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The authoritative public forumfor Metal Finishing 1989-2025

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Category: "Anodizing and light metal treatments (Aluminum, Magnesium)"
617/89. Removing calcium & zinc from rinse water on aluminum anodizing line Inquirer often helps others, so especially deserves our help
- 1/24/25
432/48. "Two-step" black anodizing w/tin sulphate: Q&A - 12/21/24
617/87. Anodizing: missed one tapped hole; how to re-do? - 12/18/24
137/75. How to Chromate Conversion Coat ADC12 - 12/7/24
295/19. How to Mask for Hardcoat Anodize - 12/4/24
613/75. Chromate Conversion Coating as Paint/Powder Prep - 12/3/24
415/31. Ultrasonic cleaning of anodizing leaves white stain 2nd Rqst - 12/3/24
533/57. Slime/algae on surface of anodizing tank - 11/27/24
617/74. Anodizing: Small Area That Doesn't Dye
- November 23
617/70. Simultaneous etch-passivation solution for aluminium pretreatment - November 18
144/62. Spot type seal check for black anodized aluminum
- November 14
617/64. Skin products affecting dyed anodizing? - November 1
338/83. Problems in Plating on Aluminum (ADC-12) - October 30
617/62. Delay between Aluminum Chromate & Powder Coating - October 24
617/44. Black Anodize Blemishes & Spots
- October 14
617/51. Problem dying anodized aluminum green - October 11
617/37. Is Discoloration an Etching Problem?
- October 11
617/26. Black dust on dyed black anodized aluminium
- September 28
279/90. Anodizing is Flaking Off of 7075 Aluminum Parts - September 28
600/68. Aluminum sheet shows stripes after chromate conversion coating
- September 23
617/36. Affect of water on 6061 anodized aluminum
- September 21
617/41. Aluminum certified as the same etches differently
- September 18
242/36. Epoxy primer not adhering to conversion coated aluminum (failing bend test) - September 9
515/73. Anodizing rectifier & chiller sizing
- August 28
423/62. What were the two types in the old Mil-C-5541 spec? - August 27
617/16. Odd porosity on anodized threads AFTER sealing
- August 26
434/84. Low Anodizing Thickness in Gap between Plates
- August 26
615/29. Anodized Aluminium edges not taking dye very well - August 12
67/84. Need 0.5 Ra after Anodizing - August 6
400/35. Desmut can't remove black coloration from etching - August 5
616/99. Alloy wheels: is chrome plating or anodizing better? - August 1
34822. Temperature limit for chromate conversion coating on aluminum - July 25
61690. Improve Labeling Process on Anodized Aluminum - July 25
61689. Current Density for Electropolishing Aluminium - July 24
61688. Best pretreatment for tin plating on aluminum? - July 24
61687. Chemical No. 21 Ferric Nitrate Bright Pickle of Magnesium - July 24
36275. Sandblasting aluminum parts prior to Alodine coating - July 24
30512. Best Sulphuric Acid Concentration & Influence on 720 Rule - July 15
61674. Some Black Anodizing Came Out Blue
- July 4
61239. Dye keeps flaking off along with some of the anodize - July 1
14851. Salt Spray Results vs. Panel Preparation - June 19
56581. Rainbow effect / defect on anodized aluminum? - June 15
1594. Eliminate stray currents in stainless seal tank - June 5
36556. Coatings on Aluminum for Electrical Insulation - June 4
61653. Shot Peening & Anodization to Maximize Fatigue & Corrosion Resistance of 6082-T6 - May 30
44778. Hard Anodizing Defects: stains on brand new Kawasaki forks
- May 27
616/73. Brite Dip & Anodizing on sandblasted aluminium shows white spots/blooms - May 25
61656. DI Water is Etching Anodized Aluminum in the Cleaning Line - May 20
9519. Plating on Aluminum Q&A - May 3
61664. Magnesium corrosion with TCP treatment
- May 3
41531. Cleaning anodized parts with acetone and ultrasonics stains them - April 14
48664. Wet Tape Adhesion Test per MIL-DTL-5541 - April 3
37317. Hexavalent chrome in surface of chromic acid anodized parts - March 21
61636. Black Marks on Extruded Aluminum I-Beams
- March 20
9142. High Thermal Emissivity for Aluminum Electronics Boxes - March 19
56977. Mirror polishing thin aluminum sheet on both sides without warping - March 10
26894. Problems in cold sealing of anodized aluminum - March 2
61637. Halo spot in Hard Coating 6061-T6 Aluminum
- February 22
43248. Two-step" black anodizing has reddish powder on it - February 19
61626. Trouble with Iridite 14-2 only on 2024
- February 19
61639. White patches only when anodizing 60xx
- February 19
3437. Anode to Cathode Ratio, Size, Spacing, Placement in Anodizing - February 12
61633. Methods for evaluating surface preparation steps during the anodizing process - January 29
43777. White spotting on black (and red) anodising - January 11
59981. Calculating required aluminum anodizing time - January 11
53012. Electrolytic Etching of Aluminum - January 10
4422. Aluminum Anodizing Color Match Problems
14441. White spots in black anodizing
61610. Large Plate anodizing problems
- December 27
61623. Contaminant Build up in Anodize Line Rinse Tanks
6326. Hard anodized parts are matte & dull; should be smooth & shiny
- December 11
36602. Black rubs off anodized parts
- November 25
33883. Problems in Plating on Aluminum, including alloy selection - November 21
21693. Sealing Aluminum to prevent oxidation? - November 9
61589. Snowflake corrosion on Duranodic anodized parts - October 25
47152. Dissolving aluminum with caustic soda - October 24
61581. Black anodize gets white stains only on large sheets
- October 22
56514. Minimum time between chem-film and priming - October 22
14122. Re-anodizing Aluminum which has been previously anodized - October 19
37104. Trying to mild etch High Mg Al alloy
0606. Water quality / chloride contamination in anodizing
22496. De-smutting/De-Oxidizing of aluminum - October 3
• Anodizing supplier is RoHS compliant but not RoHS certified?
• Looking to permanently whiten aluminum
• Failed Taber testing on hard anodizing
• Two-step black color anodizing Q&A, Problems & Solutions
• Dissolving aluminum with caustic soda - September 15
• Reduce anodize thickness by leaving in tank with power off? - September 14
• Chromate Conversion Coating of Cast Aluminum: Problems & Solutions
• Gold hard anodising with anti-bacterial silver
• I need to to know exact chemical composition for MIL-DTL 5541 conversion coatings - September 1
• Caustic Etch Analysis -- aluminium anodizing
• Calculations & formula to reach 25 micron [0.001"] anodizing thickness
• Preventing yellow/tan discoloration of molded aluminum
• Black spots problem in anodized aluminum - August 15
• Will black anodized chassis dissipate heat better than clear
• Zincate formulas for plating on aluminum
• Can sealant surfactants be removed? - June 30
• Coating mass/weight for ASTM B449 colorless
- June 29 Inquirer often helps others, so especially deserves our help
• Aluminum Anodizing Color Match Problems - June 25
• Alodine 1200 is now coming out clear instead of dark - June 25
• Anodized aluminum refuses to dye - June 25
• Want very thin Anodizing on Aluminum
• Anodized Aluminium edges not taking dye very well
• Need black anodizing that is UV-proof - June 9
• Alodine is too dark! - June 8
• Sandblasting of aluminum diecastings - June 8
• Not very successful yet at anodizing - June 8
• Alkaline Etching Bath gets used up really fast - June 8
• Need 'perfect' yellow chromate conversion coating - June 8
• Zinc-nickel plating on aluminum Q&A, Problems & Solutions - June 8
• Crazing/cracking of anodizing from baking powder coating
- June 2
• Looking for lab for corrosion testing of MIL-DTL-5541 samples RFQ: Jacksonville, FL - May 22
• Electrical Resistance/Conductivity Testing of MIL DTL-5541 Chromate
• Aluminium Wire Rod Surface Problem
• Corrosion of anodized 7075 T73 vs 7075 T6 aluminum
• Touching up anodizing with Alodine/Iridite/Chem-film/Chromate
• Customer wants bright black anodizing on ADC12 - April 14
• Problems achieving shiny/glossy anodizing - March 23
• "Neutralizing" sulfuric anodizing solution with nitric acid - March 5
• Bulk anodizing for aerospace
• Bright dip stains the aluminum with grain pattern - March 1
• Roller for adhesion test for chromate conversion coating - February 26
• Problems in cold sealing of anodized aluminum - February 25
• Bending aluminum: best alloys and lubricants
• Aluminum anodizing: Constant current vs. controlling the voltage - January 11
• Thickness of Alodine/Iridite/Chemfilm on Aluminum - January 3
• MIL-DTL-5541 Chem film fails humidity test - January 2
• Burning problem in Hard Anodizing of Aluminum
• Anodising thickness not being achieved - December 31
• Aluminum Anodizing Color Match Problems
- December 22
• Anodizing Discolorization "Leopard Spots"
- December 21
• MIL-C5541-Class 3 Question - December 20
• Chromic Acid Anodizing: Parts are too dark
• Stains in Electrocolouring of aluminum
- December 6
• Pitting and black spots during Anodizing - November 27
• Chromic acid anodizing wasn't sealed. What now?
• Problem anodizing 7075 (7xxx) aluminum
• Can duplex sealing enhance black dye stability? - November 15
• Need Chromating on Aluminium Castings for SST of 400 hours RFQ Pune, India - November 8
• Anodised aluminium temperature resistance - November 3
• Three-in-one aluminum pretreatment process? - October 27
• Type III hard anodize parts burning at the bottom of rack
• Need Screws for Anodizing Racking RFQ Bay Area CA - October 22
• Process flow for silver plating on aluminium - October 15
• Certification of Sulfuric Acid Anodizing voltage
• White spots on 2000/7000 series aluminum only after sealing - October 11
• Problems in cold sealing of anodized aluminum profiles - October 10
• Type III hard anodizing and Taber Abrasion testing - October 10
Inconsistent colour change in anodising; grainy & uneven color - October 8
• "Clear" Anodize on 6061 is Champagne, not Clear
• Need Bulk Anodising Service (or Setup) RFQ: Hungary - September 22
• Anodize Aluminum Nickel Bronze? Thanks! Resolved :-) - September 20
• Anodized aluminum in deionized water - September 16
• Anodizing for Electrical Resistance / Dielectric
• Aluminium corrosion and sodium stannate
• Anodizing current stuck at 1/4 of what it should be
• Tin plating on Aluminum -- is intermediate layer of copper needed?
• Alkaline etch of aluminium prior to powder coating Thanks! Resolved :-) - July 27
• Spalling of sulfuric acid anodizing
• Remove dye but not electrocoloring from anodized aluminum
White Powder/Salts on Anodized Aluminum
• 7075-T6 Poor anodising appearance related to minor differences in composition? - June 23
• Need Phosphoric acid anodize ASTM D9399 RFQ: Thailand - June 17
• Discoloration of MIL-5541 Alodine - June 13
• Can chem-film resist ultrasonic cleaning? - June 12
• Problems with Alodine/Iridite/Chem-film and Blind Holes - June 9
• Salt spray test hours for anodized aluminum - June 3
• Aluminum Alloy Rotogravure Cylinder Problems & Solutions
• Constant voltage anodizing issue: Current out is higher than current in
• Extend Alkaline etching bath life by decanting?
• Burning problem in Hard Anodizing of Aluminum - May 26
• White spotting on black anodising - May 25
• Black spots on anodized surfaces - May 25
• Conversion Coating Process (Chromating?) for Mazak (Zamak)
• Using titanium baskets & scrap aluminum wire as anodizing cathode?
• Issues black anodizing & clear anodizing sandwich panels
• Can't Get Anodized Aluminum Watch Dials Blue Enough - May 13
• Need anodizing theory Thanks! Resolved :-) - May 12
• Problem in shiny anodized product - May 4
• Blueish discoloration on hard anodized parts17
• Black spots on aluminum from anodizing
• Dissolving aluminum with caustic soda - April 8
• Current drop during anodizing - April 7
• Thickness/weight of anodize coatings Thanks! Resolved :-) - April 4
• Chromic Acid Anodizing: Introduction and Problems & Solutions - March 29
• Phosphoric Acid Anodizing (PAA) current & thickness issues - March 17
• Pitting Defect on Bright Finished Aluminium Extrusion
• Setup and startup of a new anodizing line - March 16
• Hardcoating Of Cast Aluminum (ADC12)
• Black anodized parts feel like a chalkboard Thanks! Resolved :-) - March 8
• Anodizing Cast Aluminum - March 6
• Chromate not properly coating 5052 alloy
• Two-color anodizing - February 20
• Anodizing amperage drops to zero - February 20
• How to do printing onto Anodized Aluminum
• Chemfilm & hard anodize on mic 8 aluminum - February 17
• Chromic acid is being dragged into black dye tank (February 15)
• Electrocolouring of anodized aluminum: speckles & white powder stains
• Electroplating / Electrodeposition of Aluminum (February 11)
• Masking/stripping when chromate conversion and anodizing on same part
• Need world-class re-anodizing of a large sculpture RFQ Hudson NY (February 9)
• Anodizing and electroless nickel on same piece (February 2)