Issues stripping paint from Al40s

[SparticleBrane]

Awhile ago I ordered (4) Luxfer Al40s in the brushed no-coat finish. Due to a shipping/distributor error I ended up with these cylinders...in neon yellow. :shocked2: I really, really, really hate neon yellow cylinders. But, returning and shipping these back and forth would be a huge hassle, so the seller and I have come up with a deal but that's another story.


Thus I'm trying to get rid of this nasty paint job. These are brand new and have never been used.

I saw a thread awhile back about stripping the paint from aluminum cylinders, so I read that plus Luxfer's official recommendation.

The thread recommended using aircraft paint stripper so I went out and bought a can of that. I sprayed it all over the four cylinders, and while I could see the paint bubble a little it didn't bubble as much as some photos shown in the previous thread.

After doing some scraping it still didn't seem to be doing much so I went out and bought some "Zip-Strip", which is Luxfer's official recommendation for stripping paint off their cylinders. It didn't have much impact either.


Am I doing something wrong?! This neon yellow paint has to go...I just can't deal with it. I am trying to emulate this but obviously it isn't working out so well. Let me also say I've spent enough money on the aircraft paint stripper ($8/can) and the Zip-Strip ($13/can) as it is so I'm trying not to spend any more if I can. I probably still have 2/3rd's of a can of Zip-Strip left but I'm all out of the Aircraft stuff.


A few shots---

This is about as bubbly as the surface of any of the cylinders got:

This was before using the Zip-Strip, which had little effect. I actually have several areas on two of the cylinders without any trace of paint, due to me peeling it off rather than having it bubble up and fall off, or scraping it off. Pretty annoying.

 

[porbeagle]

This question has been adressed many times before with lots of opinions.
I have used soda blasting which works great,but may cost unless you
know someone who can help you out. So called "Dollar Stores" which sell
cheap tools usually have sandblasters which can be used with a light
compressor,They run about $20. You can use walnut shells as a medium
also.Don't use sand it's hard on AL. Or search out older threads on SB,
But be prepared to wire brush or sand till it hurts.
Luck, PORBEAGLE

 

[halocline]

Just get regular paint stripper, the paste stuff that has methylene chloride. (I think) Brush it on, leave it. Repeat. Eventually you'll get the paint off. I took lacquer off my AL80. It took several applications, and no way was that stuff as tenacious as original paint on a new cylinder. There were also some scratches from the putty knife I used. I sanded those out with 320 silicone carbide paper on a palm sander. It looks -okay- but if I were doing it over I'd use some sort of light sand/soda/shells/whatever blasting.

 

[SparticleBrane]

Apparently the Zip-Strip stuff has methyl chloride in it.

 

[Rick Christ]

January 16, 2007

Paint removal and repainting of Luxfer all-metal and composite cylinders made from 6061 aluminum alloy (L6XŽ®)1

1. Preparation

a) All-metal Luxfer 6061 aluminum alloy (L6XŽ®) cylinders͵o remove paint from an all-metal cylinder and prepare the surface for repainting, blast with plastic, glass or other soft media just long enough to remove most of the old paint. Do not blast with sand, steel, grit or aluminum oxide media, which are too abrasive. Heavy or improper blasting with hard or overly abrasive media removes metal as well as paint from the cylinder, which can thin the cylinder wall and make the cylinder unsafe to fill or use. Improper blasting also obliterates stamped markings and damages the outer surface of the cylinder.

Never use corrosive, caustic or acidic paint strippers or solvents to remove paint. Never use burning or torching techniques. Do not use knives or other sharp instruments to remove labels.

Once paint has been removed, use a neutral, mild, water-based detergent to wash the cylinder. Rinse the cylinder well and thoroughly dry it at a metal temperature not exceeding 160 degrees F (70 degrees C). Carefully inspect the cylinder surface for damage and corrosion in accordance with all applicable regulations. If the cylinder passes the inspection, it is ready for repainting.

b) Composite cylindersͥo not attempt to remove intact old paint from composite cylinders by blasting or any other means that may damage the cylinder exterior. Lightly rub the surface with fine-grit emery paper to prepare it for repainting. If the surface is dirty, clean it with a neutral, mild, water-based detergent, then rinse it well and dry it thoroughly.

Never use corrosive, caustic or acidic paint strippers or solvents to remove paint or to clean composite cylinders. Never use burning or torching techniques. Do not use knives or other sharp instruments to remove labels.

Once the outer surface of the cylinder is clean, inspect it for damage in accordance with all applicable regulations. If the cylinder passes the inspection, it is ready for repainting.

c) All cylinder typesͥo not use the above preparatory processes on the internal surface and thread area of any Luxfer cylinder. Different processes (not covered by this document) should be used to clean threads and internal surfaces.

While preparing a cylinder exterior for painting, take care not to damage the valve connection area or cylinder threads. Do not allow any process materials (e.g., cleaning agents, blast media, grit, etc.) to contaminate the threads and inside of the cylinder.

2. Painting

a) All-metal Luxfer 6061 aluminum alloy (L6XŽ®) cylindersÍ¥o not use acidic or caustic paints that may damage the cylinder exterior. You may use any neutral, air-drying or aliphatic, water-based or solvent-based liquid paint that is compatible with aluminum. You may also use neutral, aluminum-compatible powder coatings as long as curing temperatures and exposure times do not exceed those recommended by Luxfer. Please note that different aluminum alloys have different maximum-temperature specifications; for example, for Luxfer 6061-alloy (L6XŽ®) cylinders, the maximum metal temperature must not exceed 350 degrees F (175 degrees C). Exposure times at various temperatures vary according to alloy. Please contact Luxfer for time/temperature information about the particular cylinder and alloy that you intend to repaint using powder coatings. Cylinders subjected to temperatures and exposure times exceeding Luxfer recommendations or heated to unknown temperatures must pass hydrostatic tests before being filled or used.

b) Composite cylindersͶse flame-retardant, air-drying or aliphatic, water-based or solvent-based epoxy or polyurethane liquid paints on Luxfer composite cylinders. Do not heat cylinders to speed up curing or drying of paint. Do not use powder coatings or other coatings that must be heated or baked. Never expose composite cylinders to heat exceeding 180 degrees F (82 degrees C).

Do not paint over cylinder labels. Mask labels before painting and make sure that they remain legible. (Note: Color coding cylinders to identify gas contents or usage does not eliminate the regulatory requirement for legible, properly configured labels.)

c) All cylinder typesͥo not allow paint to contaminate the threads, valve connection area or internal surface of any Luxfer cylinder.

1Luxfer markets its proprietary version of 6061 aluminum alloy under the registered trade name L6X

Luxfer: Technical Bulletins: August 9, 2006

 

[dumpsterDiver]

buy a can of DIR black spray paint from Home Depot, hang them from the garage door on string and be done in 20 minutes. You might scuff them first with very fine paper.

Repeat every other dive season.

 

[Tamas]

Interesting that you are not getting more seperation....are these new tanks or used? Possible they have been powder coated? Is there a vinyl coating on the tank? Test by scraping it first with a knife.

The stuff I have used with good results, is this

on several occasions - got it from NAPA for $5 a can, usually takes 1.5 cans to do a AL80, and as you saw in my pics, it bubbles quite well after 10 minutes.

 

[SparticleBrane]

Hmm.....not quite the response I was expecting.

So far I've had people respond who haven't read what I actually posted, who gave me tongue-in-cheek answers, and who quoted something from the Luxfer website that doesn't apply to me.

To porbeagle:
If you read what I posted carefully, it should be apparent I've already searched for threads on this topic, as I reference one. Thank you for the info on sandblasting, although that won't be happening to these cylinders.

Rick Christ:
While I appreciate the posted of Luxfer doctrine (in multiple threads, now....) if you look closer at the Luxfer website you can see they recommend a paint stripper here. I was actually hoping for responses from people who have stripped the paint from cylinders before...

dumpsterdiver:
I should have expected such an answer from you. :mooner: Note that I didn't mention repainting the cylinders at all -- I just want to remove the paint.



tamas -- These cylinders were manufactured in March of 2008 but haven't been used; they are brand new. Do you remember what brand of paint stripper you used? How large was one can? Aerosol? Paint on? Sorry for so many questions. The first thing I tried was an aerosol, with the second a gel that I had to paint on.

Apparently this Zip-Strip stuff is supposed to work quite well, but so far it's having sub-par results and I am disappointed. Or maybe Luxfer just paints their cylinders with nuclear blast-resistant paint.

 

[cwkline]

Sparticle,
My instructor/mentor dive buddy has done this to many of his cylinders. He is currently out of town, but I will send a message anyway and see if he responds. Sorry I couldn't be of immediate assistance, but I really didn't pay much attention when he told me how he stripped the paint.
I will let you know when I get a response.
Charlie

 

[SparticleBrane]

Sparticle,
My instructor/mentor dive buddy has done this to many of his cylinders. He is currently out of town, but I will send a message anyway and see if he responds. Sorry I couldn't be of immediate assistance, but I really didn't pay much attention when he told me how he stripped the paint.
I will let you know when I get a response.
Charlie

I appreciate you doing this. Please let me know what he says!

My main reason for posting this thread is that I believe I am doing what the other guys did in the previous thread (or something close to it), I'm using the same chemical strippers recommended by both the people in the thread AND by Luxfer, and I'm having crappy results.


Just bugs me that I'm doing what other people have done with success in the past, and it isn't quite working as well as I'd hoped. Jut frustrating, more than anything. :shocked2: