There are two common mistakes people make when working with epoxy resin. The first is incomplete mixing and the second is inaccurate measuring. If the mixing and measuring are not done correctly it can cause improper curing or weak spots. Mixing and measuring accurately are especially important when working with a two-part epoxy resin. Measuring can be slightly forgiving when working with polyester resin but with epoxy it is imperative that it is done right.
Read the manufacturer’s instructions carefully and make sure you know the mix ratio. Epoxy resins come in various ratios including 1:1, 2:1 and 4:1. Some are measured by weight and others are by volume. If it is by weight, use a small scale to ensure it is done correctly.
When mixing resin, you should change containers during the process to ensure a complete mix. For example, measure out the hardener in cup “A” and the resin in cup “B”. Pour the hardener from cup “A” into cup “B” with the resin and mix really well. Make sure you scrape down the sides as you mix. Then pour the mixture into cup “A” and repeat the process making sure the sides are scraped down. You could repeat this process again by pouring into even another cup. This may seem like overkill but an incomplete mix can ruin your part. It is best to take the time to mix thoroughly before delving into your project.
If you follow these two steps you will be starting your project off on the right foot. Try a test batch and experiment before getting into your project. Working with resin is an art not a science.