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White powdery residue following Wave

#5451

White powdery residue following Wave | 2 March, 2001

We are seeing a white, powdery residue following the Wave process. Is this a solder masking issue (poor cure from the PCB mfg) or Wave process related? Any input is greatly appreciated.

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Travis Slaughter

#5453

White powdery residue following Wave | 2 March, 2001

Is this after wave or wash? Its too bad the archives are gone this one has come up a bunch of times. Most of the time its caused by rosen or no clean flux being put through a water wash. There are several other possibilities. You will probably hear we need more info a few times, things like is it on part of the board all over it, kind of flux used, temperatures through wave, and about 500 others.

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#5454

White powdery residue following Wave | 2 March, 2001

This happens to be after the water wash process. These are Burn-In boards so an SMT epoxy is used prior to wave. The flux used is Kester 2331ZX. Would using a thinner cause this to occur? The residue is all over the board. Thanks.

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Travis Slaughter

#5455

White powdery residue following Wave | 2 March, 2001

If the thinner you are using is 4662 and the correct amounts that should not be the problem. Is this the first solder operation? I would start by looking for rosen or no clean flux getting on the boards at some point before wave soldering and not being completely washed off.

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Wister

#5457

White powdery residue following Wave | 3 March, 2001

I had confused by same problem, the reason I found is the interval between wave soldering and cleaning is too long and did not set the temp. of D.I water at 120F~150F. Kester flux is good. Rgs, Wister

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#5472

White powdery residue following Wave | 5 March, 2001

When you say all over the board, please give more detail. Where are they located? [All over wave soldered portion, laminate only, solder mask only, solder only, specific components only, etc]

When you say white residue, what color are they really? [Many "white" residues are actually more gray or yellow, than white]

Can you say something about the date codes of the bare boards? Is this lot specific?

How is it signifant to the problem that these are "burn-in boards"? Do you mean that they were either reflow or wave soldered more than routine? Er what?

And you water wash has what in it?

Got pix that you could post for use to gawk at [oops not that kind of pix!!]?

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Dason C

#5477

White powdery residue following Wave | 6 March, 2001

I have experience to the Kester 2331 water soluble flux long time ago with white residue and it related to the solder masking. Check what kind of the solder mask and ask Kester to do the test for you.

Rgds.

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