VIP Inspectors: Identifiable vs Identified

[rjack321]

Ah, I misunderstood.

Yea 3AL standard 2015psi tanks are not common in scuba. Only AL14s were ever made. 2015 psi-s are very common in O2 service though.

Of course the wall thickness for 2015 vs 3000 psi service is wildly different. So no surprise in a 2015psi tank the allowable pit depth would be shallower. The cheat sheet from my PSI class lumped all "3AL" standard tanks into one category - forgetting that some 3ALs have vastly thinner walls and that those allowable pit and line corrosion limits only apply to thicker walled 3000psi service cylinders. I didn't think about it either and was slightly on autopilot when I checked the AL14 I had. The pit was 1/2 the depth of the allowable standard in a 3AL3000 tank so I brought it into hydro. But (duh) it exceeded the maximum pit depth for a 3AL2015 and they failed it. I'm glad they caught my mistake. I still have another AL14 but it's pristine thankfully.

 

[Diving Dubai]

Tumbling does not remove intact material, it is removing corrosion / oxidized material yes.

Ahh gotcha

In my mind I was visualising a deburring/ polishing tumbler.

Yup, familiar with simple Ults for thickness gauging, used to write NDT procedures, and have found a crack in teh neck of a steel cylinder using Eddy Current

(Cue the posts saying its not possible)

As a bit of trivia a really good method for paint removing - and I suppose instead of tumbling, is sponge blasting

Basically small pieces of sponge are impregnated with grit, and fired at the component - the sponge however deforms on impact so the medium is very delicate, yet easily removes paint. Originally designed for car alloy wheel cleaning, we (in aerospace) developed it further so we could paint strip Carbon Fiber components without any damage to the carbon fiber (and I do mean zero damage - you can imagine the testing and certification process we went through)

Different coloured sponge is different grit, and you can vacuum up the media afterwards and re use.

 

[Jeremy Williams]

Hi Jeremy,

There most certainly is reciprocity. The individuals followed the industry guidelines for successfully getting trained to VIP tanks. RSTC, TDI, and PSI deserve reciprocity for their training services through their individual VIP cert holders. I think it is appropriate for an LDS to perform spot checks on cylinders that are VIPed by an unknown source. But, flat out reject the VIP is ludicrous. Pop the cork and look inside the tank. That's all it takes.

Since this is the Internet and all we have are words, I think you are seeing something and calling it reciprocity when it is not... at least by my understanding and definition...

Reciprocity is what occurs when two organizations grant the same privilege and they agree to treat the privilege granted by the other the same as if they granted it themselves. Simple examples, like basically all dive shops honoring all c-cards for basic dive privileges are easy. There are more complex examples of this in the industry, such as Shop A who works with Agency A (say, SDI) accepting a diver's c-card (say, AOW) from Agency B (say, PADI) as meeting the prerequisites for a class/certification (say, Nitrox) that is being offered. Shop B would do exactly the same if the agencies were reversed. Another example, as we've dfiscussed here, is VIP stickers. Shop A's stickers are good at Shop B and vice versa. Examples from government include things like marriages, drivers licenses, and handicap parking permits. Conditional examples include things like concealed carry permits for handguns, where the permit granted in my state is valid in many but not all other states in the US.

Reciprocity means that BOTH organizations are granting a privilege and BOTH organizations are honoring the grant that the other has made. The two organizations are peers. Individuals performing VIPs do not have a reciprocal relationship such as the one I'm describing. I see that as the source of the problem. Individual inspectors who are doing on their own VIPs and the VIPs of their buddies are engaging in custom with the dive shop and are not peers. Again, they are customers. They buy a class, they earn a certification, they perform an inspection that the shop used to perform, and then they try to buy a tank fill for that tank.

If the tank seems fine (and if not then all bets are off regardless), I think that the lack of reciprocity is the only objective difference between a VIP sticker from what appears to be a random dive shop elsewhere in the US and a VIP sticker with the customer's name and certification number for a VIP that was allegedly performed by the customer.

 

[2airishuman]

Interesting direction the thread has taken.

I find that policies vary widely. I find there to be value in maintaining a good relationship with a small shop. I have never had problems getting fills when I need them, but I can appreciate that the situation can be awkward in areas where there is little choice of dive shops.

Some of us live in small apartments and condos with no place for a compressor. I just love it when people say “get a compressor.” Living small allows lots of disposable income for diving.

There are many ways to deal with air logistics in remote areas or in other situations where it is expensive or time consuming to get a fill.

* You can have many cylinders. I have around 20. Typically I get 15 fills at a time, and can plan to get fills at a time that works for me and from a shop that I trust.
* You can obtain air in K or T size industrial 4500 PSI or 6000 PSI cylinders and fill your dive cylinders from them. Not common but there are situations where it works particularly if you have friends at a location that gets regular deliveries of other industrial gasses. You maintain a cascade with the Ks or Ts, fill your dive cylinders when you want, and have the industrial gas guy swap empties.
* A variation on that is that you can get a cascade trailer.
* You can use a portable compressor for fills at or near the dive site, i.e. in the parking lot.
* If you have a boat, you can use a portable compressor on your boat, or install one permanently below decks.
* You can form a club, formal or informal. It is not unusual for 2-4 people to purchase a compressor together and keep it in one member's garage or small business. Larger groups can sometimes find free space with 3 phase power especially if there is a public safety or other charitable aspect of the group's mission.
* There are still people who manage to get fills at a firehouse. Firehouses often have dive teams and therefore pump Grade E

 

[lowviz]

As a bit of trivia a really good method for paint removing - and I suppose instead of tumbling, is sponge blasting

So is crushed walnut shells: Walnut Shell Blasting - Composition Materials Co.

 

[Diving Dubai]

So is crushed walnut shells: Walnut Shell Blasting - Composition Materials Co.

Far too harsh for some applications

Been there - tested that, worn the Tee shirt out

 

[rhwestfall]

Isn't there also dry ice and talcum powder blasting methods?

 

[rjack321]

Isn't there also dry ice and talcum powder blasting methods?

My hydro shop has a variant of this, I think they use baking soda. It can (sometimes) work pretty well on those annoying epoxy liners in some lp72s. My media at home has never been able to remove that, but my hydro shop could with their soda blaster. I had to trust that it didn't alter the walls of the tank. I figured as an very high volume DOT inspected hydro shop they would know. I think they charged me $5 which is less than the cost of burning up my tumbler motor for sure.

 

[rhwestfall]

Yeah, I guess that was what I was thinking. I know dry ice is used. Colleague uses it for antique boat restoration.

 

[Diving Dubai]

Isn't there also dry ice and talcum powder blasting methods?

My understanding - Talc blasting is really ground glass.

similar to salt for coarse and talc for fine.

Yes done dry ice too. Issues though with localised thermal shocking on some substrates

You'd be surprised what gets used though

*OT* Once, in act of desperation we certified domestic oven cleaner for use in teh field on certain aircraft components.

Manufacturer couldn't supply - so on mass cleared out every supermarket in the area of all stock

Some managers were reticent - until you waved the credit card. Although one said - "I have another delivery tomorrow do you want that too"

Yes I do!