Potassium aluminum fluoride (flux) residues and interactions
Almost all fluxes used show silicate reaction and sludge formation due to silicate reduction occurring rapidly, which we could already see by the formation of jelly on the first and second sides. In addition, there is the permanently progressing surface corrosion of aluminum, as well as the formation of bulky corrosion products with embedded flux residues, which then leads to the already shown crumbs and blockages of the cooling channels. For the very interested I had once a rough scheme of the respective influencing factors and their interactions.
Based on my first article, I would like to show another concrete application scheme, which also shows the percentages of the ingredients used in the coolant. Even if to many the 40% glycol coolant (including corrosion inhibitors) seems a lot, the ratio used here shows the procedure when using aluminum radiators and the occurrence of higher temperatures. In a normal PC and with only copper in the circuit, the water ratio could of course be much higher. But glycol (along with inhibitors) doesn’t hurt either, and better safe than sorry.
Which brings us back to the cost of the coolant and of course what you get for the money invested and what is really resistant to flux influences. Unfortunately, quality has its price.
Summary and conclusion
Today we learned another important lesson: residues of potassium aluminum fluoride, also known as flux, react with the anti-corrosion additives, the silicates, in the coolant. When the silicate is used up, the glycol forms an aluminum hydroxide sludge. This sludge can then clog the ducts and pumps, leading to complete failure, especially if the engine overheats. This discovery has significant implications for manufacturers. Even the smallest amount of flux residue (potassium aluminum fluoride) in the radiator must be avoided at all costs! This can be achieved by using a suitable, non-corrosive flux during the brazing process.
In addition, thorough flushing of the inner surfaces and ideally also passivation, for example by coating, is essential for reliable cooling performance. For the coolant, water-based coolant systems should be based on OAT glycol coolant. For those willing to invest more, there are even new coolants based on the “green chemistry” of organic fluoride fluids. These promise particularly efficient heat transfer from electronic components. The trusted manufacturer takes care of the rest.
This is where the circle closes: If the own manufacturer already purchases incorrectly due to cost reductions or has it produced by third parties, even the nicest packaging will not help. Corrosive fluxes in cheap aluminum radiators are not a solution, but always the source of the problem. Apaltek is probably only the tip of the iceberg of companies that, for cost reasons, pass on such products without closer inspection, which actually have no place in a proper AiO.
I had already written something at the beginning about the victims on the supplier side. It can affect anyone whose quality management is not equipped for such products and the associated technical pitfalls. This underscores the need for careful testing and inspection procedures in the manufacturing and supply chain to ensure that only high-quality components are used.
In the case of the 1st version Lian Li Galahad 360 (and also the identical Galahad 240), however, I have to issue an explicit purchase warning, because such a product should be completely taken off the market. That there is now a version 2 (certainly for good reason) it is completely incomprehensible to me that Lian Li simply leaves the defective product on the market. Here the total failure is already included in the purchase.
My very special thanks go to Rene Schlüter (BastelNerd) for letting me use his Galahad pictures and feedback, to the colleagues from the industry for your professional support and the calmness in view of the occurred damages, which normally should never have happened, if a good quality management would take effect.