some water in the valve that got pushed into the cylinder during a fill. Always blast the valve before presenting to fill.
4) A wet fill may have been botched.

Words are deceptive but what I'm reading sounds like a quick spin with a cylinder brush may be all that's needed. much less troublesome than tumbling.

I have had a few show up with notable speckles that brush cleaned and were then stable. This doesn't sound like a brand issue, just common steel cylinder maintenance. I think I have had 2 or 3 cylinders brushed in roughly 36 steel VIPs.

Pete

[deepstops]

Sound advice ^^^^^

[Peter_C]

I just whipped three tanks (Non of them are mine), but two of them need to be tumbled (In the process of a DYI tumbler). Total cost for the whip I think was around $5.00. I used an aluminum rod from Home Depot, plus a 1/4 stainless cable unraveled on one end. With a two hose clamps to hold it in place and some duct tape to cover the hose clamp. Then a plastic sleeve to protect the neck threads.

[Spg01]

I just whipped three tanks (Non of them are mine), but two of them need to be tumbled (In the process of a DYI tumbler). Total cost for the whip I think was around $5.00. I used an aluminum rod from Home Depot, plus a 1/4 stainless cable unraveled on one end. With a two hose clamps to hold it in place and some duct tape to cover the hose clamp. Then a plastic sleeve to protect the neck threads.

That sounds a lot better than the $70 one I saw. It sounds like sooner or later this will happen again and your idea has a better price tag.

[Spg01]

It comes with the territory with any steel cylinder.
1) The drying after the hydro may not have been perfect
2) You may have gotten a wet fill
3) You may have had some water in the valve that got pushed into the cylinder during a fill. Always blast the valve before presenting to fill.
4) A wet fill may have been botched.

Words are deceptive but what I'm reading sounds like a quick spin with a cylinder brush may be all that's needed. much less troublesome than tumbling.

I have had a few show up with notable speckles that brush cleaned and were then stable. This doesn't sound like a brand issue, just common steel cylinder maintenance. I think I have had 2 or 3 cylinders brushed in roughly 36 steel VIPs.

Pete

Thanks for the info. I assume the cylinder brush is the same as the whips I have heard about? Similar to a few posts down from yours?

Thanks again.

[dannobee]

When I read the first post saying the tank was perfect inside, then a year later it had rust, the first thing I thought was, "hmm, I wonder if he's diving off of So Cal dive boats."

Then I noticed his location.

It's a compressor filter/condensate drain issue. The fills are wet.

Dedicate a tank to boat diving and live with the fact that it'll require tumbling. Or just use one of the boat's tanks and leave yours at home.

[halocline]

It only takes one wet fill and you'll have some rust. Luis H has some sort of brush that he uses on steel tanks and swears by it.

[Peter_C]

Thanks for the info. I assume the cylinder brush is the same as the whips I have heard about? Similar to a few posts down from yours?

Thanks again.
Yes they are the same thing.

I have read where many prefer to use acid over tumbling to clean the rust out, but I really do not want to keep 5 gallon buckets of acid around, nor do I want to have to dispose of the remnants. (Although my gal is a chemist and I could ask her to do it!)