Removing Paint from Aluminium Cans: A Scientific Approach

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In summary, Juba has invented a solar panel using used pop soda cans but needs to remove the paint on the cans in order to apply black chrome. He asks about the paint composition and the best chemical to remove it. Nicodemus suggests using Nitromors for metal surfaces, but warns about the disposal of toxic agents. Chemisttree recommends sanding or sandblasting the cans, but Juba wonders if electrolysis can also remove the label. Chemisttree explains the process of reverse anodizing but suggests sticking with sanding. Juba expresses gratitude for their help and mentions trying a product that did not work for removing the paint. He plans to contact a can producer for advice.
  • #1
Juba
9
0
Hi,

My name is Juba and I’ve invented a solar panel based on used pop soda cans.
But in order to apply the black chrome on the exposed aluminium, I need to remove the label (paint) on the cans.

What is the paint made of?
What is the best chemical to remove it?

I thank you in advance for any help you can provide.
 
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  • #2
Juba said:
Hi,

My name is Juba and I’ve invented a solar panel based on used pop soda cans.
But in order to apply the black chrome on the exposed aluminium, I need to remove the label (paint) on the cans.

What is the paint made of?
What is the best chemical to remove it?

I thank you in advance for any help you can provide.

That's easy, but not clean or quick. You can speed things up with heat, but that's an issue too, and using caustics presents its own challenges. If I had to pick one chemical, it would be Nitromors for metal surfaces. It's meant for DIY, and it definitely does the job, but you need to leave it on for a few minutes.

I'd add, this adds a dimension of washing and disposal of toxic agents to your production process, but you won't find a ready source of "blanks". As for what paint is used, I believe (for Coke at least) that it's an enamel applied with a kind of rotary silk-screen.
 
  • #3
Nicodemus said:
That's easy, but not clean or quick. You can speed things up with heat, but that's an issue too, and using caustics presents its own challenges. If I had to pick one chemical, it would be Nitromors for metal surfaces. It's meant for DIY, and it definitely does the job, but you need to leave it on for a few minutes.

I'd add, this adds a dimension of washing and disposal of toxic agents to your production process, but you won't find a ready source of "blanks". As for what paint is used, I believe (for Coke at least) that it's an enamel applied with a kind of rotary silk-screen.




Nicodemus,

Thank you very much. I really appreciate your effort to help me.
I am going to use thousands of cans in order to produce the panels. :-)

Since I am in France, I don’t know if I can find Nitromors. I’ve read about the product and it looks if it can do the trick.

Once again, thank you.
 
  • #4
You are going to need to sand the surface anyway. Why not sand it off? Two steps in one.

I assume that you are painting it black so it will absorb sunlight and heat up? Sandblasting preps the surface and provides the best finish anyway. I would think that you wouldn't want a shiny black can. Flat black is best for absorbing heat.
 
  • #5
chemisttree said:
You are going to need to sand the surface anyway. Why not sand it off? Two steps in one.

I assume that you are painting it black so it will absorb sunlight and heat up? Sandblasting preps the surface and provides the best finish anyway. I would think that you wouldn't want a shiny black can. Flat black is best for absorbing heat.

Sandblasting might be a little tough on such thin cans, but given the numbers and application you're right... sanding or etching, the surface will need to be prepared.

I'm not sure that it wouldn't be cheaper to buy sheet aluminum, sand THAT, and bam. Otherwise you sand carefully, heat to about 600 deg F, or use caustic, watch, sand, wash, etch, wash.

Juba, do you think there might be a French beverage company or branch that would be willing to tell you their paint forumula? If you have something specific, maybe you can make a specific, but very dilute bath and use time as your weapon. It might be that you can buy some industrial concentrations of your preferred solvent, and have a 6 stage system:

Solvent
Wash
Sand
Wash
Dry
Apply
 
  • #6
Hi Chemisttree,

You understood everything. :-)

Thanks a lot.

I will in effect consider sandblasting.

Do you thing electrolysis can peel of the printed label.

Sorry for asking. Maybe the question dumb, but if I don’t ask it, I will never learn.
 
  • #7
Nicodemus said:
Sandblasting might be a little tough on such thin cans, but given the numbers and application you're right... sanding or etching, the surface will need to be prepared.

I'm not sure that it wouldn't be cheaper to buy sheet aluminum, sand THAT, and bam. Otherwise you sand carefully, heat to about 600 deg F, or use caustic, watch, sand, wash, etch, wash.

Juba, do you think there might be a French beverage company or branch that would be willing to tell you their paint forumula? If you have something specific, maybe you can make a specific, but very dilute bath and use time as your weapon. It might be that you can buy some industrial concentrations of your preferred solvent, and have a 6 stage system:

Solvent
Wash
Sand
Wash
Dry
Apply

Guys,

I wish you were her!
I would at least buy you a beer (in a can).

I will actually try to contact one of the can producers here in southern France. Ball Packaging Europe has a plant down here.

Believe me, I appreciate your efforts and I hope to do able to do the same if you should need any help some day.

I’ve tried this product today (http://www.leboncoin.fr/bricolage_jardinage/173826508.htm?ca=6_s ).

No can do.

I smeared a can for more than an hour. It didn’t even “blink”.

Once again, thanks guys.
 
Last edited by a moderator:
  • #8
Juba said:
Hi Chemisttree,

You understood everything. :-)

Thanks a lot.

I will in effect consider sandblasting.

Do you thing electrolysis can peel of the printed label.

Sorry for asking. Maybe the question dumb, but if I don’t ask it, I will never learn.

You can definitely reverse anodizing, but you'd just be trading solvents for acid baths and electricity, and it's slower than the original process. If sanding sounds right for you (and you'd know!), I'd stick with that. You could even use a tumbler; if the can's deform, who cares, you could stick them in a pressure vessel and blow them right back up. Anything short of serious crushing shouldn't be an issue, and you could use a fine grit to protect the cans.
 
  • #9
Juba said:
Guys,

I wish you were her!
I would at least buy you a beer (in a can).

I will actually try to contact one of the can producers here in southern France. Ball Packaging Europe has a plant down here.

Believe me, I appreciate your efforts and I hope to do able to do the same if you should need any help some day.

Once again, thanks guys.

It's genuinely a pleasure, just let us know how this all works out, OK? It sounds like a good idea to me.
 
  • #10
I’ve tried this product today (http://www.leboncoin.fr/bricolage_jardinage/173826508.htm?ca=6_s ).
No can do.
I smeared a can for more than an hour. It didn’t even “blink”.
 
Last edited by a moderator:
  • #11
Nicodemus said:
It's genuinely a pleasure, just let us know how this all works out, OK? It sounds like a good idea to me.

I will keep you posted.
My success will be yours too.

Thanks
 
  • #12
You might consider blasting the can with dry bicarbonate. It is used to remove grafitti so it will be abrasive enough to cut the paint and mild enough to save the can and leave a water-soluble residue (bicarb!) on a matte finish can. No pesky silica to breathe in and no serious hazards with SiC.

The ink is crosslinked with UV light I believe so it won't easily come off with a solvent. It's very thin so blasting should go quickly.

I think electrolysis would be problematic. The ink probably doesn't conduct electricity so you would have serious pitting. Too complicated for this application. Be Earth friendly with your recycling project. Use clay, fly ash or bicarb. I like bicarb for safety and easy disposal.
 
  • #13
chemisttree said:
You might consider blasting the can with dry bicarbonate. It is used to remove grafitti so it will be abrasive enough to cut the paint and mild enough to save the can and leave a water-soluble residue (bicarb!) on a matte finish can. No pesky silica to breathe in and no serious hazards with SiC.

The ink is crosslinked with UV light I believe so it won't easily come off with a solvent. It's very thin so blasting should go quickly.

I think electrolysis would be problematic. The ink probably doesn't conduct electricity so you would have serious pitting. Too complicated for this application. Be Earth friendly with your recycling project. Use clay, fly ash or bicarb. I like bicarb for safety and easy disposal.

Wow, that is genuinely genius. If you combine the tumbler with the soda, add time, then cut the cans into strips or blow them back up... you essentially eliminate manual labor. I'm doing the "We're not worthy" Wayne's World bow to you right now.

I did check, and you're right: the paint is NOT electrolytic, it's just standard aluminum varnish/enamel applied by a rapid rotary sponge. Makes sense... you don't want that paint coming off to anything less than serious abrasions: makes your product look "used".
 
  • #14
Just clean it with acetone
 
  • #15
wazani said:
Just clean it with acetone

Hi Wazani,

I've tried it. It don't work at all.
 
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  • #16
What prevents you from painting directly over the existing label?
 
  • #17
pantaz said:
What prevents you from painting directly over the existing label?

Because I need the exposed aluminium in order to apply an other layer by mean of electrolysis.
 
  • #18
Hi Juba
visit this site;
may be solving the problem
 
Last edited by a moderator:
  • #19
wazani said:
Hi Juba
visit this site;
may be solving the problem


Thanks a lot. I will take a look.

I really apprciate your help.
 
Last edited by a moderator:

1. What information is typically included on a label of an aluminium soda can?

The label on an aluminium soda can typically includes the brand name, flavor, and logo of the soda company. It may also include nutritional information, such as calories and ingredients, as well as a barcode for scanning at the register.

2. Why are labels on aluminium soda cans made of a different material than the can itself?

Labels on aluminium soda cans are typically made of paper or plastic, while the can itself is made of aluminium. This is because the label needs to be easily removable for recycling, while the can needs to be durable and able to withstand the carbonation and pressure of the soda inside.

3. How are the labels applied to aluminium soda cans?

The labels are applied to aluminium soda cans through a process called "roll-fed labeling." This involves the label being printed on a continuous roll of material and then being fed onto the can as it moves along the production line. The label is then sealed onto the can using heat or adhesive.

4. Are there any regulations for the labeling of aluminium soda cans?

Yes, there are regulations set by the Food and Drug Administration (FDA) for the labeling of all food and beverage products, including aluminium soda cans. These regulations dictate what information must be included on the label, such as nutritional information and any potential allergens.

5. How does the label on aluminium soda cans affect the recycling process?

The label on aluminium soda cans does not affect the recycling process as long as it is made of recyclable materials. However, if the label is made of non-recyclable materials, it can contaminate the recycling stream and make it more difficult to properly recycle the can. It is important for consumers to check the recycling guidelines in their area to ensure they are properly disposing of their aluminium soda cans.

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