Substrates for Resin

There are a variety of substrates that you might use to bond resin and glass to. In this page we will focus on polyester resin, and fiberglass, though it's possible to use other resins such as epoxy, urethane, and also other laminates such as carbon fiber or kevlar.

This page will not cover molding type materials such as silicone, or another piece of glass with mold release applied.

Cardboard

This is the simplest material to start with if you are new to glassing. Cardboard is easy to find, and work with, requiring nothing more than a razor blade to shape (with maybe some kind of adhesive). However, cardboard is a flimsy material, and you may have to purchase higher grade cardboard if you want to get better results, rather than working with leftover box material. If you start out with a slightly crooked model, you will have difficulty fixing it down the line, as opposed to working with something like plywood or balsa, where it is rigid enough that it easily keeps form.

Advantages

• Lightweight
• Easy to Work With
• Cheap and readily available

Disadvantages

• Does not hold form well

Balsa Wood

This is a common crafting material. It is used in high schools for creating truss bridges (See: https://www.pitsco.com/ and https://go.pitsco.com/pitsco-bridge-book) where thin balsa rod will be the form factor, in Model Airplane kits (See: https://www.guillow.com/),and also in larger sheets for traditional wood working tasks. It can be used in wood carving as it is reasonably easy to cut (Wood carving books are common and you will find them at libraries, thrift stores, or used book stores. Two I have come across but not read are Classic Whittling by Rick Wiebe and the Beginner's Handbook of Wood Carving by Beiderman and Johnson. I would not recommend any carving without a vice, contrary to what the books show. Balsa seems to be an excellent material for small models, as well as suitable for larger parts. Though it is flammable.

Advantages

• Lightweight
• Easy to Work With
• Reasonably Low Cost

Disadvantages

• Flammable, as all woods are.

Plywood

Plywood is a ubiquitous material for most any construction project. I have not worked with plywood too much as I work on a small scale, but I might use one of the thinner options.

Advantages

• Available at Retail Hardware Stores and Lumberyards
• Feasible to work, with any contemporary tools.

Disadvantages

• Flammable, as all woods are.
• Heavier than Balsa
• Slightly more difficult to work with than Balsa

Foam

There are many kinds of foam available. Foam is its own industry, and there are companies that specialize in this or that type of foam. I have written a bit about working with the most commonly available option here, Polystrene or Styrofoam here.

Foam is a good option for preparing the substrate with CNC, being lightweight, and easy on the CNC cutting mills and drill bits. You can also dissolve foam with citrus based products.

Advantages

• Good material to work with CNC
• Lightweight
• Can cut with resistance wire.

Disadvantages

• Many different options. You have to choose a few to work with, otherwise it will be too much.
• Possibly not as easy to work, with contemporary tools. For example, polystyrene can crumble. (This will depend upon the foam).
• Exothermic resins can melt foam. In this case, cures must be done slowly.

Other Materials

As with bonding to other materials, typically you will want to:

• Prep the surface properly with sanding or grinding.
• Test a small area first

We occasionally test by bonding to parts of scrap metal we have hanging around the shop, but I will make an effort to do some more formal tests and write something here.