Painting the buttons would be a bad idea I reckon as
1. It would slightly alter the shape / fit
2. The paint would wear off
I found this too ...
Now, once the powder is mixed with inks and painted or silk screen printed, the lifespan is over 5 years if used indoors and 1 to 2 years in an out door environment. Plastic molded products have a longer life span of over 10 years.
You have to order 5kg which will cost about 115$, but they can get sample batches.
Does anyone have the right experience / facilties to make up the buttons from this material.
As mentioned, no soldering, and personally I think they would look OK.
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LTJ