What The Flux: Buy It Or Brew It Yourself

Flux generally makes our lives easier. It’s the best bet when trying to prevent solder bridges with fine-pitch components like you see here. But it is also indispensable when it comes to desoldering components from a board (we’re talking just one component without disturbing all of the others). But have you ever looked at what it costs to pick up a syringe of liquid flux from an online retailer? In addition to the cost of the product itself there’s usually a hazardous material handling fee that is rolled into the shipping cost. So we were happy that [Christopher] sent in a link to the DIY flux page over at Dangerous Prototypes.

The concept is simple enough. Mix some rosin with some solvent. Turns out these items are really easy to source. The solvent can be acetone (which you may have on hand for removing toner transfer from freshly etched PCBs) or plain old rubbing alcohol. And an easy source for rosin is your local music store. They sell it to use on bow hair for String players. Grind it up, throw it in a bottle and you’re good to go. Now does anyone know where we can source needle-tipped bottles locally?

For those that still just want to buy flux we highly recommend watching part one and part two of [Ian’s] flux review series.

Decapping Integrated Circuits With Sap

[James] is interested in reverse engineering some integrated circuits. One of the biggest hurdles in this process has always been just getting to the guts of the chip. He used acetone to dissolve the plastic case but had trouble getting through the epoxy blob. Commonly, the epoxy is soaked in nitric acid for a few minutes but [James] didn’t have access to that chemical. Instead he popped into the local music store and picked up some rosin (used to make violin bows sticky enough to grab the strings of the instrument). After boiling down the rock-hard rosin and the chip for 20 minutes, he got a clean and relatively undamaged semiconductor that he can easily peer into.