worthington vs pst

[lamont]

are you all saying that the PST looks better because it is shinier?

 

[rainman_02]

It won't after a few dives!

 

[rainman_02]

To say more:

I was planning on getting 2 PST E7-100s but I wound up going with the Worthington X7-100s because they appear to be much more reliable as far as delivering them. They are hot-dipped but not shiny, which just means there's no shine to get dull after some diving.

I think they look great and I love diving with them. After the holidays I plan on doubling them up.

 

[SDAnderson]

but I'm having difficulty with this statement. If any steel tank is kept pressurized to some degree with dry gas, and is refilled with whips that have no water (salt or fresh) droplets on the whips, internal rusting should not occur. If identical levels of moisture or water vapor are somehow introduced into two steel tanks, PST and Worthington, they should suffer roughly the same level of rusting over time. TTBOMK, the steel used for the tanks is basically the same.

OTOH, I've O2 cleaned steel tanks and they're all highly susceptible to flash rusting unless a rust inhibiter is used carefully during the cleaning process. I flash rusted one of my PST 130s and had to retumble it, and we'll see whats going on inside it during the next VIP. I suspect the same outcome would have occurred regardless of whether the tank was a PST or a Worthington.

Is there any data on this statement, or is this essentially an anecdote?

I don't know about the boats in Bill's area, but around here the ones with compressors on board are kind of scary. Filtration is minimal and dessication is a real problem, it's a nice service but I try not to take advantage of it. Hard to do on live-aboards, though.

A little bit of flash rust is an esthetic concern and not worth tumbling a tank to remove, though you can whip the tank and re-rinse it. If you have problems next VIP inside the tanks that were flashed, that happened separately. You can use the inhibitors to keep the flash down but I prefer a hot rinse followed with nitrogen to blow the tanks dry. The first little bit of nitrogen should be dribbled in to replace the air in the tank, then let it rip. N is cheap enough to use (not much more than the inhibitor) and produces a superior result in less time without any residue concerns. Just my .02.

 

[dl348]

It is my understanding that both the Faber and Worthington tanks are coated on the inside with iron phosphate which eliminates powder rust. The PST tanks do not have this. The outside of the Faber and Worthington tanks are zinc flame sprayed and then powder coated white. The PST tanks are hot dipped galvanized.

We have 2 Worthington LP 85s and 95s, they came with the Thermo Pro valve which can be used as either DIN or Yoke.

 

[PerroneFord]

I believe the coating only applied to the LP tanks (speaking of Worthington) before they began the hot dip on them. Now all their tanks are hot dipped. The older LP tanks are easily discerned because they are white on the outside like the old Fabers.

 

[oxyhacker]

I wouldn't get too excited about the phosphate coating - it's too light to have any significant long term benefits. If you are getting noticable water in the tanks, the phosphating is not going to protect them for long.

I've always wondered if the coating is really an intentional feature in itself or just a side effect of how Farber happens to be cleaning the tanks after forming. I asked a Farber rep at DEMA, and he agreed it was pretty much the latter.

It is my understanding that both the Faber and Worthington tanks are coated on the inside with iron phosphate which eliminates powder rust. The PST tanks do not have this.

 

[pescador775]

Iron phosphate is deposited or "reformed" on metal while in contact with a specially formulated cleaning and phosphating solution such as is available on the commercial market. Its purpose seems to be the same as the "Parkerized" finish sometimes seen on KBAR knives and firearms, to prevent rusting of steel or iron when exposed to tropical humidity. It works well for that purpose but will not stand up to immersion, especially to salt water. It would appear to be useful for use inside SCUBA tanks which are sometimes filled with humid air. Although commercial compressors often produce extremely dry air, the effect of compression is to raise the dew point of the remaining moisture which is gaseous, mixed with the air inside the tank. This may be apparent when examining NITROX tanks which have been stored in extremely cold conditions, eg a film of powder rust due to moisture condensation. Phosphate is inert and provides a thin physical barrier to this moisture.

 

[undrwater]

I picked up the Worthington HP 80 today. It was smaller than I expected, but it'll be nice during those beach dives with long hikes.

Still...rvrn th HP 100 was smaller and lighter than my LP 95...I think I may just trade it in!

 

[pescador775]

Wash tumble, dry, what a drag. I stopped doing that years ago. I used trichlorethane until it was banned from the planet (almost). The replacement (oxygen service) solvent is a bromine compound called ENSOLV. It's expensive, about $250 for five gallon drum. A quart can be poured into a SCUBA tank, sloshed around for a couple minutes and emptied into a container. The stuff that was poured out can be saved and used for general degreasing. As for the tank, dry with clean compressed air. Hang upside down for 24 hours to dissipate any slight odor, or insert valve and charge it, drain it, refill, and you are finished. No rust flash, no powder, no nothing.