Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989





-----

Iridite, Gold or Yellow?





2000

Q. I'm a Manufacturing Engineer who needs to find a standard for Iridite and what is considered yellow and what is considered gold... if there really is a difference. I have vendors that send in very different colored pieces and we want to be able to quote a standard when ordering parts.

Phil Nutting
- Beverly, Massachusetts



First of two simultaneous responses-- 2000

A. Hi Phil,

This is straight from ASTM B449 [affil. link] "Standard Specification for Chromates on Aluminum"

Section 4.2 - Finishers can seldom guarantee to supply exact shades of color with chromate conversion coatings. If it is necessary to have exact shades of color, it is possible to dye chromate coatings having a coating mass greater than 0.4g/m2 to obtain a wide range of colors.

Basically the only way to spec a chromate is to just give a spec and select a color range of 2 parts, maybe a light yellow - medium yellow OR medium yellow - dark yellow/gold color.

I can back this with my own personal experience. Most of the time we achieve yellow iridescent coatings to a light gold tone. Either of these is acceptable to the standards spec and actually the lighter tone is more acceptable if the part is to be coated or painted with rubber as it has been adhesion properties because of the thinner coating weight.

Good Luck to you Phil, if you have any questions feel free to ask away

Matthew Stiltner
plating company - Toledo, Ohio



Second of two simultaneous responses-- 2000

A. I have never heard of a standard for color with chem film. It has to be an agreement between the vendor and the customer.

Concentrations, pH, time, temperature, age of the bath and etch will affect color. Alodine used to go to an old gold color on the high end, while Iridite tends to be slightly more of a reddish brown.It is possible to get the same color out of either, but it takes some work. Most people running a chem film tank are happy to be able to get a nearly reproduceable color on the same alloy and same heat treat status.

James Watts
- Navarre, Florida




March 30, 2012

Q. I am using a new vendor to Alodine parts. The parts we received back were extremely light in color and have a rainbow tint to them. Currently we Alodine to MIL-DTL-5541F, class 3,color: gold. Can anyone tell me why the parts are like this?

4462

Jeff Cole
- Butler, Pennsylvania



April 4, 2012

A. Hi Jeff,

The colours you are seeing are typical for MIL-DTL-5541 coatings, although for a Class 3 they actually look a bit on the heavy side. The iridescence you are seeing is also typical of Alodine coatings, it has to do with the way the coating reflects light. I don't think you have anything to worry about.

Brian Terry
Aerospace - Yeovil, Somerset, UK


none
finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2023 finishing.com, Pine Beach, New Jersey, USA