Trade Secrets: We asked Hamish: can you colour epoxy?
WEST SYSTEM® epoxy is renowned for its clear finish. However, what if you just want to add a splash of colour to your epoxy? In this month’s ‘Ask Hamish’, he explains how to bring the colours of the rainbow to your next epoxy project.
If you look at the range of WEST SYSTEM pigments available, you’d be forgiven for thinking you can only tint your epoxy four colours: black, white, grey or blue. However, it’s actually possible to make epoxy any colour you like.
Below, I’ll talk you through some specific things to remember when adding different kinds of coloured pigment to your epoxy blend – but first, bear in mind these four general points:
- Check that the pigment is suitable.
It should be marked specifically as being OK to use with epoxy.
- Always use the specified amount of pigment.
Pigments may have an effect on the strength of the epoxy. However, when used correctly (typically 3-5% by volume), this should be minimal.
- Only add the pigments to the secondary and/or final coats of epoxy.
The change in viscosity can affect how the epoxy penetrates and seals surfaces.
- Always do a test run.
Check the opaqueness of colour, how good the cure is and whether you’re happy with the final finish, before you do any actual work on your project.
WEST SYSTEM pigments
This fine powder is purpose-designed to work with WEST SYSTEM epoxy and it blends in completely, giving you an ultra-black finish. Many of our customers add it to epoxy that has been thickened with 404 High-Density Filler, creating a paste that they can use on their teak decks to replicate the look of traditional seams. You can also use the powder to darken other coloured pigments.
These pigments differ from the Graphite Powder in that they’re suspended in an epoxy-based liquid. While they are designed for use with WEST SYSTEM epoxy, you do need to be careful that you only add the specified amount to your epoxy blend, to avoid changing the resin/hardener ratio and affecting the overall cure.
Water-based aniline dyes
These powdered colouring agents are available in a range of colours, including natural wood colours. While they provide a good effect, they won’t blend completely into the epoxy, meaning that – if you look closely – you may be able to see flecks of powder. However, these dyes don’t typically weaken the epoxy as much as some other pigments can.
Acrylic paste pigments
Acrylic pigments mix more evenly into epoxy than powdered pigments but they do tend to weaken the epoxy slightly. However, you may decide that colour is more important to your particular project than strength – and there certainly are plenty of acrylic colours to choose from. Think of an artist’s palette and take your pick!
Don’t forget UV protection
It goes without saying that none of the colourants we’ve talked about here offer any UV protection. So if your project is for outdoor use, or is going to spend some time in direct sunlight, then make sure you add a protective varnish after you’ve applied your coloured epoxy.
Thanks very much to Hamish Cook for his expert advice.
Visit the West System International website for more information on the full range of additives, including pigments.