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#4948
Powder Coating Steel Tanks
timengle - 9/13/2009 4:40 PM
Category: Equipment
Replies: 7



I have recently purchased 2 used steel tanks, and I would like to make them look a little nicer. Does anyone know if the powder coating process will affect the integrity of the tank? Any thoughts or opinions would be greatly appreciated.


Tim
#3979
DalelynnSims - 9/14/2009 6:50 AM
As a tank inspector let me add a bit on this subject. Powder coatings can be applied in a couple ways and there are a couple ways in which the metal is prepared as well; one method requiring a chemical etching and the other using sand or glass bead blasting. These are used to prep the surface to hold the new coating. With scuba tanks it has always been advised that you not alter the metal in any way including sanding. After the cleaning and applying the power coating the process requires powders to cure at about 400°F. Again something that is not advisable for scuba tanks. Lets say you do get this done there is yet another issue. When a tank is inspected if something is felt under the paint, yep that salt water will find its way in then it will have to be stripped to inspect. Tank makers go to great extremes to ensure that their products will last you for decades with proper care. It is my opinion that if this is done you put yourself and others at risk. I for one would not fill it knowing what was done. My .02cf worth
#1971
nauidiver - 9/14/2009 6:43 PM
From DalelynnSims: As a tank inspector let me add a bit on this subject. Powder coatings can be applied in a couple ways and there are a couple ways in which the metal is prepared as well; one method requiring a chemical etching and the other using sand or glass bead blasting. These are used to prep the surface to hold the new coating. With scuba tanks it has always been advised that you not alter the metal in any way including sanding. After the cleaning and applying the power coating the process requires powders to cure at about 400°F. Again something that is not advisable for scuba tanks. Lets say you do get this done there is yet another issue. When a tank is inspected if something is felt under the paint, yep that salt water will find its way in then it will have to be stripped to inspect. Tank makers go to great extremes to ensure that their products will last you for decades with proper care. It is my opinion that if this is done you put yourself and others at risk. I for one would not fill it knowing what was done. My .02cf worth

Sounds like she knows her stuff to me!
I think I’d let them be man... I would just wrap a skin around them if there to bad... I got some for my wifes two new tanks from leisure pro & they worked well!

- Dale
#5471
DiveBuddyChgo - 9/15/2009 3:38 PM
I would just use them... And not worry about getting them beat up... I would if anything brush them out and clear coat... But personally I don’t care what my tanks look like... As long as they get a lot of use and pass the inspections..
#1379
Fritz - 9/16/2009 7:12 PM
Dalelynn,
How is it that the tank manufacturers can paint or coat the tanks in the first place?
I have a dive buddy that has painted his tanks with Imron paint. They were painted prior to hydro testing.
I have seen how SCUBA tanks are made, and they are sanded by a belt sander at the end of the manufacturing process. This sanding is done in a cross plane manner as well, leaving fine sanding groves to begin a crack from expansion and contraction.
I feel like this may be another one of those liability things that nobody wants to cross a line by saying, "Yes you can".
#5799
csemenko - 9/17/2009 11:52 AM


From Fritz: Dalelynn,
How is it that the tank manufacturers can paint or coat the tanks in the first place?
I have a dive buddy that has painted his tanks with Imron paint. They were painted prior to hydro testing.
I have seen how SCUBA tanks are made, and they are sanded by a belt sander at the end of the manufacturing process. This sanding is done in a cross plane manner as well, leaving fine sanding groves to begin a crack from expansion and contraction.
I feel like this may be another one of those liability things that nobody wants to cross a line by saying, "Yes you can".




Okay, I’m a tank inspector too and I can tell you right now if you cover up the markings on the tank where they can’t be read your tank will fail my visual inspection. I also doubt you find anyone to fill it with the markings covered. Make sure you can read all the data (SN, Hydro, etc).


The tanks are sanded and painted at the factory...if you spray paint them yourself no issue; however, like mentioned before don’t "bake" the paint on. Any heat treatment (including running a belt sander on it yourself) can ruin your tank and if there is any evidence of baking it you will fail visual as well. This is a safety issue...heating metal causes it to become brittle...brittle metal breaks...tanks are exposed to high pressure...when they break it is bad for the person filling it. It isn’t a liability issue it is a "I don’t want to die or kill someone else" issue.


Whatever you do, don’t paint or coat the inside of your tank. This deadlines it too. The standards are there to prevent accidents, injuries, death, and loss of property.


If you want to learn about the "why" of it and not listen to speculation take the PSI course and the Gas Blender course so you can learn about the entire process and safety. This also removes the "it is a liability" mentality.


On the "it is a liability issue" you will also learn how you might kill a person filling your tanks if they are doing a partial pressure blend on your Nitrox tank and you’ve been filling it with air on your compressor after it was O2 cleaned and fail to mention it because "they just tell me it has to be O2 clean because it is a liability issue or they just want more money."


It is also a safety issue with painting a tank. Just know what you are doing and how to do it safely before doing it. Good luck.
#8636
ScubaSteve63 - 9/22/2009 7:13 PM
why paint? if your tanks are the same diameter as aluminum 80s you can just get a skin to wrap it.
#7352
UWnewbee - 9/23/2009 12:36 AM
From ScubaSteve63: why paint? if your tanks are the same diameter a aluminum 80s you can just get a skin to wrap it.
Amen Steve,,, 1 rule of ethics, if it works,,, LEAVE it alone,, if you prefer to have your tanks match your car or truck, drive em both off the pier. As a welder for many years and being a harley rider and builder ive seen my share of powder coatings that were supposed to be bullet proof, hit in the wrong spot or the wrong beginning steps to apply it, it chips with a hard enough hit or sharp impact point!also painting areas with sharp outlines such as when the inspector stamps the hydro and gives it a quick splash to deter any outter evironmensts is okay,, but any sharp edge will not hold paint and will be easilly chipped thats why as fabricating metals we bevel the edges to hold the paint and deture the thin coat,,, but grinding the sharp edeges would be time consumming from the hydro stamp, so there fore,,,,,,,,, if it works Leave it alone and buy a skin or mesh cover!!