Hydro dipping or water transfer printing is a remarkably simple process in concept and easy to do but technique appears to be the differentiator between great results and mediocre results but there is a limited obstacle to entry and learning to do it well could yield some really great results for finishing your 3D prints. I am going to do a quick introductory guide to finishing your parts using this technique.
What you will need:
A DIY Dip Kit is a good starting point as it includes almost everything you need to get started.
Getting your part ready to dip:
Remove any supports from your part and thoroughly sand to a smooth finish. (Sign up for my newsletter to get my free finishing guide). Once you have your part to the desired smoothness, clean your part with alcohol wipes or a lightly damp cloth.
Primer and Base Coat:
Once your part has dried completely, spray the part lightly with primer to avoid uneven areas or pooling/dripping of the primer. You may need to do 2 coats to get good coverage (15-20 minutes between coats). Once the primer has had some time to dry, spray light and even coats of paint, again you may need 2 coats to get good even coverage (20-30 minutes between coats).
*Depending on your film, different colors of base coat may affect the final look of your part. Using a more transparent film will yield more dramatic effects. Experiment to find something you really like. When buying a dip kit, you can typically manually choose the base coat color or you can have the company provide a recommended color based on your film.
Cutting and Preparing Film:
Cut your film in a size that will be able to fit into your container as well as fully cover the surface area of your object. Review the instructions of the film to determine which side gets placed in the water. I like to use painters tape and tape around the border on the back side of the film as this helps it float and not allow water to run on top of the film. Having your film ready before getting the water to temperature will save you from having it cool down too quickly before dipping.
Preparing Dip Container for Dipping:
For the films, I have seen they are typically 20” wide so my recommendation is to get a container slightly wider than this and then as deep as you feel necessary based on the size of prints you make.
Fill up your container with warm tap water and allow it to settle. You can optionally use a tank heater or something similar to heat your temperature up precisely however dipping has a range it works well with so it’s not critical. Fill with water almost all the way up. You will submerge your parts so don’t fill all the way – leave some room 2-3 inches from the top.
Take your cut piece of film by the corners and very slowly lay your film in the container by starting by dropping the middle slightly into the container and then laying down the sides. Make sure you do this very slowly to avoid 1) creating any bubbles and 2) allowing the water to get on top of the film.
Once your film is set in the container, let it sit for about 1 minute. After this is complete spray the film entirely in slow, light, and even coats with the activator. Spray light horizontal strokes and then light vertical strokes. The activator only needs about 15 seconds to work so be ready to dip your part soon after this is complete.
Hold your object at about a 45-degree angle and dip slowly into the film. Maintain the angle while dipping or roll your object depending on what it is but rolling may cause some distortion in the image transfer. Once your object has been submerged completely, swirl it around under water. Remove from container.
You will need to remove any remaining residue from the activator by rinsing under warm tap/running water (low pressure).
Allow your part to fully dry. Once dry, apply light even coats of clear coat. You may want to apply 2-3 coats.