I am refinishing a set of 4 dining chairs which I believe are made from walnut. I am using a Minwax Dark Walnut stain on them. 2 of the chairs I was able to get to the desired color, basically what is shown on the can of stain. The other 2 chairs I cannot get to go as dark. I did all of the same prep work on the chairs. I have even tried sanding the other 2 chairs again with a lower grit paper hoping it might absorb more stain but to no avail. I've put so many layers of stain on them and obviously they can no longer absorb anymore. I have also tried tinting some polyurethane with the stain and it really didn't do much of anything to darken it (I messed with the ratios of stain to poly, also didn't give any results). I went out and bought some of that polytint stuff, also really hasn't darkened it quite that much.
I'm not sure what to do at this point. Maybe I should have used a dye instead of a stain to begin with? I know there are gel stains but I have also tried that and thought it looked awful. Any suggestions would be greatly appreciated!!