Black residue

[C_C]

C_C

 

[wb416]

Uncle Pug once bubbled...
Nice logo C_C... looks just like the one on my truck... (thanks )

me startin' to tink I'm no longer #1 customer.... egads!


Patiently awaiting my sticker...
wb

 

[rmediver2002]

As far as I know the production cycle of Faber cylinders does not include any kind of coating the interior of the cylinder after it is shotblasted.

The Faber cylinders do receive an internal coating but it is not black in appearance, after shot blasting the steel receives a phosphatized coating that seals the surface of the steel with a thin, clear, protective layer.


http://www.divefaber.com/

http://www.aquasafaris.com/store/secondarypages/Tanks/steelcylinders.html

http://www.abysmal.com/pages/features-cylinders.html

Jeff Lane

 

[pescador775]

I have three Faber cylinders in my locker which have black (parkerized) phosphate internal finish. These are new, 'old stock', manufactured in 1999. Faber used to tout this as a 'food grade' oxide coating.

 

[pescador775]

rmediver, I can find nothing in any of the references to a 'clear coating', only 'exclusive phosphatized coating'. I seems likely that Faber has been using a zinc phosphate. This is the most rust resistant of the oxide coatings and is gray to black in color. However, I'm not certain of the toxicity, if any. Some zinc compounds contained in paints are toxic. If they have a 'clear' coating I would like to know what it is, just out of curiosity.

 

[C_C]

I have known of the use of "food grade oxidation", but was not familiar with any sort of "Parkerization".

My understanding of a Parkerized surface is that it requires a light coating of oil to maintain a corrosive protection.

Thanks again,

C_C

 

[rmediver2002]

Pescador:

The clear coat mentioned in my previous post is a reference to the color of the finish not the type of application.

My cylinders were made in 2000; they are the SCUBA PRO 95 cf made by Faber. I have 30 units all from the same batch; the interior surface remains blemish free retaining the color of freshly bead blasted steel.

I would agree with your assumption that the current mixture is most likely a light zinc phosphating compound. I have not been able to find any specific composition information for the current coating but the light coloring inside my tanks would be indicative of a light zinc compound.

The description of the surface inside your tanks (dark grey to black) would seem to indicate some experimentation with other types of phosphate mixtures (like Parkerized) or variations in levels of zinc, iron, or manganese.

Did something from your tanks mention the trade name Parkerize specifically?

Again this is an assumption on my part but it would seem to make sense to check the practicality of the system with products off the shelf or currently produced before having an “exclusive phosphatized coating” developed. This is most likely the case.

Anyone else with Faber tanks have any additional interior surface descriptions?

C_C:

The dry environment within the cylinder lends itself to preservation of the material without the application of additional coastings such as oil, paint, or wax. Light zinc coated surfaces are designed to withstand from 1 to 2 hours of salt spray test. I am sure it would be resonable to assume direct exposure to salt water would within a short time defeat any type of preventative coating inside the tank.


Very interesting thread to me...


Jeff

 

[pescador775]

rmediver, I should have said 'looks like parkerized'. The interior of my tanks resembles the finish on old KBAR military knives, a black phosphate called by that trade name. BTW, the description of Faber's interior finish has definitely changed. Formerly, they were advertised as 'food grade oxide', now 'exclusive phosphatized'.

I don't know if that means anything radical has changed other than color. Certainly, the appearance has definitely changed on the SP interiors from what I'm hearing from you. Most manufacturers consider the typical dark appearance of conversion coatings desirable since flaws can easily be spotted, like prior to over painting. Scubapro, et al may have advised that they feel that tank interior rust can be more easily detected if the finish is light or clear. Big users can affect specifications from the OEM. I seem to remember that a true flat black coating requires something called a black pre-dip. I'm also thinking that a clear effect can be created by omitting this step. Just speculating.

I agree, the subject is interesting.

Pesky

 

[rmediver2002]

Hello everyone,

I decided to contact faber and ask about the interior coating and this was the reply:

"our diving cylinders are internally shot
blasted and Phosphatized (washed with amorphous iron phosphates in order to
de-grease the internal surface).

Yours faithfully,

Faber Industrie Spa"



I also mentioned in the message to them that of the thirty tanks in Nitrox service since 2000 not one has any evidence of flashing or corrosion at all...

Very impressive, I am anxious to see the results after ten years...


Jeff

 

[pescador775]

OK, thanks. They're using something similar to 'Superphos'.
http://www.milanco.com/convenient/iron.htm