Questions about VIP process

[Karpie]

I'd love to get some input on my recent (and first) experience in getting tanks VIP'd.

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SCENARIO:

I picked up two old Catalina AL80s for $25. They looked pretty rough, with paint hanging off in giant sections, and plastic netting and boots that had potentially never been removed. Earliest hydro dates were 99/early 2000s. I figured I could always sell them for scrap if they didn't pass VIP/hydro.

I took them directly to the shop. I didn't remove the netting or boots, thinking it'd be better to for them to evaluate them "as is". I let them know I didn't care about the netting and they could be cut off.

I came in the check if they were ready, and they had finished the hydro and just needed to do the VIP on the last tank. I watched them inspect the internals with the light and install the valve. They cut off the netting for me right then and gave them back to me with a new hydro stamp and VIP sticker. (I can't remember if I got any post-inspection/testing paperwork.)

A few weeks later, I finally have the time to knock the boots off, scrape away lifting paint with a plastic scraper/plastic brush, and give them a good scrub-down with a green brillo pad. It was pretty gnarly, though I'm not sure what might've been corrosion byproduct vs salt. Afterwards, I look them over and find some pitting under the boot area. My guess is in the 0.5-1 mm range?

QUESTIONS:

Was fine to have given them to the shop as is, assuming they'd remove whatever they needed to perform the external VIP? I'm not sure about about the expectations/etiquette for it. In hindsight, it would have been better to remove the netting and boot and a give them at gentle cleanup beforehand. I could've questioned those things still being installed upon pickup, as well.

Should I take it back to the same shop for another VIP, now that the externals surfaces are fully exposed? Or should I just write them off as a place for tank VIPs and get them VIP'd at another shop? (By the old stickers, the same shop had performed the previous VIPs).

The Luxfer VIP manual available on their site suggests their tanks should be condemned with pitting 0.76 mm or greater. These are Catalina tanks, but I'm wondering if I should just slowly bleed the air from the tanks, remove the valves, and take the tanks straight to the scrapyard.

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I really appreciate any feedback or advice you might have for me! I'm still learning and want to make sure I'm doing things right.

 

[Alaskan Scuba Dude]

A picture is worth a thousand words. If they stamped your tanks with a punch using a hammer I wouldn't be concerned with the pitting.

 

[runsongas]

max pit depth for luxfer is 0.06 inch or 1.5mm in the base, so if these are confined only to the bottom, you likely are still ok

i would have not taken a brillo pad though, as you likely removed some aluminum oxide too and that area will now have to recorrode a bit until it passivates

 

[Bob DBF]

I came in the check if they were ready, and they had finished the hydro and just needed to do the VIP on the last tank. I watched them inspect the internals with the light and install the valve.

Does the shop do their own hydros, or do they send them to a hydro shop?

 

[diveservice]

As stated earlier, A picture is worth a thousand words. The base of an aluminum cylinder is thicker than the side walls. But they should have removed the netting and boot for a proper external inspection. They could then have wiped away any corrosion or obstruction, for a proper measurement. If anything, take it back to the shop and use their Damage Reference plate and see if any single point corrosion exceeds .06" / 1.5mm. They can also assess for general corrosion in an area to see if it affects anything. General corrosion has a slightly different standard. Guessing it does not have excessive surface corrosion since it passed hydro, but you dont know until you check. Otherwise, you got a good deal for $25