This typically happens when you apply too much rubber at once. To ensure success when making a brush-on mold, it is crucial to apply the rubber in very thin layers, especially the first layer.
Here are some tips to help you with your application:
1.Avoid Over-Applying: Applying excessive rubber onto the model’s surface can cause it to sag or run off. It’s important not to waste valuable rubber by overdoing it.
2.Air Entrapment: Brushable rubbers, like pourable ones, need to de-air themselves. Over-applying rubber can lead to air entrapment, resulting in visible air bubbles in the cured mold and any castings produced from it.
3.Proper Application: When applying the rubber, especially the critical first layer, use a stiff paint brush and apply a thin layer over the model’s surface. Start from the top of the model and work your way down, using a “stippling” motion to work the rubber into deep detail.
4.Mixing: Mix only a small amount of rubber at a time. If you mix more than you can apply in 15 minutes, the remaining rubber in the container may become unusable. You can always mix more as needed during the mold-making process.
5.Colorant: Adding a small amount of colorant to every other layer can help you track your progress and ensure thorough coverage.
By following these tips and applying the rubber in thin, controlled layers, you can create a bubble-free mold successfully. Remember that subsequent layers (2, 3, 4, etc.) can be applied with slightly more material, but be cautious not to overdo it.
