I am attaching an SOIC Attiny1634 to an nRF24 without any PCB (to save space). The Attiny is held on (upside down with its legs in the air) with a bit of double-sided sticky - so far so good.
I am using the nRF24 pins as convenient connections for programming - also, so far so good.
But I also need a connection to the reset pin and I want one for the Tx pin (for debugging).
I figured I could make them from small bits of solid copper wire soldered to the relevant pins and glued to the bottom of the chip (for strain relief) with some epoxy. But, to my surprise the epoxy got a very poor grip on the black stuff the chip is encapsulated in and the first time I put any force on it it came off.
I then discovered that the black stuff is so hard I could not scratch it (for extra grip) with a scalpel.
I have just cleaned the black stuff with methylated spirit and epoxied it again.
While waiting for the epoxy to set I wonder if anyone has a better suggestion for glue that will be suitable for this job. It needs to have body similar to epoxy - i.e. thin watery glue will not grip the wires.