How To: Dye Nylon 3D Prints

Not very long ago, nylon was available in only a couple colors: black, natural, and if you’re lucky, white. Now, you can get nylon in a variety of colors in our PRO Series Nylon, like red, orange, green, blue, white, gray, or black. While there are certainly more options to choose from, there aren’t nearly as many colors when compared to filament like PLA, ABS, or PETG. What are you supposed to do if you need a printed part with the strength, flexibility, and durability of nylon, but you need a color that you’ve only been able to find in PLA? Simple, dye it! Dyeing plastics is really easy and is something I’ve been doing for years for cosplay.

Finding a dye is an easy process; you can probably even find them at your local grocery store. The two brands you want to keep an eye out for are iDye Poly (has to be Poly since that’s specifically designed for nylon fabrics and acetates) and Rit DyeMore (DyeMore is also specifically formulated for synthetic fabrics). iDye Poly is available in 16 different colors, and Rit DyeMore is available in 12, so there is a variety of colors, and then you can mix colors from there. I’m going to use Rit “Racing Red” and mix it with "Sapphire Blue” to get closer to a crimson color.

There are two different ways you can go about dyeing your material: you can dye the filament before you print it, or you can dye your part. I recommend dyeing your nylon 3D print rather than your filament, so this article will be about that method. I will explain later the reason why you shouldn't dye your filament. On with the project!

A Lesson on Nylon and Water

Even though your print will be submerged in water, being hygroscopic isn’t a problem. Being hygroscopic is only a problem if the nylon is heated to glass transition temperature, because what happens is wet nylon that’s been heated has its molecular chains break down and be filled with water molecules, thereby making a weaker bond and a weaker print. Boiling water isn’t hot enough to break those chains, and the water it absorbs won’t affect its structural integrity either.

Method 1: Dying Your Finished Nylon Printed Part

As I mentioned before, we'd be focusing on dying a Nylon part after it's been printed - here is everything you need to know! 

Gather Materials and Equipment for Dyeing Nylon Prints

You will need:

• Dye colors of your choice
• Nylon 3D Prints
• A container deep enough for your print, and you don’t mind dyeing it.
• Second container to rinse dyed 3D print
• Thermometer
• Water
• Mixing utensil
  
• Pliers or tongs
• Timer

Optional:

• Wire to hang 3D print
• Weight to keep 3D print submerged.

Step 1: Drying Nylon Filament

If you’ve ever printed with nylon, you know it’s hygroscopic. If you haven’t, what that means is nylon readily absorbs water from the air, and if we’ve just had it submerged in a bath of water, it’s going to be really wet. Before doing any nylon prints, you always want to make sure that your nylon has been dried.To dry it, set your oven to 180 degrees Fahrenheit (not Celsius!), making sure to allow your oven to preheat before putting your filament in. Leave in the oven for 4 to 6 hours. After it’s done baking, immediately print with it or store in a container with desiccant until you are ready to print. We have a vacuum oven to rapidly dry filament within half an hour. Another option is to use a PrintDry to dry the nylon, keep it dry, and print straight from it.

Step 2: Prepare your 3D prints.

Depending on how long you leave your 3D print in the dyed water will affect the concentration of color in the final print. Print 5 small test prints (either small Phils, test cubes, or whatever you'd like) so you can test what time you like best. I printed out 5 of these MatterHackers swatches, and left them in for varying amounts of time. Five minutes looked dark enough but not too dark, so that's how long I would be dyeing the Phil I printed. 

Note: Make sure to clean off any PVA glue or hairspray from the bottom of your print, otherwise anywhere there's glue the dye won't take as strongly.

Step 3: Prepare the Dye Solution

Take the container you are going to be dyeing in and fill it with water. Be sure to leave enough room from the top for the 3D print (and a weight if necessary) to displace and not spill over. Depending on the color you want to create, you may need to add more or less dye. For my crimson mix, I used about half the bottle of red and a quick spurt of blue. In your other container, fill it with cold water. This container will be used to quickly cool the filament and “lock in” the color.

Step 4: Dyeing the Nylon 3D Print

Preferably, use a hotplate outside to dye your filament, so you don’t dye the ceiling in your workspace with dyed steam. Heat up the water to about 140° Fahrenheit, and keep an eye on the thermometer. You will need to turn off the heat before it reaches 140°, because the water holds temperature really well and even if you turn it off when it reads 140°F, it could reach as high as 160° before it starts to cool down (like it did for me). When it's at a temperature you're satisfied with, gently lower your test prints into the water. You need to see how much dye is enough, how long to get the right color intensity, do you need more of dye A or B, etc. Once you’ve found the sweet spot, place in your 3D print and start your timer. If you don’t get all of it submerged, your prints will come out striped or splotchy. This could have an interesting effect if done intentionally, otherwise submerging it will ensure your entire print is one uniform color. When the timer has stopped, remove it and dunk it in the second container.

Method 2: Dyeing Nylon Filament Before Printing

This method is much more difficult since you need to put the filament in without a wire, weight, or anything touching it since those spots won't take dye as strongly as the rest of the filament, if at all. Not only that, but you have to unspool the filament and hope you have enough or don't have a print failure using up your dyed filament. If you choose to dye your filament though, there isn't much you have to do differently. All you have to do is dye the nylon, dry it in an oven after following the same steps as before, and printing with it as normal.

And that’s all there is to it. It’s very wordy, but dyeing nylon is just as easy as boiling pasta. With this information you can create nylon 3D prints in colors exclusive to you and your work, so get started dyeing nylon. I’d love to see what unique colors you can blend and 3D print.

Is there something you'd like to see Alec create using 3D printing? Let us know in the comments below, or send an email to support@matterhackers.com.