Glycol-Based Flux Paste Interaction with Aluminium at High-Humidity Storage Conditions – Aluminium Brazing
Laboratory investigation
Experiments were performer with: small coupons (25mm x 25mm x 0.4mm); alloy: AA3003, both sides clad 10% AA4343 and angles; alloy AA1050. The angles were put on the coupons and some flux paste was applied at the joint area. About two droplets of the paste were applied on each coupon. First set of coupons and angles assemblies was kept in laboratory at ambient temperature and normal humidity conditions. The paste dried out during storage.
Second set of coupons and angles assemblies were stored in a closed plastic containers.Firstly a paper tissue saturated with demineralized water was put at the bottom of the plastic container and then the coupons with angles were placed on top of the paper. There was no direct contact of the flux paste with water saturated paper. After closing the containers they were placed on a standard room heating radiator (temperature around 40 °C to 50 °C) for 2 days, then stored at room temperature for 14 days (~ 22 °C), and again placed on the radiator for 4 days.
After the total time of 18 days the assemblies were removed from the containers, photographed and subsequently dried at ambient temperature. At the end all of the assemblies were washed with demineralized water, and the paste was wiped off by the use of a paper tissue.
