Mixing Epoxy by Weight

Mixing epoxy by weight is an accurate way to help ensure proper curing and performance. When measuring by weight instead of by volume, it is important to use the correct resin-to-hardener ratio for the specific epoxy system you are using. Those numbers can be found in the chart below or on the product's technical data sheet.

TotalBoat epoxy weight mixing ratios

How to mix epoxy by weight

When mixing epoxy by weight, always use the product specific resin to hardener ratio. Because the resin and hardener can have different densities, the correct weight ratio is often different from the mix ratio by volume.

For TotalBoat TableTop Epoxy, the mix ratio by weight is 120A:100B. That means for every 120 parts resin, you need 100 parts hardener by weight.

To calculate how much resin and hardener you need for a batch, add both parts of the ratio together, then divide the total mixed weight proportionally.

For TotalBoat TableTop Epoxy, the total parts are 220:

• Resin portion = 120 ÷ 220 of the total mixed weight
• Hardener portion = 100 ÷ 220 of the total mixed weight

Example: To mix 120 ounces total of TotalBoat TableTop Epoxy at 120A:100B by weight:

• Resin: 120 × (120 ÷ 220) = 65.45 ounces
• Hardener: 120 × (100 ÷ 220) = 54.55 ounces

So, to make 120 ounces of mixed epoxy, weigh out 65.45 ounces of resin and 54.55 ounces of hardener.

1. Place a clean mixing container on a digital scale.
2. Reset the scale to zero.
3. Add 65.45 ounces of resin.
4. Reset the scale to zero again if desired, or continue weighing carefully.
5. Add 54.55 ounces of hardener.
6. Mix thoroughly, scraping the sides and bottom of the container as you stir.
7. Continue mixing until the epoxy is completely blended and streak-free.

For best results, use a digital scale that measures accurately, double-check your math before mixing, and only prepare as much epoxy as you can use within the product’s working time.

This will work if you know the total weight of the mixture you want to make. If you'd like to figure out how much to mix by weight and only know the total volume(IE Liquid ounces) then please use this Calculator: Totalboat Mixing epoxy by Weight Calculator

If you need help determining how much epoxy your project requires before mixing, use the TotalBoat Epoxy Calculator.

Tips for accurate epoxy mixing

• Use a digital scale that measures accurately in grams or ounces.
• Always confirm you are using the correct weight ratio for the specific epoxy system and hardener speed.
• Mix in a clean container large enough to allow thorough blending.
• Scrape the sides and bottom of the cup while mixing to avoid unmixed material.
• Only mix the amount you can apply within the product’s working time.

Common mistakes to avoid

• Using a volume ratio instead of the correct weight ratio.
• Using the wrong hardener ratio for the specific epoxy system.
• Failing to Reset the scale to zero before adding materials.
• Not mixing long enough or thoroughly enough.
• Mixing more epoxy than can be used within the working time.

Frequently asked questions

Can epoxy be mixed by weight instead of by volume?

Yes, epoxy can be mixed by weight, but you must use the correct weight ratio for the specific product. Weight and volume ratios are often different because resin and hardener have different densities.

Why are epoxy weight ratios different from volume ratios?

Weight ratios differ from volume ratios because the resin and hardener do not always weigh the same per unit of volume. That is why it is important to follow the product-specific weight ratio.

What happens if the epoxy ratio is off?

If the resin and hardener are not mixed in the proper ratio, the epoxy may not cure correctly. This can lead to soft, sticky, brittle, or underperforming results.