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Cad class 1 red dye  

September 16, 2008

I am plating parts Cad Class 1. Back in WWII nuts bolts washers etc would sometimes come with a redish dye on them. Does anyone know the tech order for making the dye?
Thanks,

Chuck Wahl
Warbird Restorations - Cameron Park, CA, USA

Dyes are generally commerically available from many of the same sources as the chromate conversion coating. Dye will vary from lot to lot so dye matching generally was not done. Check with a dye supplier for suggestions and then you will have to experiment. The depth of dye color (penetration) is directly proportional to the thickness of the conversion coating. Light dye colors appear on thin conversion coatings i.e clear, darker colors on yellow or specific conversion coatings formulated for dye.

Gene Packman
- Great Neck, NY

Years ago we used to dye cad various colours, including red, blue, green and golden yellow (customer didn't want the iridescence of a dichromate finish). The best dyes were proprietary, the ones we used were Sandoz dyes. I don't know if they are still available but if they are I would try one of their standard red dyes.

Brian Terry
Aerospace - Yeovil, Somerset, UK