Plastic coated steel 72's

[Dryglove]

Just expect to need to recoat the cold-galv fairly frequently, because you will need to. I'm not going to topcoat mine, as I want easy access to the cold galv for touch-up purposes.

I dont know what you consider to be often but mine have held up great for 6 mos with no need for touch up. The other day i ran across a guy at the dive site with a steel 72 that he coated with ZRC 2-3 years ago with no need for touch up. Of course a lot has to do with surface preparation and how rough you treat your tanks. I also agree there is no need to paint your tanks over the top of the galvanizing compound.

 

[FredT]

lal7176 once bubbled...
I dont know what you consider to be often but mine have held up great for 6 mos with no need for touch up. The other day i ran across a guy at the dive site with a steel 72 that he coated with ZRC 2-3 years ago with no need for touch up. Of course a lot has to do with surface preparation and how rough you treat your tanks. I also agree there is no need to paint your tanks over the top of the galvanizing compound.

A good ZRC coating will hold for 10-20 years or more if not top coated, a bit less if you top coat it. Other "cold galvanizing" mixes seem to be a one or 2 year coating if the tanks see salt water regularly.

Good source for phosphoric acid is Exrust available directly from Kano Labs. This stuff is also a good tumble helper if diluted about 3-5 to 1 with water.

http://www.kanolabs.com/

 

[Genesis]

sells an ospho dip that has a surfactant in it, which helps it get into and behind corrosion a LOT and speeds its action. Its green in color - looks like someone put some Palmolive in there in terms of color

I keep some of it around as I use it for dipping my boat heat exchanger cores, which build up all kinds of crud on them. It strips that stuff right off and leaves the base metal alone.

I'll see how the ZRC stuff holds up.

 

[captain]

I have found that brush painting tanks with ZRC provides a more durable and thicker coating than using the spray can version.

Captain

 

[ew1usnr]

captain once bubbled...
I have found that brush painting tanks with ZRC provides a more durable and thicker coating than using the spray can version.

I wondered about that. I'll get a quart can and brush it on. Thanks.

 

[Dryglove]

ew1usnr once bubbled...


I wondered about that. I'll get a quart can and brush it on. Thanks.

I was told that the spray cans are for more of a touch up plus they are expensive compared to buying it in a quart can. I applied mine with a roller to get a nice even finish. They are currently on ebay if you want to see a picture of them http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3637176210&category=16057&rd=1 I went to the dive shop the other day and got weak in the knees and bought a set of E7 100 pst double tanks. Now i have more air than i know what to do with and debt to go with it. I was getting 2 decent dives with the 72's and am getting 3 decent dives with the E7's.

 

[ew1usnr]

lal7176 once bubbled...
I applied mine with a roller to get a nice even finish.

That is a good looking set of tanks. The ZRC provides a decent finish.

 

[Genesis]

and like them a lot.

They're pretty heavy though for open ocean diving. I get 2-3 dives off them as well, which is nice. The double 72s are attractive simply 'cause they should still give me the two dives, but be about 15lbs lighter "all up" and a bit more negative (which in a dry suit is great - less lead to carry around - in a wetsuit its not as wonderful, but they should still be easily swimmable.)

 

[ew1usnr]

Oh, wow. You guys passed up the opportunity to pack 300 cubic feet on your backs. It looks like they would start out at over 21-pounds negative. I guess that that is a saltwater measure. They would be even heavier in fresh. With something like this having a backup BC could be a life saver. I have a pair of aluminum 100's that work pretty well.

http://www.fillexpress.com/library/pstcylinders.shtml

 

[Dryglove]

Genesis once bubbled...
and like them a lot.

They're pretty heavy though for open ocean diving. I get 2-3 dives off them as well, which is nice. The double 72s are attractive simply 'cause they should still give me the two dives, but be about 15lbs lighter "all up" and a bit more negative (which in a dry suit is great - less lead to carry around - in a wetsuit its not as wonderful, but they should still be easily swimmable.)

I was originally looking at the PST LP80's as PST has them on sale right now. I compared them to the 100's and wasnt much difference in size except for the price tag. I just decided to go with the 100's as i am hopefully gonna try to take some more training next year and decided the extra air couldnt hurt. This was a bad year for training for me as i didnt get to take any of the classes like i wanted such as the fundies class, advanced nitrox, or deco procedures. Hopefully next year things will go better and can use these big tanks for something besides recreational diving.

Here is the weight difference between the 72's and 100's

steel 72's w/600 psi of 25% = 73lbs

E7 pst 100's w/2150 psi of 31% = 87lbs