Monday, March 1, 2021

How to Measure Resin - And Get it Right!

Should you measure resin in ONE SINGLE CUP or TWO SEPARATE CUPS? 

That is a good question!

If you've ever had a batch of resin that stayed a bit soft, even after days of curing, there's a good chance that you didn't get the measurements right. Measuring resin accurately is absolutely essential for it to cure hard. 

So, how can you make sure that you get the measurements correct so that your next resin project cures properly?

And, that you don't end up with some of Part A or Part B left over when you get to the bottom of your resin kit... 

Two almost empty bottles of resin and hardener. The hardener has more left in the bottom than the resin does.
Because there's nothing worse than WASTING resin!

Well, if your resin kit tells you to MEASURE THE RESIN BY VOLUME, then read on!
Different sized plastic measuring cup with graduated measurements

When measuring resin by volume, there are two ways you can do it: 
  • Measure in a single cup; or
  • Measure in two separate cups.

So let's take a look at each of them and see how they stack up against each other.

For simplicity, I'm using a 1:1 ratio resin.

Of course, before you can begin, you need to know how much resin to mix for your project. Once you've worked that out, you'll divide that amount by 2 so you know how much resin and how much hardener you'll need to measure out. 

How to Measure Resin Accurately - Using 2 Cups

Plastic measuring cups often have the measurements moulded into the cup rather than printed on them and the numbers can be hard to make out when you're trying to pour resin into them. So grab a permanent marker and place a mark on each cup at the volume you need to measure to
Gloved hands holding two 30ml plastic cups marked with a permanent marker

Pour the resin in one cup and then pour an equal amount of hardener in a second cup. Now place the two cups alongside each other and get down at eye level to check that they are equal. I know you placed the marks at the measurement you need but it's still important to check that you have the same amount of resin in each cup. 
Remember, you don't want to get to the end of your resin kit and have more resin or more hardener left in your resin kit that you'll have to dispose of.
Two graduated measuring cups filled with equal amounts of resin and hardener

When you measure in two cups and do the eye-level check, you know that you got the measurements correct

But there's more to getting the right amount of resin and hardener than just measuring it. This second step is where it can go wrong. You now have to scrape out equal quantities of each part into the mixing cup. Sounds easy enough, right?

Well, not always. With some resin formulas, you'll find that the resin and hardener have two very different viscosities, and it's always harder to scrape out as much of the thicker part as the thinner part, so you'll end up with unequal amounts of resin and hardener if you don't scrape it ALL out. 
Pink plastic wand scraping all the hardener from one cup into the cup with the resin

This is even more critical if you're only mixing a small batch of resin because leaving some of the thicker resin behind in the cup will make a significant difference to the ratio, and that will lead to curing problems.

Measuring Resin in a Single Cup

OK, so we've looked at the challenge you have with measuring in two cups. So does that mean it's better to measure out both the resin and hardener into a single cup? Let's look at the challenges with one cup.

Once again, you'll need to work out the total amount of resin your project needs and then divide that by two. Use a permanent marker to place marks on the measuring cups at each of these two measurements.
A plastic cup with graduated measurements being marked at 7.5mls and 15mls

Now, measure the resin to the first mark. And then pour the hardener up to the second mark.
Cup filled with equal amounts of resin and hardener. The resin is more dense and sits on the bottom of the cup. The cup is in front of the bottles of resin and hardener

Pour slowly when you're measuring to make sure you are accurate. If you get it wrong for either part, it can get difficult to work out how much more you need of the other part. You still need to get down to the resin at eye level to check you've measured correctly but once you're sure you've got the two amounts right, you're ready to mix.

The good thing with this method is that you don't have to worry about scraping out exactly the same amount of each part because you'll mix it in the cup you measured it in. But it all depends on you measuring correctly in the first place. 

Pro tip: If your resin has one part that is more viscous than the other, then pour that into the cup first because it's a lot harder to control how much of that pours out sometimes. If you go over your mark, it will be much easier to work out how much extra you'll need of the thinner component. 

Chart summarising the pros and cons of measuring out the resin in one cup and two cups

So, is one way better than the other?

Not really. As you can see, there are pros and cons with both methods of measuring resin. 
At the end of the day, all you need to do is pay close attention to your measuring and follow the steps for whichever method you choose. 

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Gradient background in sunset colours with assorted plastic measuring cups and bottles of resin. Features the text "Step-by-step, How to measure resin accurately"

Happy Resining!








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