Trak365 Leak

Very fast service, electrically perfect PCBs, very helpful staff. I have had several PCBs made by PCBway and they have been perfect, but this one has patches of a slightly sticky deposit on the surface. I thought it might be flux but it does not wash off with flux cleaner or acetone and it turns a brown colour in the reflow oven (see photo). This does not cause electrical problems but looks bad and also meant that the PCBs were stuck together. I have now discovered that the deposit will wash off with water, but not the brown marks after reflow - it could be a sugary solution. I hope that will help identify the cause and avoid for the future. Overall, your service is BRILLIANT. This is not a complaint, I just want to help you improve even further.