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DIFFERENCE BETWEEN MIL-C-5541 CLASS. 3 AND CLASS. 3 GOLD

NEED TO KNOW THE DIFFERENCE BETWEEN MIL-C-5541 CLASS. 3 AND CLASS. 3 GOLD CAN I ACCEPT A PROCESS CERT THAT STATES CLASS. 3 WHEN I REQUESTED CLASS.3 GOLD ?

VINNY FLORES
BUYER - SANTA ANA, California, USA
May 16, 2008

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May 23, 2008

Vinny,

When you ordered Class 3 Gold, did you really know what you were ordering? As far as I can remember there is no colour call up in MIL-C-5541. If the parts have been released to MIL-C-5541 Class 3 then they must meet the requirements of the specification, otherwise the release would not be accurate. Assuming that you haven't specified a type 2 (non-chromated), then the probability is that you will have a gold coating, or something approaching it. If you are specifying class 3 you want a low electrical resistance, is that correct? To obtain this the coatings tend to be lighter.

The best thing to do is inspect the parts, are they gold in colour? If not then go back to your supplier and ask why they haven't been supplied in accordance with the P/O. If they are gold then I would say that the MIL-C-5541 release would be sufficient.

Brian Terry
Aerospace - Yeovil, Somerset, UK

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There is a color difference between QQP certified materials to comply with 5541. In generalities, Iridite that is put on a bit heavy will have a reddish brown tint to it and still pass the QC portion of the spec. Alodine tends to be more yellow, with a light coating being a rather pale yellow that will still pass the spec. A heavy Alodine will tend towards an old gold color and pass the spec.
The purchase contract needs to be more specific and should have a set of Go-No Go panels for what is color acceptable. The purchaser can work this out with the plater before the contract with no pain.BUT, to just say gold to dozens of platers for a bid WILL lead to contract problems as it does not really say anything.

James Watts
- Navarre, Florida
May 25, 2008