I've recent seen some really cool videos and images where people are hydro dipping their Yeti tumblers and giving them a cool swirl effect, psychedelic patterns or awesome prints.
I'd never heard of hydro dipping before are there are some basic how to videos on YouTube but I personally wanted to understand the science behind hydro dipping and exactly how hydro dipping works.
Often understanding how something works at a fundamental level can lead to us getting better results when we do it ourselves.
Hydro dipping goes by a bunch of different names:
- immersion printing
- Water transfer printing
- Water marbling
But the premise is still the same:
Hydro dipping works by creating a film-like layer of paint on the surface of water that your object is pushed through. The paint is hydrophobic (oil-like) and designed to permanently stick to objects quickly but not to dissolve in the water. So as an object is pushed through the paint binds to the object.
That's the basics of it, but I had a bunch of questions like how does the paint stick things even though it's wet in water? What's the difference between using spray paint or using hydro graphic prints? Why are activators needed?
So I did a bunch of research, learned a lot and wanted to share in a simple understandable way how hydro dipping works.
You can also check out my step-by-step instructional guide on how to Hydro Dip a Yeti cup (or anything).
How Doesn't The Water Wash Away The Paint?
The biggest question I think I had was “how doesn't the water wash away the paint?” and “how does the paint stick to an item even though it's wet?”
The answer was actually pretty simple.
The paint is hydrophobic – which means it doesn't mix with water.
Think about how when you try to mix oil and water they don't mix, but the oil just sits on the top of the water. The same is true for the paint – both the graphics and the spray paint.
The paint DOES NOT mix with water, but instead we use the surface tension of the water in order to keep the paint or graphic stable as we push our object through it.
The surface tension of the water also helps to pull the paint towards our object as it moves through the paint, giving us an even coating all over.
One of the biggest hydro dipping mistakes is getting water on top of the paint as this stops it adhering correctly to your object.
How Does Paint Stick To Object When Hydro Dipping Even Though It's Wet
Usually when you're painting thing you want to avoid them getting wet because paint doesn't stick well to wet things.
Given hydro dipping is done in water how does the paint stick?
The reason is the top layer of the paint (the layer that connects with your object) isn't wet at all. Underneath is wet but the top is dry and exposed to the air.
Your object also isn't wet, it should be dry before you begin.
As you lower the object through the paint into the water the film of paint sticks to your object before it is submerged.
Even with some water the paint can still stick, it doesn't have to be completely dry to stick onto your object but for the best results it definitely should be.
How Do Hydro Graphics Work?
Hydro graphics usually come on a roll of paper, kind of like wrapping paper which you can cut to size.
On one side of the paper is the ink/paint that will actually attach to your object. This ink/paint is hydrophobic meaning it doesn't dissolve in the water.
One the other side is a thin layer (likely polyvinyl alcohol or PVA) that is soluble in water. This is why it's very important which side you place in the water first because the water soluble side needs to go down first so it can dissolve in the water.
If the water soluble side goes face up it won't get wet and won't dissolve and thus your print won't adhere properly.
So you place the graphic in the water, the water soluble ingredient dissolves in the water leaving just your ink.
You then add what they call an “activator” which is basically a combination of chemicals that acts as a paint thinner and it softens the paint and gives it the ability to stick easily.
This article has some great information about activators and how to make your own if you want to.
How Does Spray Paint on Top of Water Work?
The spray paint on top of the water works in a similar way to the graphics.
Basically as you spray the paint onto the surface of the water the paint is hydrophobic so it doesn't mix with the water but rather sits on top of the water.
The more spray paint you add the thicker the layer of paint on top of the water. Leave it for a bit and the paint connects together on the surface of the water creating a top layer of paint with water underneath.
No activator is needed as the paint is already able to stick to your item.
As you lower your item into the water it passes through the layer of spray paint which adheres to your item painting it in the pattern you created.
This is really easy to do and can give you some really cool effects. But it can also give you a poor quality paint job that isn't smooth if you don't do it properly.
Hydro dipping Is An Amazing Invention
When you think about it hydro dipping is a pretty incredible invention.
A combination of the different properties of water, PVA and hydrophobic paint combines to make it extremely easy to paint complex designs onto 3D objects.
Prior to this I can imagine it would have been nearly impossible to quickly paint these intricate designs onto 3D objects with lots of different angles and curves. Maybe it even had to be hand painted.
However, now it's so easy it can be done at home with some safety gear and it can also be done to larger objects with specialized equipment.
I haven't personally hydro dipped any of my Yeti tumblers yet. But I'm really excited to give it a try.