Epoxy resin cures with a shiny or glossy finish, especially on surfaces that are exposed to air during curing, but there are a few ways to get a matte or satin finish on resin.
Use a resin mold that produces a matte or satin finish. When molds are made, the cavities will take on the surface of whatever was used to make the mold. If the mold was made from something with a frosty, rough or coarse surface, that will impart onto the mold. All castings made from that mold will have a matte or satin finish.
How do you know if your mold is going to leave a frosted finish on your resin charms and projects?
Look at the surface of the mold. If it looks dull or frosted, then that same finish will transfer to your resin. This video explains more:
Sand the resin once cured. Resin cures hard enough that it can be, at a minimum, sanded by hand with wet/dry sandpaper. Some resins, such as some casting epoxy resins, and many polyesters and polyurethanes do well with sanding by power tools. When in doubt though, sanding by hand is always the best option. While it takes longer, you are less likely to take off too much or take it off unevenly.
Here’s how you sand resin to get a matte or satin finish:
1. Start with a coarse grit wet/dry sandpaper. When I’m sanding resin, I begin with 150 grit sandpaper if the surface is uneven (like pits, bubbles or fish eyes). If the surface is already even, I start with 400 grit sandpaper. If I’m sanding a small charm, I will sand the charm against the sandpaper. I.e. the sandpaper stays still, and I move the charm back and forth against it. If I’m sanding something large like a painting, I wrap the sandpaper around a sanding block and go over the surface. I.e. the resin stays still and this time I move the sandpaper. Your surface will look very ‘scratchy’ at this point, especially if you started with very coarse sandpaper.
Note: Wet the sandpaper. This serves two purposes: the water will wet the dust, so you don’t inhale it and it cools the heat from friction, so your piece doesn’t melt.
Safety tip: Wear a particle mask when sanding resin. You do not want to inhale resin dust.
2. Once the surface is completely sanded and even, choose the next finer grit of sandpaper and repeat. When I’m sanding resin, I will use wet/dry sandpaper as follows: 150, 400, 600, 800 and 1000. Once you have ended with 1000 grit paper, you will notice your resin is slightly frosty, but you can see the details of your project.
Important: you must make sure your resin is evenly sanded with a grit before moving on to the next grit. If there are marks, divots or other blemishes you see that you can’t get rid of with the grit you are currently using, you need to go back a step and sand again with a coarser grit paper before moving on.
3. Continue sanding with finer grit sandpapers until the surface is as matte or frosty as you like.
Pro tip: Once you have finished with at least 1000 grit or higher, you can recoat with another layer of resin and it will go glossy again without seeing the scratches underneath. This comes in handy in case you decide you really don’t want a matte or satin resin finish after all. If you do recoat with another layer of resin after sanding with only coarse papers, your new layer will have a glossy finish, but the sanded resin underneath will look matte.
Here’s how I like to sand resin jewelry and resin paintings:
So why can’t you use power tools to go over the surface of your resin jewelry, crafts or art?
Well, you might be able to. The problem is that if you used an epoxy resin that cures soft, the friction from sanding may cause your piece to ‘crumb’ and not sand off evenly. It can also warp or melt. If you decide to use power tools, keep the resin wet if possible, to reduce the heat and friction. Pay careful attention as resin sands off quickly when using power tools.
How do I use power tools when sanding resin?
I will use them on hard-curing resins when I’m sanding a flat surface like the backs or straight sides of resin charms. For the times I’m sanding a curved or uneven surface, I will sand by hand. I find it’s very tedious to keep power tools from changing the shape of your resin casting.
If you want to try, here are some techniques to help:
When do I sand resin artwork?
When the divot or blemish I’m trying to correct us more than 1/8 inch deep, I will sand resin. Doming resins for artwork self-level to 1/8 inch deep, so you don’t want anything any deeper than that. Otherwise, you will end up with divots in the next layer too.
Note: Please take appropriate safety precautions when sanding resin, which includes wearing a dust mask. Here’s more information on resin safety.
What about using additives to get a matte or satin finish on resin?
While I’m sure there are some out there, I’m a big believer in the mantra, ‘the simplest way is usually best’. While I hate sanding, I don’t want to take a chance using a product that may not produce the exact finish I want. At least with wet/dry sandpaper, I can sand the resin to the exact finish I want.
Need more details on sanding resin? This article will help: How to sand resin
Do you like to have a matte or satin finish on resin projects?
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