Ok, found the post from a while back, so instead of bumping that thread I'll just copy/paste over post:
After searching long and hard for blank dark grey or black PBT's, none were to be found anywhere so I decided to use RIT dye to try and get the desired shade of grey and black that I wanted. I thought this was a good idea after seeing several successful attempts from other people. I also saw many failed attempts of dying, and I'm shameful to add to this statistics.
I bought blank white PBT caps from qtan, and started my procedures, taking precaution in every step to do it right and not cut any corners since I only had one shot at doing this. First was the prepping, which took a little over an hour. I first rinsed all the caps under running tap water, then shook them dry. They were then submerged and washed under distilled water to get rid of all the trace elements in tap water, and shook dry. They were then submerged under 91% Isopropyl alcohol to get any remaining impurities and oil out. I then used napkins to wipe each surface of every individual cap. Prep was finally done.
Next step was the actual dying process, which took a total of 4-6 hours. I first boiled about a half cup of water to dissolve about half the pack of RIT dye. After mixing it all and dissolving it, I poured this concentrated dye solution in a small pan and diluted it to about half the pan. The heat was turned up to low-medium to get a warm dying solution. Then I put all the caps in, gently stirred, and checked about every 10 seconds. After a few minutes of this, there was almost no change to the white color of the caps, so things started to go wrong already. Finally after 30 minutes, it was starting to turn a different color; it wasn't gray! It was a hint of brown instead. But the color was so light, I figured if I kept it in there a little longer and turned the heat up a little, it should probably get to the right grey. I turned the heat to medium gently stirred it, and after about another hour, it's pretty clear now that this was getting browner instead of grey. The color was still pretty light though. After a few hours of heating and stirring, a lot of the water from the dying solution was lost in the form of steam, so I added more water until about half the pot was full again. I also added some salt to see if it'll help the colors absorb. After a few more hours of babysitting these caps, it was a dark brown instead of the grey I had hoped for :Cry:.
After washing them off and towel drying each one, I also realized they didn't dye evenly. Most of them had blemishes and scratches, and some of them were darker than others. Since I wanted a grey and black them, I put all the larger modifier caps and arrow keys (and the function keys above it) back in the dying solution to turn it so brown that hopefully it turns black. Since it seemed like this process took too long for any change, I turned the heat up just a tad more, and added the rest of the dye packet. After about another 2 hours, it was a very very dark brown, almost black. I took it out, washed it, and dried them again. I put all the caps on my keyboard, and here is what it looks like.
This is what I wanted the colors to look like, except blank keys.
This is how it turned out.
