Larry Chesterfield
Technical References for Anodizing
Are there any resources to read and keep on hand as references for troubleshooting appearance issues?
Read MoreBlistering of Anodic Coating on 7075 Alloy
We are facing a blister problem on 7075 alloy inside the bore diameter of our cylinder base. We noticed that this problem is occurring during dyeing process and not after hard anodizing.
Read MoreChromic Acid Anodize Failing Salt Spray Testing
We are performing salt spray testing on 2024 and 7075 alloy test panels that have been Type I (Chromic Acid) anodized. The test panels have been sealed in DI water at 96°C (205°F) for 25 min. The panels fail the salt spray test within 24 hr.
Read MoreWhen Black Dye is Not Black
We are sending aluminum extrusions to our outside anodizer for Type II anodize and black dye, and we are encountering several problems, notably that the newly black anodized parts exhibit a greenish tint.
Read MoreSalts Build-up Around The Top of The Cathodes
The aluminum cathode bars in our Type II anodizing tank have become completely encrusted with white “salts” at the solution/air interface.
Read More“Cracking” of the Anodic Coating Under High Temperatures
After anodizing, the parts are annealed at 100°C. Most of the time they will withstand this process without damage, but sometimes the anodic coating cracks. I would like to ensure that they never crack at 100°C.
Read MoreAnodized and Dyed Black Extrusions Turning Green and Purple
We notice that the black extrusions have a greenish cast to them when we receive them from the anodizer. When the parts are exposed to plant lighting and to indirect sunlight, they turn a purplish color after six months or less.
Read MoreProducing a Thick Anodic Coating on 6061-T6
Our customer has requested .004-inch (100µ, 4 mil) coating thickness on 6061-T6. We normally anodize this part to .002-inch thickness. Our process is 28 V, bath temperature 32°F, for 1 hr. We are not sure of exactly what the best procedure is to hardcoat anodize to this coating thickness.
Read More"Snowflake" Corrosion on Anodized Aluminum Parts
One of our customers sends their extrusions to an outside anodizer near their plant. They sent us some samples of their anodized parts that were exhibiting a condition that looked like small snowflakes all over the part.
Read MoreASTM Test Comparison
What is the difference between ASTM B136-84 and B-136-77 for the Modified Dye Stain Test?
Read MoreBlack Power on Die Casting After Anodizing
After anodizing there is a loose, black powder that can be removed just by touch. Can you tell me why this happens and recommend a method to prevent it?
Read MoreDying Anodized Parts With Small Holes
We send our 6061 aluminum bars to an outside anodizer for Type II anodize and black dye. These parts have several very small diameter, blind holes, both threaded and non-threaded. When we get these parts back from the anodizer, the tapped holes will have bleed-out areas of white streaks, and sometimes the holes are filled with a white powder.
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