No-clean” indicates that the product requires cleaning method as defined by IPC no-clean standard and does not mean that the flux leaves no residue. No-clean rather means that the flux can be left on PCB for several consecutive SMT assemblies, also won’t cause corrosion if left indefinitely. The Chip Quik SMD291 is okay and is more readily available from reputable dealers than the Amtech outside of the US. I just looked that up because I haven't heard of the Alpha brand before. It turns out that this is a solder paste Flux is what allows solder to flow. If you've created a bridge, need to solder a jumper in a small area, or are reflowing a chip to try and remove corrosion - good flux will make your life easier. I spent almost a whole day looking through different offers now (wasted would be a more appropriate expression), so I'm now turning to you and would kindly ask about some recommendations.

When it comes to soldering Sn60/Sn62/Sn63 leaded MT alloys using Hot Air station the V2 formulation would be one of the first choices for the handcraft/hobby/rework - V2 chemistry instantly wets Sn/Pb MT alloys but most importantly it has sufficient body to withstand rework with Hot Air station for extended period of time. Including plunger, metal blunt dispensing tip, and "Genuine Product" AMTECH soldering profiles card Amtech flux is sold from Deep River, Connecticut and made in the USA. So STOP BUYING IT FROM ASIA!! HydraCoat-UV 2% - Conformal nano-coating 2% polymer UV-traceable - Ultra-Thin Conformal Nano-Coating - Industrial Strength Silicone, Acrylic, Glass, Metal, Ceramic Coating - Fast-Drying - Easy To Apply in Automotive, Electronic Systems I'm now wondering if the solder paste I received is authentic or not. Just watched this video and from it I got that AMTECH separated from Inventec. Is this for real?https://www.banggood.com/2pcs-AMTECH-NC-559-ASM-PCB-BGA-Reballing-Solder-Flux-Paste-10CC-p-960102.html Optimal viscosity - 40-52 (Malcom @ 10 RPM/25°C (x103mPa/s)). High temperature compatible (up to 300°C/600°F). Surface insulation resistant. No copper mirror breakthrough. Low electrochemical migration (< 1-decade drop). May contain up to 7% w/w of ethoxylated 4-nonylphenol (NPE can be harmful to aquatic organisms - dispose of responsibly avoiding water drains)

I just got RMA-223-TF flux from https://amtechdirect.com/ and tried it out on a small kit. It's pretty difficult to clean up. I tried to clean it with isopropyl alcohol.

The conductivity test is absolutely nonsense: it should be done AFTER the flux has been activated ; it is also true that I _always_ wash my boards with IPA. Refrigeration is not necessary and will not extend product shelf life. If the material has been refrigerated - consider 3-4 hours to normalize at room temperature.