8 inch cylinders - read if you've dove one

[liberato]

Cold galvanization is just basically a high zinc paint primer. It won't last long on its own, so it needs to be top coated. You wouldn't paint a hot galvanized tank.

 

[FredT]

Ahh, great info, thanks.

Why are tanks such as Fabers painted over the zinc, then? Just because it looks better, even though it ultimately makes the tank more susceptible to rust?

Two options.

1. Marketing trumps sound design, or
2. Engineer is not properly trained in marine corrosion (most likely).

Never underestimate the ignorance of landlocked engineers when they are designing marine installations. All engineers intuitivly understand the truism that "Mother Nature is a *****!"

Most land based engineers have no clue however of the much greater truth that "Mother Ocean is a HUNGRY ***** who WILL be fed!" until of course she has taken a few large bites out of their arse!

FT

 

[jonnythan]

Great info. Thanks again Fred.

 

[liberato]

...per PST, they are not 7.25 but 7.3...

Not according to PST's spec sheet.

 

[FredT]

Cold galvanization is just basically a high zinc paint primer. It won't last long on its own, so it needs to be top coated. You wouldn't paint a hot galvanized tank.

A true "Cold Galvinizing" has a continuous phase of zinc and functions exactly as a hot dip galvanizing. The rub is that outside of ZRC and a couple other "premium" coatings most products sold as a "Cold Galvanize" are simply zinc pigmented paints with a binding resin as the continuous phase. These lesser coatings are simply fancy barrier coats, and depend on multiple coats to close holidays.

Properly applied ZRC coatings have lasted over 20 years at sea without a topcoat.

FT

 

[jonnythan]

I'm mucho amused with the use of the word 'holiday' in this sense, just in case anyone was wondering.

 

[liberato]

...The rub is that outside of ZRC and a couple other "premium" coatings most products sold as a "Cold Galvanize" are simply zinc pigmented paints...

Would it be worthwhile to have a can of it around for ding touchups on a PST hot galvanized tank? This diver painted his whole tank.

 

[FredT]

Would it be worthwhile to have a can of it around for ding touchups on a PST hot galvanized tank? This diver painted his whole tank.

Like most chemical blend products ZRC has a shelf life, although if I remember correctly it is a considerable period. Small dings on a hot galv tank will self heal. Larger dings (hydro stamps etc) should get a ZRC topcoat. That said I'd find a relatively local stocking supplier and simply order a small can when needed so it's "fresh".

FT

 

[Fireboat57]

I'm mucho amused with the use of the word 'holiday' in this sense, just in case anyone was wondering.

"HOLIDAY
Naval name for a gap, such as an area on a ship's side left unpainted, or a
space on a clothes line between pieces of linen hung out to dry."

I think this usage has been around since the first petty officer on a naval ship found a spot that a young seaman missed while painting. I know that my first experience was when the 2nd Class Bos'n politely inquired of me "What the hell were you doing, taking a @#$^#$ holiday?". He then proceeded to explain the fine art of chipping and painting to me. What a guy...

Do a search for "Navy Slang" or "Jackspeak" there are a lot of pretty strange words that make for some light reading.

Toby