Stripping & painting AL Tanks

[FredT]

If any is involved it's way thin and not very effective.

If hand sanding follow up with a phosphoric acid rinse. Kano Labs Exrust is a good pretreatment product. This will remove all poorly adhering zinc and any residual rust.

After a thorough inspection for pits the tank can be recoated with ZRC. Do clean and refinish the entire tank exterior. The OMS Imron doesn't seem to be holding up well.

Rework cost if you DIY should be about $60 for the first tank, less for later tanks as the materials can mostly be reused. It's still cheaper than going for new bottles.

FT

 

[GP]

Thanks for the info Fred. Where can I obtain the products you speak of? Also, if I remove all of the rust and repaint the whole tank, is it necessary for me to strip the "entire" tank even in the areas that show no signs of corrosion or is just repainting sufficient enough?

 

[JDostal]

Yeah...I'd have to say go this route. I know you said you were looking to *cheaply* paint tanks...but it's not going to be very cheap no matter how you do it.

My diving friends were telling me the story of this idjit that spent a LOT of money to paint his tanks the color of his truck...and then screamed and yelled every time they were moved because he didn't want them to get scratched!!!

Tanks will get beat up...straight aluminum w/ a sticker will last much longer....and be dirt cheap.

Dee once bubbled...
They won't be pretty very long. Chemically strip the old paint off and to customize them, put a nice club sticker on them.

• You won't be looking at chipped paint again in a few months.
• With no paint, you can always tell the condition of your tank.
• The most you'll have to do to keep them looking nice is replace the club stickers.
• It's lots cheaper and less work!

 

[FredT]

GP once bubbled...
Thanks for the info Fred. Where can I obtain the products you speak of? Also, if I remove all of the rust and repaint the whole tank, is it necessary for me to strip the "entire" tank even in the areas that show no signs of corrosion or is just repainting sufficient enough?

As far as doing the entire tank, I would. Then again I have been accused of being real anal about some things. If the "factory" finish fails in one place, what will prevent it failing in another area. If the process has failed, fix the process, don't patch it and have to do it over again later. A double coat of ZRC is the next best thing to hot dip, and it won't void the DOT/TC roll mark.

For ZRC check the website for a dealer near you. It ain't cheap, but it's worth it.

http://www.zrcworldwide.com/

For Exrust contact Kano Labs at: http://www.kanolabs.com/ or 800-311-3374

Check the industrial supply houses in your area for bagged abrasive media and shell media. Ground corn cob can be had at most feed stores as animal bedding. It takes a bunch of cob unless you have a recirculating blast cabinet and you can upsize the suction tube. Walnut, almond, peach pits, or pecan shells would be a better bet if you are reusing media. What type shell material you can find locally will vary by region. All shell media of similar size will work about the same provided particle size is similar.

BTW Caustic strippers CAN be used on a steel tank. Don't get them near an Aluminum tank though. The reaction of aluminum with a caustic stripper is quite impressive.

FT

 

[GP]

Thanks again Fred. I ordered some Exrust today and I plan to get some ZRC as well. Since I live in an apartment and don't have access to a nice workshop with an air compressor for blasting and what not I'll have to use stripper to get the paint off the tank. After reading some past posts it sounds like it's going to be a crappy job but in the end it should be worth it. Now with the ZRC would it be ok to apply the two coats with a brush or mini roller or should it only be sprayed on? Again, I don't have an air compressor and spraying equipment so I pretty much need to do the brushing method but I'm wondering if that is an adequate way to apply the ZRC to a "tank" before I go ahead with this project.

 

[FredT]

ZRC is good for brush on, but reportedly it does come in an aerosol now for field touch-up. I haven't used the aerosol yet. If brushing you may want to do several thin coats instead of two thick ones to ensure you don't have any holidays in the coating.

Be sure to mix the stuff thoroughly and often whichever method you use. The zinc powder it contains wants to drop out of suspension pretty quickly.

FT

 

[Bob3]

Can't recall the name, but we used some aerosol "cold galvanizing" spray back when I used to be a pipefitter.
Maybe if I think for a while... [darn CRS]

Paint stripper suitable for aircraft use [safe for aluminum] is available from the average auto parts store, after that a satin finish can be applied to Al tanks by hand with a Scotch scuff pad.

If you just HAVE to paint the sucker, an immediate application of zinc chromate primer is in order.
RustOleum makes a nice high gloss "appliance white" that we used to use on rockets. Sticks tight & EZ to touch up.
:mean:

 

[thethumper]

FredT once bubbled...

BTW Caustic strippers CAN be used on a steel tank. Don't get them near an Aluminum tank though. The reaction of aluminum with a caustic stripper is quite impressive.

FT

Hey Fred,

Does this include Naval Jelly?

 

[FredT]

thethumper once bubbled...


Hey Fred,

Does this include Naval Jelly?

Naval jelly is a jel form of phosphoric acid. Acid eats aluminum, but nowhere near as fast as a caustic like lye.

Acid = high in H+ ions
Caustic = high in HO- ions

Both are bad for light metals, but caustic is orders of magitudes worse. If you remember dry Drano drain cleaner the active ingredients were dry lye and aluminum chips. Just add water and stand back.

FT

 

[Bob3]

Phosphoric acid, ain't that the stuff in Coca Cola?
Coke makes a good "liquid wrench" alternative for rusty bolts.
Meat tenderizer, too.