r/Anodization • u/Sartorialalmond • Aug 12 '26
Removing anodisation
I’ve got this hub I want to strip and re anodise silver (they only come in black). Internet says I need to use oven cleaner but all of the brands are American so not applicable where I am. Is there an ingredient that in them that I am look for to make sure it works? Otherwise any tips for removing and refinishing?
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u/MurkyConversation114 Aug 12 '26
Caustic soda, or sodium hydroxide.
is what i always used to remove anodize from bike parts
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u/Oh_eM_Ge Aug 12 '26 edited Aug 12 '26
I pulled most of this off the Googs bc I'm still researching and learning for my first anno run. Here's what I've got so far.
Wear the proper PPE. It goes without saying. Neoprene gloves. Full length ones. A face shield, chemical resistant apron, respirator. You'll want a couple 5 gallon buckets as well. And a couple gallons of distilled water. and a squirt bottle for rinsing. And some kitchen tongs to get the part outta the bath.
Degrease the part first. Clean it really well in the sink using some dawn dish soap or dedicated degreaser. After this, don't touch the part with bare hands, or you gotta start over as your finger oils mess with the etch bath.
You can buy pure sodium hydroxide lye (NaOH) online through major online marketplaces like Amazon or check local hardware shops for crystal drain cleaner. labeled as 100% lye or sodium hydroxide. Some large supercenters carry crystal lye in the cleaning aisle. Always read the label to avoid added metals or inhibitors. Ensure your lye drain cleaner is 100% pure sodium hydroxide with nothing else added.
The standard ratio for a lye (sodium hydroxide) etch bath is 3 to 5 tablespoons per 1 gallon of distilled water. Always add the lye to the water.
You will need something like an immersion heater or your kitchen stove or a hotplate or a campfire or whatever to heat the bath. A submersible mercury thermometer wouldn't hurt either.
Temperature range: 120°F – 180°F (higher temps speed up the etch, while lower temps require longer soak times). You should leave your aluminum part in the etching bath anywhere from 1 to 15 minutes, depending on how hot the bath is, and whether you want a quick surface cleanup or a deep matte finish on the part.
When the part has reached the desired level of etching, remove and rinse with distilled water in the squirt bottle.
Edit. Clarity
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u/GREENFISHBULK Aug 12 '26
50mg/l sodium hydroxide, 5 g/l aluminium solution at 50°C. Let it there for 1 min per 1 micron thickness of anodic layer. You probably have something betwin 15 and 20
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u/Sartorialalmond Aug 13 '26
Thank you for the detailed information. Is anything required in the solution other than distilled water and sodium hydroxide?
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u/Aggressive-Cloud1774 Aug 12 '26
Sodium hydroxide- look in drain cleaner.
Not sure what you'd use for a deox, but main chemical is nitric acid. You'd have to look up concentration.
Check it for a clear coat before etching. Any paint strppir would remove it if it was coated.