.... addendum to my ipod-mini modding post ...
https://forums.macrumors.com/thread...od-mini-see-pics.1843060/page-2#post-22198866
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remove Apple applied anodizing by soaking in phosphoric acid for one or two days ... you can buy that from a hardware store as clear-as-water rust remover
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best anodizing receipe i used after some experienced third party advice and experimentation
· 20 to 23 degrees celius ambient temperature
· 2 to 3 amps for a single ipod-mini case (approx 26 square inches exposed surface area)
· 7 to 9 volts (NON-switching power supply)
· 180 minutes
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after removal from anodizing bath (33% battery acid + 67% distilled water, which equals approximately 11% pure sulphuric acid + 89% distilled water) , then rinse, optionally dye, and seal in boiling distilled water
filtered water rinse
filtered water rinse, again
distilled water rinse
optionally, dye in a bath, preheated to 50 deg.C, no additional heat applied, so probably cooled to 40C over 1/2 hour, use distilled water - i used a tall 500ml glass jar placed in a plastic jug so i could surround the glass jar with hot water and cap the 'hot water jacket' with a kitchen sponge -- this can be easily heated in a microwave prior to suspending the ipod-mini case within the jar ... the black dye i got as a powder from ebay, but i suspect it is merely laser-printer / photocopier toner and was opened by border customs inspectors who thought it could be an illegal narcotic ... it had a slight red tinge when applied to the case, but this tinge dissappeared after a few days
to close the aluminium pores (sealing) boil for 1/2 hour ... in distilled water, no sealant chemicals added, as i don't have any ... i just bought a cheap electric kettle / jug to boil the ipod-mini case in
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i used aluminium mig welding wire to suspend case from an aluminium support strip acting as the anode bus bar (positive 7 - 9 volts) placed on top of the anodizing, rinse, dye, and sealing baths, last photo (at the botttom right) shows how i looped it to press fit within the interior of the ipod-mini case, and the support strip which connects to the positive side of the power supply ... the two larger aluminium sheet metal cathodes connect to the negative side of the power supply
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when re-anodizing the case, use no pigment/dye if your want a natural look ... or in some variations i used a colloidal silver ('dye') bath for a subtle silver sheen
i did want to try a 'white' anodize, but never got around to doing it ... a process i thought could work would be to use two dye baths
first is barim acetate (made from barium carbonate and acetic acid)
second bath is sodium sulphate
they will react to form barium sulphate in the yet unclosed pores of the aluminium which is a white insoluble powder
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at the time these photos were taken i was experimenting with recolouring the PVC material used in the endcaps on a unused white ipod-mini click-ring ... the tan vinyl spray was old and lumpy because it was from the bottom of the aerosol can ... in the end, the best results i got for recolouring the end caps was black vinyl (auto uphostery / carpet) dye, removed from an aerosol can, and applied with an air brush
--- tips ---
unremoveable, broken or damaged tiny casing screws WILL dissolve in the anodising bath
excesssive anodizing current will pit the ipod-mini casing, you may be able to see that erosion damage along the edges of the apertures for the end-caps, click-ring and lcd, of the ipod-mini case which i tried anodizing at 4 Amps for 120 minutes
anodizing will not hide (or fill) any scratches or imperfections in the case metal
a short caustic soda solution bath prior to anodizing, say 15 - 30 seconds, will give you a matte anodize finish
i am not responsible for any misuse or mishandling of these chemicals, wear rubber gloves, eye, face and breathing protection, and sacrificial clothes as a minimum - sulphuric acid splashed on your clothes will leave big holes in them which appear after a day or two, or after washing them.
anodizing will release toxic sulphuric acid fumes and a fine mist, do this outside on a warm day, and don't breathe the fumes in
sulphuric acid will permanently stain concrete, bricks, and open-pore ceramics white
do not use these chemicals unattended
store and use these chemicals away from children and animals; keep them in impact and ultra-violet resistant containers
a solution of caustic soda will neutralize sulphuric acid, keep plenty of water and a solution of neutralizing caustic soda around in case of accidents
dispose of unwanted chemicals ecologically and in acccordance with local laws, don't just pour them down the drain
anodizing is an art not a science
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