How to measure and mix epoxy resin and hardener in five easy steps

How to measure and mix epoxy resin and hardenerEpoxy resin comes as a two-part system:  the Part A resin and the Part B hardener (also known as a catalyst).  Knowing how to measure and mix epoxy resin and hardener is important to make sure your resin cures as expected!  Here are the steps to make sure you have resin curing success every time.

Step 1

Clearly understand the mixing directions of the epoxy resin you are using.  Not all resins mix the same! 

resin mixing instructions

It’s important to note several things when mixing epoxy resin and hardener:

*Does it mix equal parts A and B or does it mix two parts A to one Part B (or perhaps even something else)?
*Does it mix by weight, volume, or either?
*What are the minimum and maximum mixing amounts of the resin?

These resin mixing instructions are important to make sure you get the resin curing results you want.

For the resins sold on Resin Obsession, you can find all that information in this article:  Resin casting kit choices

Step 2

Determine the total volume of mixed resin you need for your project.  From there, break it down into the amount of Part A resin and Part B hardener you need to mix together.

For example, let’s say you are working with a resin mold that needs 1 1/2 ounces of resin and you are using the Resin Obsession super clear resin.  This resin mixes 2 parts A to 1 part B by volume, so you will need 1 ounce of Part A and 1/2 ounce of Part B.

Not sure how much resin and hardener you need to mix?  Here’s how you figure out how much epoxy resin you need to mix for a project.

Step 3

Gather the resin supplies necessary to make sure you get accurate measurements on your epoxy resin and hardener.  Make sure your resin work area, along with your epoxy resin and hardener, are at the ideal temperature.  You can learn more about that here:  What is the best temperature for working with resin?

resin mixing cups

One ounce and ten ounce graduated mixing cups are an easy way to accurately measure your resin kit components.



Pro tip:  You may see other people using their resin kit lid caps, plastic drinking cups, kitchen spoons and other miscellaneous items to measure their resin.  I’m sure that works — at least part of the time.  When I’m troubleshooting resin curing problems, oftentimes it comes down to someone not measuring their resin kit components accurately.  The best way you can do that is with graduated measuring cups designed for epoxy resin.

Of course, we can’t ignore resin safety here either.  At a minimum, you need to wear gloves and work in a well-ventilated area.  You can get my other resin safety tips here:  how to use epoxy resin safely.


Step 4

Now it’s time to pour your resin and hardener into separate cups.  Measure exactly and resist the urge to add extra hardener.  Doing this makes your resin heat up too quickly and shortens the pot time of your resin.

measuring epoxy resin and hardener into graduated resin mixing cups

Pro tip:  Why use separate cups for the two components?  In case I overpour either the epoxy resin or the hardener, I can pour it back into its respective bottle and not waste it.

My other pro tip:  Pour from one bottle, then recap before pouring from the other bottle.  If you uncap both bottles at once, you risk switching the lids.  You don’t want to cure your bottles of epoxy resin and hardener shut.

Step 5

Pour the two parts together and stir well.  Scrape the sides of the cups and your resin stirring stick several times during the process.

You will likely notice your resin having a wavy appearance when first mixing the two parts.  This is normal.  The mix should go clear when you are done combining.

Here’s an example:

waves in epoxy resin and hardener

This is what the Resin Obsession super clear resin looks like after mixing the resin and hardener for about 15 seconds.

clear epoxy resin - Resin Obsession

This is what it looks like after stirring for two and a half minutes.

Pro tip:  My rule is to mix the resin for ten percent of the resin’s pot time.  If I’m working with a resin with a thirty-minute pot time, that means I will mix the resin and hardener together for three minutes.

If you like to reuse your resin supplies, then you will love that you can clean your resin mixing cups for another use.  Here’s how:

Note:  While it’s always best to stir your resin in a way to prevent bubbles, sometimes it is unavoidable, especially if mixing large volumes.  It is always better to thoroughly mix your resin and remove bubbles later with a heat gun rather than undermixing to avoid bubbles.  Undermixed resin will not cure.

Now you are ready to use your resin!

Cast as desired and wait for your awesome resin project to come to life!

And one more pro tip:  Once you start this process, set a timer.  It is a great reminder to focus on what you are doing and not lose track of time.  You want to get all your resin used before it starts to cure!

Here’s how to measure and mix epoxy resin and hardener for resin jewelry, crafts, and resin art purposes in under three minutes:

What other questions do you have about how to measure and mix epoxy resin and hardener?

Want to get to resin expert status quickly?  Then be sure to buy your copy of Resin Fundamentals.  This downloadable book has everything you need to know to get you from confused to confident with resin in a couple of hours!


Unpublished Blog Posts of Resin Obsession, LLC © 2021 Resin Obsession, LLC

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47 thoughts on “How to measure and mix epoxy resin and hardener in five easy steps

  1. If I am putting pieces of brick in my resin do I need to do anything to the brick first? I just usually spread the pieces around in the mold and then put a laminated picture on top of brick and resin!! Then I pour more resin over the picture and brick! Is this the best way! Then I take a torch gun and try and get most of the bubbles out! Then let cure for a day and a half!!! Sometime coasters are sticky!!! Any suggestions????

    1. My resin hasn’t cured and it’s been five days, my other batches have cured in three. How can I fix this?

  2. I find measuring by volume open to mistakes, especially when doing small projects, is it possible to use by weight instead, I use Clear Cast. Thanks ,Julian

    1. Hi Julian, I haven’t used that brand. You will need to ask them if measuring by weight is appropriate for what you want to do.

  3. I’m unclear as to the amt you can mix. The instructions say minimum of 15 ml. What’s the maximum? I have projects like ash trays and pencil holders as well as coasters. Working on insect blocks. I get about half that are successful. I use your resin obsession crystal clear resin

  4. How much in (ml) is measured when using scales? Resin and hardener seems different in liquid form. Is the harderner or resin heavier than the other??

    1. Scales measure by weight, not by volume. You are correct in that one component is likely heavier than the other. The manufacturer of the specific resin you are using should be able to give you this specific information.

  5. Hi Katherine, so I’m facing a small issue. Let’s say that I want to make 4oz of epoxy. Now the epoxy instructions say that I need 2.7 Part A to 1 Part B by Volume. I am not sure how to obtain the specific quantities I need perhaps you could tell me the values if possible .Please let me know.Thanks

    1. Hi Sammy, to make sure you get the best advice possible, this sounds like something you should reach out to the manufacturer for help with.

      1. I tried but nobody ever got back to me.I’m a little upset and confused that’s why I researched the ups and downs until I discovered your website which has fantastic information. Katherine please help me out if you can because this 2.7:1 has me really confused.Thanks

        1. Hi Sammy, I think this situation is best suited for a one-on-one consulting call where you and I talk back and forth about what’s going on. A 15-minute consultation call is $20. I do them by video so I can have a chance to see what you are working on. If you are interested, please send a message through the ‘contact us’ page and I can get this going for you.

          1. Measure out 2.7 of A and 1 of B. Weigh in oz, net weight, this gives you X ox.
            You need 4 oz, so divide 4 by X, this gives Y. All you need to do now is multiply Y by 2.7 Mix A, and Y by 1 Mix B. This gives 4 oz of mixed resin. Dividing Y by 4 gives you unit for multiplying and future differing amounts.

  6. I always see people mixing resin with wooden stir sticks. Doesn’t the wood introduce bubbles into the resin because of it being porous, or are they sealed?

    1. Hi Mundi, every resin is different. You will need to refer to the specific instructions included with your resin kit.

  7. When I use resin color should I use clear resin to mix or the resin color have already been mixed with resin ?

  8. Why do you show a picture someone messing with sticky resin, with no protection on their hands ????????

    1. Hi Allyson, we always recommend wearing gloves when working with resin that hasn’t fully cured. We have several safety articles about resin here: . I believe you are referring to the stock image we have for a different article to give an instant visual impression of stickiness. I can assure you the person was not using resin when the picture was taken.

      1. What do you have to do if you need to add more resin to the project? Do you have to wait till it thoroughly dry’s? Etc.

        1. Hi Diane, you can wait until it fully dries, but you can apply the next layer once the previous layer has started to gel.

  9. Hi Katherine, I’m Philip. I’m very new to this resin crafting art. But I’m addicted already.! My question is about two part molds, the ones where there’s a top that fits onto the bottom making a 3-d piece. What are some tips & tricks to filling it full without getting tons of bubbles & spilling all over from what oozes out between the two pieces? Thank you for your time, Sincerely, Philip P

    1. Hi Philip, welcome to the world of resin! Are you using tape to hold the two pieces of your mold together? That should help with leakage.

  10. Hi there. I’m new to resin. I’m trying to take shopping bags and creat designer acrylic trays. I’m having a hard time figuring out how once I coat the paper. Ag cutting with mod Podge, how do I attach it to the acrylic serving tray before I cover it in resin? I feel like I don’t have to glue it down before I add the resin but no sure? Most cases when I try to use mod Podge to glue down the coated paper to the acrylic, it forms bubbles. So you then see bubbles under the paper after I pour on the resin?! Any ideas ? Should I not try to glue Down the coated shopping bag?

    1. Hi Tina, You have a lot going on here!

      I want to help you with your project, and I think this situation is best suited for a one-on-one consulting call where you and I talk back and forth about what’s going on. A 15-minute consultation call is $20. I do them by video so I can have a chance to see what you are working on. If you are interested, please send a message through the ‘contact us’ page and I can get this going for you.

  11. This is the first time I’m using proxy and resin it’s a big job. It’s cedar boards with crevices that I have sanded down. I plan on putting some color in the crevices do I have to wait for the color to cure before I add the clear? Is there anything I need to do to prep the cedar? When I go to nail it on the wall will it crack the proxy?

    1. Hi Suzanne, you have a lot going on here! I want to help you with your project, and I think this situation is best suited for a one-on-one consulting call where you and I talk back and forth about what’s going on. A 15-minute consultation call is $20. I do them by video so I can have a chance to see what you are working on.

      If you are interested, please send a message through the ‘contact us’ page and I can get this going for you. Sincerely, Katherine @ Resin Obsession

  12. Hello, I have some resin that is 2:1 I’ve never used 2:1 before only 1:1. I know with 1:1 I need 4oz of mixed resin for my project. Now how on earth do I convert that to 2:1… please help I’m so confused

    1. Hi Sarah, you will want to multiply 4 ounces by 2/3 to get the amount of Part A to add. Then multiply 4 ounces by 1/3 to get the amount of Part B. My math says you need 2.67 ounces of Part A and 1.33 ounces of Part B. Does that help?

  13. I am using a epoxy 2:1. I have tried countless times of measuring perfectly and the right room temperature however my resin is leaving a swirly cloud on top when set. What is this due to? I can’t seem to figure it out!
    Thank you

  14. if I use a glass measuring cup to mix 1 and 2 will I be able to remove the left over from the cup when it has cured?

    1. Hi Wendy, I don’t think it will. If you use a glass measuring cup, wipe it clean before the resin cures.

  15. For me it doesn’t make sense at all to weigh resin with a scale, it should be done by volume because it is a liquid. Not by weight, it’s basic science, one is heavier than the other so this method won’t work. Liquids are measured by volume.

  16. hello, my mix still stays a bit cloudy , has some streaks and a few bubbles after i have been mixing for about 3/4 minutes
    what can i do to make it completely clear?
    i have put mix in warm water, also let it sit after i am done mixing, it doesnt fully work, should i keep mixing more til fully clear ?

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