With all that Rit-dyeing going on and no easy source for that stuff in Europe I went to look for alternatives. Dylon universal dye or multi-purpose dye as it is also called, seemed to be ok for key caps as it is suitable for dyeing nylon, lycra and buttons. And it's generally available where I live (The Netherlands) but also in the UK and Germany and probably in more countries.
It comes in various package sizes and I found a few mini tins of 4.5 g each at a local craftshop.



A set of PBT caps (nearly-white and light grey) of a Cherry MY board (G81-3504LAAEU) was picked as victim along with a few caps of an IBM model M.




I found an old aluminum camping pan to perform this experiment in. Note: aluminium pans are not the best choice, see conclusions & recommendations.
The general procedure was as follows:
*The dye (4.5 g) was dissolved in 700 mL of boiling tap water
*The heat source was removed and 30 g of table salt was added whilst stirring until completely dissolved
*The pan was put on a simmering plate and the keycaps were added
*The mixture was gently stirred for the indicated time while the temperature was kept between 60 - 80 °C (estimated)
*After the dyeing process, the caps were washed with warm tap water and soap

1st round:
Dylon No 25: Emerald
An oily film appeared on the surface of the dyeing mixture. Probably some traces of instant-noodles. I should've cleaned the pan more thoroughly Some of the film stuck to the caps causing some uneven coloring. In the end (after 30-35 min) the key caps came out OK but the space bar clearly shows some darker regions.
The result is caps with quite a light green color on the near-white caps and a forest, almost military green on the grey caps. Scroll down for pictures of the result.



2nd round:
Dylon No 19: Deep Blue
The pan was thoroughly cleaned with an oven cleaning agent ("Muscle" brand) and some iPrOH. The caps were rinsed with iPrOH. No oily skin on the mixture this time.
Blue surprised me: The caps nearly went otaku within 10 min, that's how well they absorbed the dye. The near-white and the light grey caps came out looking nearly the same.



3rd round:
Dylon No 10: Cherry Flame (couldn't resist)
Pan cleaned with oven-cleaner, this stuff also removed dye residues. Caps rinsed with iPrOH.
This dye bath became a bit flaky over time but the dyeing process went really well. After 40 min of simmering I had some nice, red caps. They darkened a bit on drying.



4th round:
Dylon No 2: Golden Glow
Again in a clean pan with clean caps: As an experiment, the salt was added after the key caps in two equal portions. On adding the salt, some of the dye precipitated (that's probably one of the functions of the salt).
Something went wrong in this run. The caps immediately got some specks of concentrated dye on them; those did not fade during 50 min of simmering. Could be due to the late addition of salt but I really suspect that the dye wasn't completely dissolved before I threw in the caps.
Afterwards, the caps darkened a bit on drying, and now they look more gold-brown than yellow, especially the ones that were grey before. Well, the dye is called golden glow after all. These are the only dyed caps that I'm unhappy with mainly due to the ugly specks and stains.

Results:
Look at all these funky colors on top of some squishy MY switches! and those 4 model M caps! I'm rather pleased in general, only the failed yellows are a pity.




Here's the most important picture, a key matrix


Some problem zones: The dye is rather sensitive for irregularities in the plastic. The injection points of the caps take up the dye worse than other parts. One of the IBM caps has some smears of lighter color on it. I don't know if this is caused by the plastic structure or if this cap was a bit dirty.
The sides of the IBM caps were sligthly warped but they still fit very well on their stems. Only tighter than before.



Conclusions & recommendations:
*Dyeing PBT caps with Dylon universal / multi-purpose dye works.
*The color doesn't rub off. No blue fingers so far.
*The Cherry caps keep their shape while the IBM M caps are slightly bent inwards. Don't be alarmed, they still fit on their stems very well.
*Some dyes obviously are absorbed better than others.
*Clean and degrease your pan! And your caps!!
*Dissolve the dye completely before adding the caps.
*Aluminium pans are generally a bad choice as this metal corrodes in acid or basic aqueous solutions.
*Quite some dye stuck to my pan due to its rough surface which made cleaning very difficult. I suggest using a smooth stainless steel pan or even better an enamel pan or a large glass beaker.
*I'm still not sure if the salt is necessary for dyeing key caps but it won't hurt to add it. BTW, it is absolutely necessary when dyeing textiles.

Future plans:
*The dye solutions were a bit heterogeneous. Next time I will try a larger volume (1 L water) and less salt (10 g). I'll also experiment with acetic acid as mordant instead of salt. All that will be done in a non-aluminum pan.
*I need to get a thermometer...
*Dylon multi-purpose dye, just as Rit dye, is a mixture of components: It consists of a reactive dye for cotton and rayon (probably useless for key caps), further an "acid dye" component for nylon and wool and possibly also a dispersion dye. I think it's the latter two that do the trick for the caps. It could be worthwhile to look for a source of pure acid dyes or disperse dyes that are designed for polyesters. Technically spoken, PBT is a polyester but it's rather different from the most common polyester, PET (polyethylene terephthalate) PET is the raw material for polyester textiles like your fleece sweater but also for soft drink bottles. My guess is that you can color PBT with dyes that are not able to penetrate PET.

Sources & links:
*Dylon multi-purpose dye (Dutch site): http://www.dylon.nl/products/verven/multi-purpose-tins/
*Dylon (English site, only shows the large 500 g tins): http://www.dylon.co.uk/product.php?alias=industrial-products&products=product-info&alias-product=multi-purpose-dye-500g
*A great site about dyeing, lots of information: http://www.pburch.net/dyeing.shtml
*About Rit and Dylon multi-purpos dyes: http://uk.answers.yahoo.com/question/index?qid=20080603125016AAkeooD
*Geekhack example of dyeing Model M caps with Rit: http://geekhack.org/showwiki.php?title=Island:15277

edit: removed some macabre typos

Wow... Great research! Thoroughly analyzed...

awesome work.. !
ps. would you say that darker colors (blue,red)work better than lighter ones(yellow, green)
ps2. if you want to try (and post here) some doubleshot cherrys i'd send a set with your order

Awesome job! Its time now to take orders and keep cooking keycaps (I'd pay for such job )

Kijk, dat is nou nog eens goed nieuws! Ik ga dit zeker ook proberen

I totally love the deep blue, that's really awesome work !

Thanks guys for your kind praise.

mintberryminuscrunch wrote:awesome work.. !
ps. would you say that darker colors (blue,red)work better than lighter ones(yellow, green)

I guess so. But I'm afraid that it's not that straightforward. Most of the dyes are composed of different colors. Golden yellow for instance had some red in it and the deep blue some green. It's more than likely that one of those dyes "bites" better than others leading to a different shade than the color shown on the package. That's what probably happened with emerald (green) and golden yellow. Can't blame Dylon, their products were designed for textile.

mintberryminuscrunch wrote:ps2. if you want to try (and post here) some doubleshot cherrys i'd send a set with your order

Mmh, afaik double shots are always made out of ABS. That's a very hard material to dye. I've found this forum post about dyeing ABS with Rit in a water/acetone mixture.
http://twistypuzzles.com/forum/viewtopi ... 9&p=277297
No need to try that on double shots immediately, I would take the first steps with ordinary ABS caps. Or LEGO blocks

prava wrote:Awesome job! Its time now to take orders and keep cooking keycaps (I'd pay for such job )

It's time to try it for yourself! Lots of fun guaranteed. Just be sure to clean up the mess in the kitchen or your significant other might not be too impressed with your hobby anymore

btw. is the paint reusable or does some compound dissolve or whatever?

mintberryminuscrunch wrote:btw. is the paint reusable or does some compound dissolve or whatever?

Actually I don't know with the dyes I used. I've read in some dyeing forums about people storing their dye baths for weeks. My brews, however, looked rather heterogeneous (flaky) afterwards. It could be due to me using an aluminium pan; I can imagine that a little of the metal got eaten away and formed some insoluble aluminium salts.

Kurrk where i can get those dye's?

I saw some on ebay but dunno if they will work fine for this.

You prompted me....

Now I'm going to get to the bottom of this

I can't wat to see your results!
The next step obviously is to create a huge database containing all Dylon colors mapped out against different keycap materials and kooking time. We have to do it, for ‼science‼

Well,

I just established you can't just throw PBT caps inside room temperature dyed water plus some acetone and wait for something to happen. It won't.

Now adding another variable : temperature. Wonder what that will do in my setup. ( Although my wife started to look confused when I said I was going to 'boil some caps' )

After that : salt.

Regards.

Mrinterface wrote:You prompted me....

Now I'm going to get to the bottom of this

Hello

Any updates?

glossywhite wrote:Hello

Any updates?

I looked for something cheap to heat up the stuff, but can't find it ( yet ) . My wife won't let me use the regular stove

Just boil clean ol tap-water on the regular stove (wives will let you do that most of the time) and then take the boiled water somewhere else to add the dye and play with it

Thanx for the tip but it will cool too fast I think.

Need to find something so I can keep the temperature of the mixture at a constant level. If I'm going to do this I am going to use the scientific approach. What else would I have this technical degree for?

Well.... how i plan on doing this is quite simple actually; Ill just grab a really really big pan with water (more mass = more stable temperature when adding anything cold) and ill place a glass beaker with the dye solution inside that aka au baine-marie. The beaker will be on a little tripod inside the pan so the water underneath it will not heat up too quickly, making the beaker wobble and pissing me off I can then hang my temperature probe in the clear water to keep an eye on temperature whilst trying different things. I was thinking dipping for short periods near boiling point (to hopefully reach max effect keeping malformation ans shrinkage to a minimum) and cooling in cold salty water and/or leaving it in for longer at lower temperatures.... stuff like that.

I think something similar should be scientific and easy enough to entertain your degree AND it should keep the wife happy as the pan will not get dirty.

Ah, I see you are ahead of me -> you have a temperature probe. I don't even have that one yet.

I already am eating my way through the available pickles to get several glass jars I can put my re-usable dyes in . Got a cheap little pan for them. Now for something to heat it up and something to monitor it to close the loop.

I am still curious to see as to what your results will be with your approach, I'll keep you updated on mine

Well yeah, i even had a real nice mercury filled glass laboratory thermometer but the wife broke it (go figure) so now i have to use my multimeter with a home-built NTC sensor.... Oh well, at least my multimeter has a an option to use one of those.

BTW.An easy way to get caps in and out of the dye is to use a plastic fruit net, like the ones you get when buying oranges etc. And they don't melt!

mintberryminuscrunch wrote:BTW.An easy way to get caps in and out of the dye is to use a plastic fruit net, like the ones you get when buying oranges etc. And they don't melt!

That's an excellent idea! I was looking for something pincer like, but a net like that would be much better.

just looked around nearly everywhere but these tiny dylon capsules are nowhere to find. Any ideas where to get ?

Living in Germany you can order Dylon universal here:
http://www.patin-a.de/pi/Dylon-Universal-Color.html
Apparently they sell 9 g tins which is twice the amount that I've used.
I'm sure that there are other places as well where you can get the dye.

they sell it in zip bags.
it's where i got mine

Awesome!
I'd say they both work quite well (together), the emerald and the dark blue.
and yay for instant noodles <when not on your keys>

Doing this right now xD looks good. will make some pictures since i am doing different colors

Pic1 Color Windsor Purple after roundabout 15minutes
Pic2 Both Windsor Purple and Tangerine (Orange) - Tangerine after nearly 50minutes
Pic3 The Colors

Used about 4g color and 30-40g salt on 400ml water.

And i have to admit, i simply love the windsor purple

Those turned out really nice. How much are those colors?

9gr. each 2,95euro at http://www.patin-a.de

next week i will do a session with Emerald Green and Jungle Green