Doing hydro and visual separately

[JackD342]

If I recall the math correctly, it is a simple proportion. Extend the lever by 10%, you will increase the torque by 10%.

 

[Seaweed Doc]

When I used to have tanks hydro'd at the local fire extinguisher company, my LDS would not require a visual until a year after they hydro. Not sure that's common practice nation- or world-wide.

I don't hydro tanks unless I plan on using them soon. I wait until I need them. (Let's just say I've got TAD. Tank Acquisition Disorder. Too many tanks for current needs, but might need 'em all some day.)

 

[JackD342]

I can't speak to what standards my hydro place applies for a visual. And if there isn't an in date sticker on your tank, good luck getting fills. And don't ask me to put my sticker on, without having personally performed the work.
On a new cylinder, the MFGR sticker fine print says it was visually inspected, and I used to send it out the door like that.
Now I do my own visual for that customer first - it is a month or two fresher, eliminates some potential sticker hassles, and if there is an actual production defect observable via inspection, better I find out sooner than later.

 

[Scuba-74]

There are a lot of dependencies here. If you are shipping cylinders, you will need to remove the valves. Compressed air is hazmat.
If local, you are probably fine. Hydro providers don't all run their businesses the same way. Mine wants all valves and boots removed before they ever get the tank.

If I sell, it would definitely be a local pick up. It would be financially prohibitive to ship these tanks. Plus we have a relatively active market for steel tanks around here.

Remember the hydro is every 5 years. So if you have one done, then sit on them for a year or so before selling them, your investment in that hydro is devalued. I would have the visual done now though if you are thinking of offering for sale, so you know if that (usually?) less costly procedure is passed. I always do a vis before sending a cylinder to hydro. Whether pass or fail, the hydro place gets paid once the work is done, and I don't want to run up any avoidable expenses for myself or my customers.

The visual expires in a year, so it will devalue even faster. Besides, potential buyer may prefer to get the "official" visual with a sticker done where they do the fills.

If they don't have a VIP sticker, the dive shop who does the VIP is going to take the valve off anyway.
The big thing is that these shops don't always have new o-rings for scuba valves so you need to change that first before filling. Again, if you take it to a dive shop, when they do a VIP they do or should change the o-ring. Always ask for your old o-rings back if they don't do it as standard as proof that it was done properly

Good point. My dive shop does that, but they mentioned that some of the other ones don't.

 

[rhwestfall]

• M1 = M2 x L1 / L2

 

[Johnoly]

.... I'm considering getting them hydroed first for piece of mind.....

You sound like a very trusting person.Why spend money on a hydro or vip if you haven't YOURSELF looked inside the steel tanks to see how much rust is in there? (all steels have some rust). You wouldn't buy a used car without driving it first would you?

I think you're missing the very 1st step, look inside the tanks even if you have to drain them. I pull the valves on all 4 of my steels every 6 months and drop a set of white christmas lights inside just to see what the progression is on rust and if any moisture happened to get inside. Hydro guys will pump anything, they don't care if there's a pocketful of rust like usual on welding tanks, it's not their job. It's pumped and passes or fails, you pay either way. Instead of spending money, you may be getting a refund..........from the seller!

 

[Scuba-74]

You sound like a very trusting person.Why spend money on a hydro or vip if you haven't YOURSELF looked inside the steel tanks to see how much rust is in there? (all steels have some rust). You wouldn't buy a used car without driving it first would you?

I think you're missing the very 1st step, look inside the tanks even if you have to drain them. I pull the valves on all 4 of my steels every 6 months and drop a set of white christmas lights inside just to see what the progression is on rust and if any moisture happened to get inside. Hydro guys will pump anything, they don't care if there's a pocketful of rust like usual on welding tanks, it's not their job. It's pumped and passes or fails, you pay either way. Instead of spending money, you may be getting a refund..........from the seller!

I see your point, and it's a valid point. If the tanks were empty at the time of the sale, I would've pulled the valves and looked inside with a little flashlight. Also, if the seller asked for more than they did, I would have made the deal contingent on passing the hydro/viz, as I did when I purchased my other two steel tanks.

But assuming that I bought them as is, do you recommend draining and looking inside before sending them to either hydro or viz? I wouldn't even know what I'm looking at I'm afraid. You said it yourself that all steels have some rust. How would I know how much rust is too much?

 

[Johnoly]

... made the deal contingent on passing the hydro/viz, as I did when I purchased my other two steel tanks.

Buying tanks from friends is easy cause you know them. Buying from 'unknowns'..I'll insist on seeing inside and will pay for the fill I want to walk away (with inside picts to share)

.But assuming that I bought them as is, do you recommend draining and looking inside before sending them to either hydro or viz?

YES !! You have nothing to lose by draining and looking inside now. If the tanks are garbage you'll save the hydro and vip cost and can go back to the seller for adjustment

.I wouldn't even know what I'm looking at I'm afraid. You said it yourself that all steels have some rust. How would I know how much rust is too much?

Glad you Asked !!! ScubaBoard is all about sharing knowledge, stories and helping others (well and roger's polls .. )


Here are two pictures of the insides of my tanks. One is 'marginal', the other is 'good' and you can see the difference and what to look for.

This 1st one is alot of rust on the walls and really at the bottom. Since it wasn't 'pitted' on the bottom ,,it passed vip after a deep 24 hour tumbling with ceramic stone media with 2 cups of Simple Green and a followup cleaning and rust preventative coating and warm air drying.

This next one you can see Just has some spots and slight surface rust. I had the shop use a wire wisk and they removed the rust, put in the rust preventative and warm air dried it. This is the kind of tank you want to buy used. Hope these pictures help you look inside your tanks and make a decision how much rust is inside.

 

[Bob DBF]

When going to look a a used tank I want to buy, I bring a light to drop in the tank, one of my tanks with air, and a transfer whip. I haven't been denied a peek, and when done I charge the tank to 200# or so. And a transfer whip is quite handy for other tasks as well, a great addition to any dive locker.



Bob

 

[Scuba-74]

...Hope these pictures help you look inside your tanks and make a decision how much rust is inside.

Wow, they sure will! Thanks posting! I can see that my idea about sending them for hydro wasn't the greatest...

So the first picture - is it before or after the tumbling? If before, do you think it would have failed the visual as shown in the first picture?