Updated: Sep 12
After unmoulding a resin piece, there is often a lip edge that artists will want to remove. As always, there are a variety of ways people use to remove the lip edge on resin pieces. Here’s a few examples That you might find helpful.
Some artists use a utility/exacto knife to slice the epoxy lipped edge off. Getting straight clean slices doesn't always happen though, so thankfully there’s other options that may suit you better.
One option is using a deburring tool.
Then after using a deburring tool or a utility/exacto knife, you might need to use a fine sanding block for an even smoother edge. Then use your finger to wipe polish along the edge and use a dremel with the polishing tip to smooth it over. You do not need to polish long, just enough to get the polish saturated. You won't get a mirror finish on the edge this way, so maybe only use this method on the edges that are thin. If you have a thicker edge that's visible after cutting/deburring/sanding, you may need to polish & then buff longer.
There’s a helpful blog about sanding & polishes if you need suggestions in that area. Here's the link to the: Sanding, Polishing, Buffing blog
Or instead of polishing & sanding, after slicing/deburring edges, many people will do a topcoat at this point, since they prefer a slightly rounded finished edge.
Another option some floral artists use on block moulds, is to use a hand wood planer to take off the sharp edge. Then very carefully & lightly sand.
Then I’ve heard they will rub resin into that edge with (gloved) finger. The edge will be smooth and shiny. But this can be tricky & risky to do if you’re not entirely accurate with resin placement on that section only. So use a practise piece first to see if this method might work for you. I’ve tried this once & it did not go well, haha, my hands can be a bit shaky.
Example of deburring tools
Example of deburring tool replacement blades
The swivel on a deburring tool can be awkward to get used to at first. But you can rest your index finger at base of blade (rounded section), to help guide it a bit. I find the swivel more helpful with accuracy. It's also more flexible for different items that have curves (ie geode coaster moulds).
Example of another cutting tool you can try (I have not tried it), but this one does not swivel. Do a web search for:
Hyde Tools 45730 Plastic Cutting Tool
Example of a hand planer (websearch woodworking edge wood planer):
Another way to try to minimize the epoxy lipped edges, is pouring your final layer directly into the middle, so it settles out slowly to the edges, and ends exactly level at top edge, without going over the top edge. But be prepared, resin typically does shrink a tiny bit during cure, so the lipped edge may be unavoidable in moulds.
You can also try a topcoat while piece is still in the mould (usually they’re naturally self levelling at about 1/8” layer out of a mould). For A topcoat layer, pour most of the mix directly in the middle of the piece, & gently glide resin just up to the edges. You can use a silicone brush, silicone spatula, plastic scraper or popsicle stick. Then pour the last bit from cup in the middle again (As if to dome/round). This may help give a bit lower edge Against mould. You’ll need to watch you don’t use too much resin so when it self levels after torching it just barely touches mould. Also remember, if you don’t use enough resin, and add too sparingly, resin then won’t be able to self level correctly and you could instead end up with a bumpy uneven surface.
My own preference is never to use torch in expensive moulds, (risks are too high of ruining it - many beautiful moulds died a quick death that way), so I would just demould piece first. Then topcoat similar to above directions. You can spray a light fine misting of 99% isopropyl alcohol to any surface bubbles that rise up after about 5 to 10 minutes.
When top-coating your piece out of the mould, you can easily torch all bubbles on that layer out. You will need to protect sides from potential drips. So you can either tape up the sides fully (with good quality painters tape), or brush Liquid Latex (be aware many have allergies to latex), or Elmers Glue All on the sides. Let the glue dry well first. Once topcoat is dry, you can remove whatever you used to protect sides, & the drips will come off with it.
Nice clean, smooth edges is a good sign of quality craftsmanship. It's worth the extra time to do, just be sure you are charging enough for your time and materials.
ArtWorks Resin Canada