diver30
Guest
can anyone help i have 10 ltr tank and i want to paint it but i dont no which paint to use or how to remove the paint on it so please help
diver30
diver30
Sanding paintin a tank
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FredT
Guest
I'll start off by assuming you have a 10L steel tank. I'll also assume that your tanks are similar to what we use in the states. If either of these are off base then all bets are off.
Almost all steel tanks here are galvanized with a zinc coating before painting. The best thing you can do is be extra careful not to damage this galvanizing. This goal provides you with a list of DO NOTs.
1. Do not use mechanical abrasives harder than zinc to remove the paint.
2. Do not wire brush the tank to remove the paint. The wire ends will cut away the zinc, and power brushing may spot overheat the tank.
3. Do not use acid strippers to remove the paint. The acid will dissolve the zinc, leaving a bare tank to rust under the new paint coat.
This so far limits you to caustic or solvent chemical stripping, or to abrasive blasting with nut shell media. Over here we use walnut or pecan shells for that type of cleaning. Over there it may be olive or almond shells that are most available. Another suitable, but expensive, cleaning method is to use carbon dioxide (dry ice)as the cleaning agent. This brings up another important point.
4. DO NOT EVER USE CAUSTIC STRIPPERS ON ALUMINUM TANKS! The chemical reaction between the tank and chemical will be impressive, and WILL harm the tank!
The next step is to repair any spot damage to the galvanizing coating. This can best be done with a "cold galvanizing" compound. It will go on like a paint, but dry to a coating that is over 90% metallic zinc. ZRC is the best product of this type over here, and is suitably priced. It may not be available over there but a similar compound should be.
Once the tank exterior is in good shape and regalvanized it can be top coated. Almost any paint will work, but be sure you can get it off for the next repair. Some epoxy and urethane based coatings will last quite a while, but eventually any topcoat will have to be removed for inspection purposes. I prefer my tanks to have a bare galvanized finish to make them easier to service and inspect.
FT
Almost all steel tanks here are galvanized with a zinc coating before painting. The best thing you can do is be extra careful not to damage this galvanizing. This goal provides you with a list of DO NOTs.
1. Do not use mechanical abrasives harder than zinc to remove the paint.
2. Do not wire brush the tank to remove the paint. The wire ends will cut away the zinc, and power brushing may spot overheat the tank.
3. Do not use acid strippers to remove the paint. The acid will dissolve the zinc, leaving a bare tank to rust under the new paint coat.
This so far limits you to caustic or solvent chemical stripping, or to abrasive blasting with nut shell media. Over here we use walnut or pecan shells for that type of cleaning. Over there it may be olive or almond shells that are most available. Another suitable, but expensive, cleaning method is to use carbon dioxide (dry ice)as the cleaning agent. This brings up another important point.
4. DO NOT EVER USE CAUSTIC STRIPPERS ON ALUMINUM TANKS! The chemical reaction between the tank and chemical will be impressive, and WILL harm the tank!
The next step is to repair any spot damage to the galvanizing coating. This can best be done with a "cold galvanizing" compound. It will go on like a paint, but dry to a coating that is over 90% metallic zinc. ZRC is the best product of this type over here, and is suitably priced. It may not be available over there but a similar compound should be.
Once the tank exterior is in good shape and regalvanized it can be top coated. Almost any paint will work, but be sure you can get it off for the next repair. Some epoxy and urethane based coatings will last quite a while, but eventually any topcoat will have to be removed for inspection purposes. I prefer my tanks to have a bare galvanized finish to make them easier to service and inspect.
FT
As always, Mssr. Fred, your advice is excellent.
Glad to have you aboard!
~SubMariner~
Glad to have you aboard!
~SubMariner~
swedish diver
Registered
Hello diver30. If you'd like, you can repaint it - it's up to you, but concider first:
0) Are the tanks nice on the inside. Maybe the inside is rusty / damaged too. Then you will have to fix that first.
1) your LDS may not want to fill repainted tanks before they have been pressure tested, maybe not even then.
2) repainting it is - as Fred pointed out, pretty much work, and will cost you some if you do not already have the stuff.
3) If you're not doing it really professionally, the new paint will note last very long. In the factory, the paint is usualy "burnt" onto the tank in an oven. This method makes it more durable. However, do NOT do this yourself, as heat may cause tensions in the material of the tank. It could become a potential bomb.
I repainted a set of doubles two years ago - same method as Fred. It turned out great, but I wouldn't do it again. It's simply not worth the time (in my opinion), since 10 l tanks are pretty cheap.
Regards
/Kristian
0) Are the tanks nice on the inside. Maybe the inside is rusty / damaged too. Then you will have to fix that first.
1) your LDS may not want to fill repainted tanks before they have been pressure tested, maybe not even then.
2) repainting it is - as Fred pointed out, pretty much work, and will cost you some if you do not already have the stuff.
3) If you're not doing it really professionally, the new paint will note last very long. In the factory, the paint is usualy "burnt" onto the tank in an oven. This method makes it more durable. However, do NOT do this yourself, as heat may cause tensions in the material of the tank. It could become a potential bomb.
I repainted a set of doubles two years ago - same method as Fred. It turned out great, but I wouldn't do it again. It's simply not worth the time (in my opinion), since 10 l tanks are pretty cheap.
Regards
/Kristian
FredT
Guest
I forgot another Do Not.
Do not ever bake a finish onto an aluminum tank, or raise it's temperature much above water's boiling point!
Less than 50°C (~ 100°F) above boiling the aluminum will start to anneal, creating a HUGE burst hazard. Heat the tank if necessary by filling it with, or immersing it in, boiling water. Heat guns, torches, radiant heating, etc can easily raise the temperature locally much more than you want the tank to ever see way too quickly for you to react to save it. An Aluminum tank that just MAY have been exposed to too much heat should be scrapped. The cost in lives and body parts is just to high to "just try it" on an aluminum tank with any thermal exposure questions.
Annealing is a process that is dependent on both the temperature attained and the time it dwells at temperature. Below 300°F (148.9°C) the annealing time is long enough not to be a bother. Above 350°F (176.7°C) the aluminum will have reverted to T-0 temper, a state about 1/5 as strong as it was to start with. This causes the tank to burst at below it's rated working pressure. If I remember correctly the burst pressure is only about 1800 psi (124 bar) if the tank is fully annealed. Between 300 and 350° the condition of the metal will be somewhere in between.
FT
Do not ever bake a finish onto an aluminum tank, or raise it's temperature much above water's boiling point!
Less than 50°C (~ 100°F) above boiling the aluminum will start to anneal, creating a HUGE burst hazard. Heat the tank if necessary by filling it with, or immersing it in, boiling water. Heat guns, torches, radiant heating, etc can easily raise the temperature locally much more than you want the tank to ever see way too quickly for you to react to save it. An Aluminum tank that just MAY have been exposed to too much heat should be scrapped. The cost in lives and body parts is just to high to "just try it" on an aluminum tank with any thermal exposure questions.
Annealing is a process that is dependent on both the temperature attained and the time it dwells at temperature. Below 300°F (148.9°C) the annealing time is long enough not to be a bother. Above 350°F (176.7°C) the aluminum will have reverted to T-0 temper, a state about 1/5 as strong as it was to start with. This causes the tank to burst at below it's rated working pressure. If I remember correctly the burst pressure is only about 1800 psi (124 bar) if the tank is fully annealed. Between 300 and 350° the condition of the metal will be somewhere in between.
FT
Hello your local dive shop should be able get the work done for you the cost of blasting back to bare steel is about £ 8.00 and to prime and paint about £ 18.00 as has been stated the primer is a zinc coating bonded at the atomic level and acts as a sacrificial coating to the steel .A two part finish is applied over the top , you can as a non commercial user have any colour you wish it only needs a sticker saying what it is , Nitrox , air , trimix
If the coating is sound small chips can be touched up with zinc phosphate primer , if you want to paint the whole tank for cometic reasons apply an acylic primer and paint from Halfords
Alban
If the coating is sound small chips can be touched up with zinc phosphate primer , if you want to paint the whole tank for cometic reasons apply an acylic primer and paint from Halfords
Alban
A common problem over here is filling tanks to fast this will cause the dew point in the moisture to condensate as it cools causing internal rusting allways make sure the tank is immersed in water and filled slowly. Externally all tanks should have the boot removed and be immersed in fresh water after every dive ,
Take care of your tanks as you would all of your equipment
Alban
Take care of your tanks as you would all of your equipment
Alban
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