Resin Casting: Tips and Techniques


"Serving Two Masters" - completed re...

Summary: “Resin Casting: Tips and Techniques” introduces the reader to the concept of plastic casting resins. It explains that two liquid resins are mixed together which then harden into the desired shape. The article offers safety tips and advice on choosing the right resin, then discusses tools, materials and ideas for projects.

Introduction

You can use transparent casting resins to make models, small parts, jewelry and sculptures. Casting resins come in liquid form; they are two-part plastics – a main plastic and a hardener. When you combine the two liquids, they react chemically with each other. The chemical reaction changes them from a liquid to a solid, rigid plastic. This hardening process is called curing.

"The Age of Industry" - completed re...

Safety Tips

When casting resin is completely cured, it is inert and safe to handle; before it’s fully hardened, however, you need to follow some basic safety precautions. Don’t let the resin or the hardener come into contact with your bare skin. All plastic casting resins are irritants. Wear gloves while you’re working with liquid plastic resin, and if you do get any on your skin, wash it off straight away. Until the plastic is hard, it will give off fumes which are also  toxic and irritant. Work in a well-ventilated area and make sure that the lids of the resin containers are tightly fastened. Keep plastic resin away from pets or small children.

Choosing Your Resin

You may find resins formulated for use in repairing fiberglass boats which are cheaper than resins for making small crafts or jewelry, and it’s tempting to try and use these lower-priced resins instead. These resins aren’t really suitable for crafts, however. They are brittle, and even after curing the surface remains sticky. In the case of projects requiring a transparent resin, they have the additional drawbacks of inferior clarity and a tendency to yellow. Epoxy resins that are formulated for crafting have superior clarity and color. They cure with a smooth, shiny surface and require less sanding or polishing.

Resin wound

Specialty Resins

Plastic resin comes in several different varieties. It’s important to select the right one for your project. A basic clear resin is a good choice for embedding small items. To produce color or opacity, blend pigmented resins with the clear resin. Glitter and pearlescent or metallic additives are available which you mix into the resin to create decorative effects. Doming resins are special thick resins that form smooth domed shapes when poured up to the edge of a mold or a hollow jewelry blank. Use these to make cabochons, or exploit the lens effect of the resin dome to make bubble stickers or magnifying pendants and refrigerator magnets.

Mixing

Plastic resin is very difficult to remove so mix your resin using disposable pots and stirrers. Always follow the the manufacturer’s instructions when mixing the resin. The exact proportions of resin and hardener you need to mix vary between different brands and types of resin: some need to be mixed in a 1:1 ratio, while for others you add only a few drops of the hardener to the resin. Only mix up as much resin as you need for your intended project – leftover resin will harden and be wasted.

Casting Jewelry

You can use resin to make make jewelery items. You can mold pieces or pour doming resin directly into hollow pendant and brooch backs called blanks. Use casting resin to make pendants, bangles and brooches. Mix resin in two or more colors to make marbled effects. Place beads, sequins, fabric scraps and other small decorative items in the blank or mold and cover them with transparent resin. These items will remain in the resin permanently, as if floating in clear water.

Molds and Tools

A Baldwin 6-axle locomotive kit cast in resin ...

Unless you are pouring the resin into a permanent container, such as a pendant blank, you will need to mold it. Choose suitable mold materials as some plastics will react with the liquid resin. Good  materials for molds include latex and silicone. Buy ready-made molds, or create your own molds using liquid molding compounds. A sharp knife is useful for trimming away excess resin once a piece has cured. Use fine wet-and-dry sandpaper to smooth any rough areas.

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3 thoughts on “Resin Casting: Tips and Techniques

  1. Pingback: A Guide To Choosing Safe Plastic Toys For Kids | Toy Reviews

  2. Pingback: resin results « Make Something Every Day

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