Changing from alcohol-based to water-based fluxes - is it that simple? • Future Supplier Hub

Alcohol for the production of alcohol-based fluxes is getting more and more expensive and rare. Many electronics manufacturers are considering whether the use of water-based fluxes might be an alternative. But changing between the two types of flux is easy. Markus Geßner, Marketing and Sales Manager at Emil Otto, shares his expertise.

A: What is the difference between the two types of fluxes when it comes to soldering results?

I can only refer to our products, but as shown in our tests and according to our customers who use water-based fluxes the soldering results are very good and in some cases even qualitatively superior to alcohol-based flux products.

B: When should I avoid using water-based fluxes?

If there are components on the assembly that are sensitive to higher temperatures we recommend using an alcohol-based water-based flux. The temperature in the preheating process are 100°C due to the boiling point of water with water-based fluxes. Alcohol or alcohol-water based fluxes with an alcohol content of 70% evaporate at a temperature of 80 to 90°C. As an electronics manufacturer I have to take this temperature difference into account.

C: Do you support interested manufactures when changing fluxes?

Of course we actively advise our customers. This means that we select a comparable, water-based flux, even if the company has used competing products up to now. So far we have always found an alternative. We are also happy to supply small quantities so that customers can test the product. D: Is a new certification of the soldering process necessary afterwards? That depends on the end-user or the internal quality management and of course it also depends on the industry and the end product. Ultimately it is an economic decision: do I pay high prices for alcohol-based fluxes or can I no longer supply my customers because alcohol-based fluxes are no longer available or do I continue production with water-based fluxes, with lower purchase prices and delivery guarantees. In such cases the question of certification may become secondary.”