Dyeing ski boots

We all know that the most important thing in skiing is your gear and the better you look, the faster you go. I didn't like my white Head Raptor 140S RS boots yellowing over time so I decided to dye them.

Formerly white Head ski boots dyed magenta

Dyed boots on the snow

Ingredients

Head Raptor boots
Synthetic fabric dye: iDye Poly or RIT DyeMore.
Dish soap
~30 liters of water

Equipment

Large pot (mine is 40 cm circumference) with enough water to fully submerge the shells (cuffs of the bottom shell can stick out a bit since they are hidden under the top cuff)
Non-metal stirring spoon that's long enough to reach the bottom of the pot
Silicone oven gloves (waterproof & heatproof)
Floor and tables around the stove need to be covered in foil or plastic bags
A digital clock with seconds so you can precisely measure time

⚠️ Cook only outside or in an actively ventilated area, use a high power fume extractor! Just opening the windows is not enough! Remove anything that you use for food from the room. Remove things like curtains and towels as they could absorb fumes.

My cooking area with a DIY fume extractor that ended up being too weak, needed a more powerful fan (mine used 100 mm 12V computer cooler).

Recipe

Disassemble and clean the boots. You should have 2 boot shells and 2 cuffs with no parts attached. Make sure everything is ready before starting.
Wrap one boot shell in a plastic bag and secure with masking tape, leaving only the cuff open. This will be used for testing the cooking time/color. The bag is necessary to prevent the visible parts of the boot from being dyed by vapor and splashes. I didn't do it and I first tested the green dye, the small vapor particles painted the boot (photos below).
Boil the water. It takes a very long time, about 1 hour.
Add some dish soap, I did 10 soap dispenser presses. Not sure if necessary but others say this helps the dye spread more evenly.
Add the dye and the dye intensifier. I added the whole packet of the intensifier but if I were to do it again I would add much less, maybe 1/3 or 1/4 of the packet. Boots absorb the dye very well and less intensifier would mean less fumes and a bit more cooking time so the color is easier to control.
Stir well for several minutes until the dye is fully dissolved.
Test: use a boot sole or cuff of the shell (basically something that isn't gonna be visible in the complete boot) to test the dye. Ideally you want to achieve the color you want in 2-3 minutes. In my case since I added the full packet of dye intensifier the dye was already too strong at 1.5 minutes. Since dye bath is very dark it's hard to see the color you are getting, so you may need to occasionally pull the boot out. Better pull out early than late. If you are happy with the test color, note the time it took and proceed to the full shell dye.
Put both shells into the bath and stir well to get an even finish.
After enough time has passed, pull them out and rinse with warm water.
Repeat the dyeing process with the cuffs.
After everything is done, wash thoroughly with dish soap. Don't worry, the dye won't come off. I put half a bottle of dish soap in a bath tub and scraped thoroughly with a sponge for about 30 minutes. My boots still have a bit of the dye intensifier smell after that so I should've added less of it.

Precautions

Wear safety goggles and a respirator.
If indoors, use a powerful fumes extractor. Mine wasn't powerful at all and I got poisoned a bit (after 1 hour in the fresh air I was ok).
If you have any bootfitting adjustments, you will need to redo them afterwards. By the way hot water seems like a good way to make these adjustments.
Every boot plastic is different and the results may be different from what you expect, so be open for that. If you want a very specific color and that color only, buy a new boot in that color as you will be disappointed with this DIY method. For me almost every color is better than yellowing so I was ok with that.
I don't know if boots are really safe after this procedure so do it at your own risk.
Make a checklist before starting and make sure everything is prepared and done according to this checklist. Don't think that you can hold everything in your head. For example, I completely forgot to test the pink color like I intended and just fully dipped the boots right away. If I did test it, the result would likely be much closer to what I wanted. I'm a bit disappointed with that. But mistakes happen!

Process photos

My boots when I just bought them

Disassembled boot shell showing some yellowing

I tested the green dye first and it splashed the visible parts of the boot

I spent about an hour scraping off the green splashes from the most visible part of the boot using a box knife blade

Dyed bottom shell. I should've used some sandpaper to even out the scratches from the ski edges as they apparently are too glossy for the dye to stick.

Result

Let the boots cool down for at least 12 hours and they are ready to serve on some clean white snow.

The result: magenta boots.

I overcooked them a bit and they turned out magenta rather than pink as I wanted. Too much blue pigment and too dark of a color. What's interesting is that depending on the lighting, the color of the boots looks slightly different, from almost purple to almost pink.

I'm not the biggest fan of the color overall. But it's still better than yellowing white and they will for sure stand out on the slopes and make me a much more advanced skier.