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Step 4: File Down the Chip

Picture of File Down the Chip
2019-03-06 14.10.52.jpg
2019-03-21 16.48.43.jpg

Note: The second to last picture above is a different version layout from a newer card from my bank than the four earlier pics. Just to give an idea of some ways that I filed down different chips that worked.

The idea here is to make the chip backing board the least wide that you can since that's the smallest dimension in the ring that you have to worry about. From what I've seen there are usually larger traces running around the chip. Make sure you don't file into these, or any traces that run from these to the outside two pads. These two outermost pads are where the antenna attaches.

If you melted the card down whole, you'll have noticed that the ends of the antenna that runs through the entire card will contact these pads. In my case, it was simply pressure holding the antenna to the contacts. If you have any questions or if your chip looks different, feel free to send me high-resolution pictures of your chip and I'll do my best to advise.

This is why you don't cut too close to the chip area on the card before you put it in acetone if you're not melting it down whole, as you could cut through these traces, and this is why I recommend filing it down gently to get it smaller, is to make sure you don't disturb any of these delicate traces as you work to make this assembly smaller to fit into what you're going to cast. The last picture is an example of what can happen if you aren't gentle enough.