Contamination from an Aluminum Flux Tank

Phil
Welcome to Board Talk. This is Jim Hall and Phil Zarrow of ITM Consulting, our daytime jobs here to answer your questions on process, equipment, materials, and all the other fun stuff that makes SMT the exciting adventure that it is. 

Today's question is from a Mr. SS. "If we use a flux tank with our wave soldering system that is constructed from aluminum, and we use water-soluble flux, could the flux become contaminated by contact with the aluminum tank? Well, I guess the question here, Jim, is: What the flux is going on?

Jim
On a totally technical standpoint, I would say, yes, there's some concern. The the bigger question is, what water-soluble flux? What is this formulation, and what is its reactivity with aluminum? The real thing that jumps out here is why are you asking us this?

We did not formulate the flux. We don't know what's in it. We don't have any technical data on the flux. Water-soluble is a very generic name. These fluxes are formulated from a very complex mixture of a lot of different chemicals to give you the exact properties that you want to perform well throughout the whole wave soldering operation; flux application, pre-heating, soldering, de-bridging, and so forth.

Why hasn't your flux supplier given you this information? All manufacturers of materials, such as fluxes, pastes, solders, and equipment for that matter, maintain a technical service department for answering technical questions about the application of their products to individual customers.

I can only assume that you haven't established that relationship with the technical services from your flux supplier, or your flux manufacturer, and that's why you're having a question like this.

Perhaps you buy directly through a sales representative that may not have this technical information, but it is certainly worthwhile, and I would say required with any materials, certainly critical materials like flux.

When you start using a new flux, or preferably before you start using it, you establish a relationship with the technical service people from the manufacturer. They're the ones who are going to know how they react with aluminum or any other materials in the conditions that you're going to be operating.

You should do this before you have a problem, because it may take some time. It may take some phone calls getting to the right person who has the actual technical knowledge.

Sooner or later, you're going to have questions like this and the ability to get that information quickly can be very valuable operating an efficient and cost-effective manufacturing process.

I remember that time I was out in the desert in Arizona, and we had a problem with a flux that was being used by one of our customers. We were on a conference call and we called the supplier, and the technical expert that we knew was on vacation.

We had to get somebody else and it was painful, because this person didn't know us. This was a technical person. He was very concerned about talking openly about potential problems. Whereas, if we had been able to contact the person who we had a relationship with, we know that person would've been much more open giving us honest, complete technical support.

Phil
You, as a customer, Mr. SS are entitled to full disclosure of how the material that you're buying is interacting with anything else you have. We're fortunate in our industry that we have very good data sheets. In general if a data sheet comes up short, call the applications person.

You'll be serving two purposes; one, you're going to find out the information needed, and two, you're going to keep somebody employed somewhere and give them a sense of self-valuation.

Jim
And giving them the feedback regarding situations that their customers are actually dealing with when they try to apply their materials.

Phil
So, don't be shy. That's about it for this installment of Board Talk. 

Whatever you do, don't solder like my brother and keep the kids away from those aluminum flux tanks.