Epoxy Basics: How To Thicken Epoxy with Fillers?

What are epoxy fillers?

Epoxy fillers, they’re pretty important. They change the epoxy’s properties to fit what you need. Want more strength or abrasion resistance? Or maybe you need to fill some gaps? Epoxy fillers have you covered.

What types of epoxy fillers are there?

Whether you’re looking to enhance the strength of your epoxy, increase its abrasion resistance, or fill gaps, these fillers are up to the task. They are engineered to transform the epoxy’s inherent properties, making it more versatile and adaptable to your project’s requirements.

Now, when it comes to WEST SYSTEM® Epoxy fillers, you’ve got a few options:

402 Milled Glass Fibre Blend: This is a high-density blended filler. It’s made up of loose chopped glass and other fillers. It’s perfect for small semi-structural repairs, filling voids, or small-scale impact damage to glass fibre laminates.

403 Microfibres: This is a fine fibre blend. It’s perfect for when you need to thicken your epoxy resin/hardener mix.

404 High-Density: This is an epoxy thickening additive. It’s great for when you need a bit more strength.

405 Filleting Blend: This is a strong, wood-toned epoxy filler. It’s ideal for creating smooth fillets.

406 Colloidal Silica: This is used to control the viscosity of the epoxy. It’s a good all-rounder.

407 Low-Density: This is a blended micro balloon-based fairing filler. It’s perfect for when you need something that’s easy to sand.

409 Microsphere Blend: This is a pure white, hollow glass bubble-based, low-density filler. It’s ideal for when you need a light, easy-to-sand filler. (Only available in the EU)

410 Microlight: This is the ideal low-density filler. It creates a light, easy-to-sand filler when blended with epoxy.

How do you choose the right filler?

Picking the right filler, now that’s a task! It really depends on what you’re working on. If you’re bonding, you’ll want a filler that gives your epoxy some extra muscle. On the other hand, if you’re fairing, you’ll want a filler that sands down easily. It’s all about matching the filler to your project’s needs. You can view our filler’s selection guide for more help.

How do you mix epoxy and filler?

Mixing epoxy and filler isn’t as hard as you might think. First, you mix your epoxy resin and hardener. Then, you add your filler bit by bit, mixing as you go. Keep adding until you get the consistency you’re after.

How do you achieve the right consistency?

Getting the right consistency can be a bit of a head-scratcher. It all depends on what you’re doing. Bonding, fairing, gap filling, they all need different consistencies. But don’t worry, you’ll get the hang of it.

Think of it like this…

Syrup: Un-thickened epoxy, great for coating and bonding fabrics.

Ketchup: Slightly thickened epoxy, ideal for laminating and bonding flat panels.

Peanut Butter: Thicker epoxy mix, perfect for bonding and filleting.