4:1 and 100:55 Ratios (by weight): A Practical Guide

What Do 4:1 and 100:55 Ratios Mean?

These ratios refer to the weight of resin and hardener you should combine. A 4:1 ratio means you use 4 parts resin to 1 part hardener by weight. Similarly, a 100:55 ratio means you mix 100 parts resin with 55 parts hardener. It’s important to measure these components using digital scales for accuracy, rather than by eye or by volume.

How to Accurately Measure and Mix

• Use Digital Scales: Always weigh both resin and hardener before mixing. Zero your scales with the mixing container in place.
• Add Resin First: Pour the required amount of resin.
• Add Hardener: Using the ratio, calculate and add the precise amount of hardener.
• Mix Thoroughly: Stir slowly and deliberately, scraping sides and bottom, until the mixture is uniform and clear. Mixing for a few minutes helps ensure complete reaction.

When to Use Weight-Based Ratios

Weight-based epoxy ratios like 4:1 and 100:55 are most often required for deep pour projects, tabletops, larger castings, and woodworking that need structural stability. For example, EpoxyTable 5-Five is a popular choice for pours up to 5cm thick, and explicitly uses a 100:55 resin to hardener ratio by weight to achieve consistent results.