- Hey all, Jordan here
with another quick science hit for you.
This one was highly requested, so we're coming in hot.
It's the dark side of resin.
This one's about yellowing folks.
Why does it happen?
How do we work to prevent it?
Here's the thing, I'm gonna walk you through all of it.
Why things yellow, what we do to prevent it
and what products you should use at what time.
But there's two things we gotta learn first.
We gotta talk about number one, light
and number two, the actual molecular structure of resin.
It's sciency, buckle up, I'm grabbing the whiteboard.
All right, the two things.
First let's talk about light.
Light comes in the form of waves,
just like sound comes in the form of waves, right?
And there are different wavelengths.
The actual frequency of the waves and the actual wavelengths
is what gives us our actual category of light that it is.
As we get closer to the middle though
that's where we suddenly start
to see these other things we've heard of.
Infrared, X-rays at the hospital,
UV light, we're coming back to that one.
But this right here, visible light,
this tiny little sliver amongst all of this,
that's all the light that you can see.
You're looking at me right now in the camera.
You can only see me through this visible light spectrum.
UV light, an invisible light
because it's not within our spectrum
that exists between 10 nanometers,
that's the wavelength and 380 nanometers.
This right here, that's our villain today.
Let's talk about the second thing we need to know.
And that is the structure of the resin molecules themselves.
So two types of resin structures I want you to be aware of.
First aliphatic, second aromatic.
I'm gonna make this really easy.
Aliphatic, linear structures, the chain is straight lines,
so to speak, those are stronger.
You get a lot of aliphatics
in our Clear and Clear Slow products.
Those are our urethane resins.
That's pretty common to have an aliphatic there.
Now aliphatic epoxies do exist,
but they have very limited uses.
There're chemicals involved in there
that make them not so FDA compliant,
not so friendly for your common projects
and their physical properties aren't as good either.
The second type of molecular structure
that we have to talk about is aromatic.
This is what you see most often in epoxies out there.
Almost guaranteed, all the epoxy that you've used
has been aromatic.
Its molecular structure is actually in the form of a ring.
Why do you need to know that?
Well, all you need to know is
that it's a little bit more vulnerable.
All right, I've talked about a lot of stuff, I know that.
Let me recap for two seconds.
Number one, we have UV light
within this spectrum right here, that's full of energy
and that's coming in hot for our resin.
Thing number two is,
most of the epoxies you're using that yellow, are aromatic
which means they're a little bit more vulnerable.
So how does yellowing happen?
Well, I'm gonna spin the board and draw it for you.
(upbeat music)
What color are you guys feeling, blue?
I'm feeling blue, I'm not sad,
I'm just feeling blue, so to speak.
Anyways, let's start by drawing
a real quick aromatic structure.
Now what happens is that UV light, those photons,
at a certain wavelength actually come in
and with all that energy, knock loose one of molecules
and create what we call a free radical.
That free radical being gone, means this ring is broken,
it's breaking down.
That's what we mean when we say UV light actually starts
to break down your resin.
But here's the thing, you're actually used to this.
Your clothes when they're sun fading,
that's this right here too.
When you get a sunburn, that's this as well,
traffic cones when they're all dingy from the sun
and they start to crack, that's the same process here.
UV light's not just intense for resin,
it's intense for, well for everything.
Now that free radical, how does it cause yellowing?
Well, it's all on its own, it's an agent of chaos
and it's looking for something to bond to.
What does it bond to?
Oxygen, it bonds to oxygen within the air.
So if you have UV light that is actually
causing these free radicals within your project
and it's exposed to oxygen, you're gonna get yellowing.
So, if we had no oxygen in the environment
would we still have yellowing?
No, so if I could pour a tumbler in outer space,
let's say, would it yellow,
even though it's in direct contact with the sun's beams?
No, there's no oxygen.
If you want completely non yellowing tumblers,
just pour them in outer space, space tumblers.
To recap, UV rays hit the molecular structure,
cause a free radical.
That free radical bonds with oxygen
and creates a new compound
that actually turns things yellow.
So what do we gotta do?
Well, we gotta get something that bonds with it
that doesn't turn it yellow.
In our Amazing Clear Cast Plus product,
that's our epoxy with UV enhanced stability,
we add something called UV Absorbers.
Now we add UV Absorbers into our resin mixture,
and I'm gonna represent those with a,
I don't know, the letter A's around here.
Now here's what happens with those resin absorbers.
When UV rays come in, cause this free radical,
break those chains, this resin absorber right here
actually gives that carbon something to bond to,
it actually absorbs that carbon molecule.
An absorbed carbon molecule means no yellowing, sweet!
Well, here's the thing.
There's only a finite amount of these absorbers
that you can put in there.
Eventually, all those absorbers
are gonna be partnered with a free radical.
That means they can't absorb any more of those.
So over a long, long period of time,
your project is still gonna yellow if you're using epoxy.
It's honestly a part of the chemistry.
Another thing that can cause yellowing is exotherm,
the heat that's actually generated from the creation
of your actual finished product, from the resin.
That heat, in the curing process,
while those molecules are starting to create those rings,
well they can actually cause free radicals to occur as well,
they bond with oxygen, you get yellow.
That's why if you use a regular, let's say, surface coating
or tabletop epoxy, and you've poured it really thick,
it'll come out yellow.
So what can you really do?
Well, this is an inevitability.
So we're gonna have to deal with this UV breaking down
and yellowing.
So here's what you can do.
First of all, use the right product.
If you need the extra UV stability,
go with Amazing Clear Cast Plus,
it's perfect for those projects that need
a little bit of extra protection from UV rays.
We've covered as much of that spectrum as we can.
And we put as much absorption in there
as possible to make sure your project lasts
as long as humanly possible.
The second thing you can do, mind the exotherm.
If you're pouring a regular epoxy that's not a deep pour
and you're really pushing how much you can pour,
you're gonna end up with yellowing.
So making sure you're using the right product
is a huge part of this.
If you're going deep, use Amazing Deep Pour.
If you need the extra UV stability,
use Amazing Clear Cast Plus,
or if you're just doing a tumbler
that's gonna not see too much sunlight,
Amazing Clear Cast is the way to go.
The last thing, is color theory.
If you have a white tumbler or a white canvas
or a white project of any kind, well
that's gonna show yellow for sure.
Just because that white is a perfect canvas to show it on.
If you have, let's say a black project
or a dark blue project or another color,
well that yellow is not gonna show up nearly as quickly
even though it's creating the same free radicals
and causing the same yellowing.
So using color theory to your advantage
is another huge thing.
So there you go.
That's an overview of yellowing that you can share
with your friends or answer a bunch of questions
for people who maybe keep nagging you
about why their project's turning yellow.
And let us know if you have other ideas
or other topics you want me to cover.
And get in on the ground floor
on the whole space tumblers gig.
Otherwise someone else is gonna beat you to the punch.
Until next time.
(upbeat music)