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Conformal coating rework jumpers

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RWD

#76411

Conformal coating rework jumpers | 3 October, 2016

I am doing some rework to my CCA. I then need to conformal coat the board. I'm using Humiseal 1A33 GEL and my jumper wires are teflon coated. I understand the chemical interaction between the 2 products. My question is "Is this an acceptable practice? Do i need to itch the wires?

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#76418

Conformal coating rework jumpers | 4 October, 2016

IPC-7721, Section 6.1, Jumper Wires, Jumper Wire Selection #5 states: "Recommended wire is solid, insulated, plated copper wire, 22 to 32 AWG with a heat resistant insulation. Wire with tin-lead plating may be restricted due to environmental laws."

Yes, etching is a common method to condition fluoropolymer coated jumper wires prior to staking and /or applying conformal coating.

Often, teflon coated wire is not the first choice of materials in hi-rel products.

Select a wire to match current handling capacity of the circuit to be replaced.

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#76433

Conformal coating rework jumpers | 8 October, 2016

A friend in the contract coating business said: "... ask why the wire is [teflon] coated in the first place, as only the solder joints should be coated in this situation as the flexing/bending of the wires will cause the coating to crack and flake off of the wires. If this were a board that we would be coating, I would only coat the solder joints here."

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