# Mask Anodising - multi colour



## BradG (Sep 23, 2012)

Hello Chaps
Ive not posted any pens in a while due to having a very busy agenda this year, but im still floating around.

The last item i turned was a rattle for scuba diving, and while doing this i made a tutorial on how to anodise and dye with more than one colour.

Hoope this helps! . I believe we could come up with some very eye catching pens using this method, especially with multiple layers

It also gives us a way of personalising metal pens without having to go for etching or engraving which can be felt on the surface








*Watch the tutorial here:*
*http://www.youtube.com/watch?v=8OpewWuDJJE*







And for those which missed it, heres a three part video tutorial on anodising which you will need to complete before trying mask anodising





http://www.penturners.org/forum/f28/anodising-video-tutorial-97063/


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## mredburn (Sep 23, 2012)

Having tried it with the bleach We also found That they use Muriatic Acid as a stripper using the same techinics. We (Marshall and I)  had it take longer than a few seconds with the bleach with the dies we are using.


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## BradG (Sep 23, 2012)

I too have had difficulty with certain coloured dyes, which i have put down to them not being organic

Muriatic acid sounds interesting, i shall read up on it. I have seen great results using nitric acid, though i am uncertain as to whether that was a general method which would work just as well with all dyes or if complications could arise with certain colours. more research and experimenting needed.

What i will note however is when i struggled once before with the bleach technique i was using Red. i went from bleach to a weak sulphuric solution and that bleached it out,but not in seconds like it does with the organics.


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## skiprat (Sep 23, 2012)

Hi Brad, I really enjoyed watching all your videos. Thanks !! Just like watching 'How It's Made' :biggrin:

Couple of questions please. ( I may have missed the answers in the vids )

When you use the vinyl stickers you get made or any other stickers for that matter, why don't they peel off in the hot water, or doesn't it matter?

Next, what do you use to polish the white crud off and get the gloss that also doesn't scratch away the coloured finish? 

Lastly, when you were explaining about the impure welding rod eventually giving a poor contact, I was expecting you to connect the pos wire directly to the Jig. In fact I thought I saw a hole where you could have used a banana plug. But as you connected the lead to the welding wire, why wasn't the poor contact created between the welding wire and the Jig?

Very interesting tutorials Brad. Keep 'em comin' !!:biggrin:


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## BradG (Sep 23, 2012)

Hi Skip,



> When you use the vinyl stickers you get made or any other stickers for that matter, why don't they peel off in the hot water, or doesn't it matter?


 
Vinyls waterproof, and the adhesive on the back is super tacky. its exactly the same material used for sign writing vans so as you can imagine it takes some abuse



> Next, what do you use to polish the white crud off and get the gloss that also doesn't scratch away the coloured finish?


 
good ol' plastic polish sold for cars for buffing your bumper or dash board. its a mild abrasive so does a fantastic job on the surface without effecting your work. also, dont use caustic soda for cleaning, as that will give you a matt finish. if you look at the pens in my gallery most of those have a matte finish



> Lastly, when you were explaining about the impure welding rod eventually giving a poor contact, I was expecting you to connect the pos wire directly to the Jig. In fact I thought I saw a hole where you could have used a banana plug. But as you connected the lead to the welding wire, why wasn't the poor contact created between the welding wire and the Jig?


 
The issue of using a banana plug, is that i would have had to of submerged the banana plug in the acid bath too. and as its not aluminium, it would just dissolve into dust. ( if you ever snap a tap off in a piece of aluminium, drop it in an anodising tank... the tap will dissolve leaving the aluminium undamaged  )

if i were to bend the welding wire into a hook and hang the piece on it, a crustation of smut would form on it where the impurities have dissolved, and therefore insulating the aluminium breaking the contact.

To overcome this, i hammer a piece of rod into a hole (as you spotted) what gives more than a tight fit. because of this tight fit, the acid does not get between the two surfaces where they are making contact, therefore protecting them from anodising. only parts what are exposed to the liquid acid will anodise. That make sense?

In an ideal world, i wouldnt use aluminium at all and would strictly used grade 2 titanium as you can just hang the pieces on it without having to make a jig and just keep using it over and over. Also, you dont have to include the surface area of the jig when calculating your current consumption when using titanium, like you with with an extra hunk of ali in your tank. 

This is what i want, but the cost of postage from the states is ultra high.... bit too high to swallow. still searcing for a UK supplier
Titanium Saw Teeth Anodizing Utility Rack 4 Way 96 | eBay



Very interesting tutorials Brad. Keep 'em comin' !!:biggrin:[/quote]


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## seamus7227 (Sep 23, 2012)

very informative video Brad! thanks for sharing


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## skiprat (Sep 23, 2012)

Thanks for the answers Brad.

You wouldn't want to get an itchy nose with that thing in your hand !!:biggrin:

How about using stainless welding rods bent into a similar spring scissor shape? Can stainless withstand the acid mix without polluting the acid?


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## BradG (Sep 23, 2012)

skiprat said:


> Thanks for the answers Brad.
> 
> You wouldn't want to get an itchy nose with that thing in your hand !!:biggrin:
> 
> How about using stainless welding rods bent into a similar spring scissor shape? Can stainless withstand the acid mix without polluting the acid?


 
nope it would turn to dust.the only things you can put in the tank is lead, aluminium, or grade 2 titanium  anything else will corrode and pollute the bath


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## skiprat (Sep 23, 2012)

LOL, I'm finding this whole topic fascinating and being a fan of stainless I couldn't let my favourite metal be beaten. :biggrin:

Check out this site Brad, it seems there may be some stainless steel that you could use depending on temperature and % of acid, after all ( I think, anyway ) 

I know zilch about the acid or even the process, but you said to leave the new diluted solution overnight to cool down. Does it get hot again when doing it's thing on the ally? From the way I read the article, provided it stays within a temperature range, and a % dilution, then even 316 stainless would / could work. 

Worth investigating anyway, even for the interesting read.:biggrin:


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## BradG (Sep 23, 2012)

Everyone loves a tryer :biggrin:



> Sulphuric acid is oxidising when concentrated but is reducing at low and 'intermediate' concentrations.
> The response of most stainless steel types is that in general they are resistant at either low or high concentrations, but are attacked at intermediate concentrations.


 
To anodise, you create an oxidised layer over the surface of the metal. in order to do that you need an intermediate concentration. at this level it will corrode stainless steel.

The above quotation is stating it has a level of resistance which can be controlled when certain concentrations and temperatures are mainted, but unfortunately not high enough to withstand an anodising process.

Same would apply to hard anodising (before you find that :biggrin: ) which involves using in effect refridgerated acid and high voltages.


Yes the temperature of the acid does rise slightly during the process but not enough to warrant an issue. if the bath was running all day then temperature control can be introduced to the bath


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## skiprat (Sep 23, 2012)

Hummmph!!!!! Spoil sport !!!:biggrin: Oh well.....

'Tryer is good, Trying-it-on-er is bad' :biggrin:


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## mredburn (Sep 23, 2012)

I have to cool the acid bath, My ambient temperature is above the recomended levels for anodizing of this type. 
 Caswellplating.com has a forum board for anodizing if you want to check it out Skip.


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## BradG (Sep 23, 2012)

Apologies, I had forgbotten to mention those in warmer climates 

Skip and I wont have that issue here in the chilly UK


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## 76winger (Sep 23, 2012)

Really informative video Brad. Great work on it and the pen!


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## BradG (Sep 25, 2012)

Skip,

Take a look here
http://www.euro-inox.org/pdf/build/Finishes02_EN.pdf

Some great finishes here for your favourite metal.

I think it would be great to experiment with the etching and the electrolytically coloured finishes.

I do actually have an etching tank full of ferric chloride which i use for etching copper clad fibreglass boards for manufacturing printed circuit boards. I am curious if the same etchant could be used on stainless? 

In a nutshell, the process is:

apply the mask
apply the layer of the area you want to keep
expose to UV light for 300 secs
place piece in weak caustic (I use a teaspoon per litre)
this stips off all the part which has been exposed to UV. the mask under the layer you applied was protected from UV.
This leaves you with just the pattern on your piece which protects the metal from the ferric chloride.
Leave in the tank for however long to corrode the exposed area
remove remaining photoresist by either UV exposure or polishing

If you send me a piece of stainless il experiment with it for you if you like?


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## skiprat (Sep 26, 2012)

BradG said:


> If you send me a piece of stainless il experiment with it for you if you like?


 

Sound like an interesting experiment Brad.
Do you want to try on a complete pen or just some stainless?  

Would the unmasked areas then become matt by the etching process?

Email me your address and when I get home on the weekend, I'll post it.

No need to send it back:wink:


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## BradG (Sep 26, 2012)

just a piece of stainless would do it, i wouldnt want to ruin a pen trying lol

il pop the address over to you and see what we can come up with

yes it will go matte, though i am curious as to whether we can seriously impact the depth of the unmasked areas in a controlled manner.. could create some interesting patterns if so


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## mredburn (Sep 26, 2012)

Would  nitric acid using a wax resist do the same thing?


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## BradG (Sep 26, 2012)

for etching Mike? Sure, but different acids will give you different results depending on how aggresive they are


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## skiprat (Sep 29, 2012)

Brad, I just made our local post office with minutes to spares.

I've sent a couple small bits of stainless. Grade A2 and A4 as well as a tube of titanium, but I can't remember what grade that is. 
The stainless is probably only good for practice, but you might get yourself a skinny pen from the Ti tube. Have fun. :wink:


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## BradG (Sep 29, 2012)

hey heyy.

Much appreciated that will give me something to play with. ive ordered some special resist, so il hang fire until that arrives from hong kong before i commit the metal to the plunge 

needless to say il post the results


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