Resin printing creates much smoother prints and can capture much higher quality detail than FDM printing. As a result, resin prints can look quite pretty right off the printer/curing unit. You can use resin prints as-is, or you can follow this guide to get them looking smooth as can be!
First things first.
Resin prints can sometimes be more fragile than FDM printed pieces. If you ordered a physical kit from us, we recommend double-checking all your resin printed pieces before starting to work on them. While we pack all of our resin kits with the utmost care, a lot of our orders have long travels all over the world and couriers aren't getting any gentler. If you notice any resin casualties in your accessory/prop kit, please contact us here.
Part of the process of resin printing is to wash the prints in isopropyl alcohol after printing and before curing. As you can imagine, we have a lot of orders we cycle through, and sometimes the isopropyl can hold excess resin. Some pieces can become sticky after curing and as a result of being packaged for an extended length of time - particularly prints that have been hollowed out to reduce weight, as these can hold the wash solution inside in deep crevices. Hot weather/climate can also cause issues here. If you notice any slightly sticky resin prints, please wear gloves while handling the pieces! We recommend wiping them over with rubbing alcohol and leaving them in the sun (or putting them under UV light if you have one). We are working hard to ensure everyone gets high quality kits with no issues, but this can sometimes be out of our control due to transit and external handling of orders. Thank you for understanding!
A Note on Safety
When finishing resin prints, please ensure you are working in a well-ventilated area, wear gloves (preferably nitrile not latex) as uncured resin can cause skin irritation if handled incorrectly, have a mask/respirator and safety glasses. Resin sanding dust is very fine and not something you want to be breathing in. Safety comes first, especially when making cosplays!
Our Resin Printing Applications
We tend to use resin printing for smaller parts of accessory kits (and FDM for large pieces), and also some delicate or high-detail parts of prop kits. We also favour resin printing for gems found in both props and accessory kits. The process we use for finishing gem-like kit pieces is a little more involved than our process for finishing standard accessory kit pieces or delicate pieces of props, and needs a couple more supplies.
A Brief Supplies List
- 2-Part Epoxy (for prop kit pieces/adding attachments to accessories)
- Nitrile gloves
- Gap Filler**
- 240 grit sand paper
- 400 grit wet/dry sand paper
- 600 grit wet/dry sand paper
- 1200 grit wet/dry sandpaper*
- Sanding pads/cushion set (from 1500 - 3200 grit)*
- Face mask/respirator
- Tub of water
- Primer/base coat paint
- Foil backing (look up foil transfer sheets!)*
- Acrylic lacquer/gloss top coat*
*items only needed for gem-like resin pieces
**item only needed if the resin piece is hollowed out (will have small 3-5mm holes in the back) or is a larger prop piece being attached to a full prop kit.
For more insight into specific supplies, we have a full, in-depth list of all the finishing supplies we use in-house with bonus context of why we use these specific brands over others - check out our recommended supplies here!
Getting Started
Resin printing often uses additional material for support which can leave dots/puckering on printed surfaces. Larger resin pieces also get hollowed out, which will leave small holes in the underside of pieces. The finishing process below will help smooth these out!
Most of the time, some resin pieces can get away without being sanded at all! This is part of the reason we resin print our small accessory kit pieces. If you're happy with the finish of the pieces as they are (and they don't have any puckering from supports/holes from hollowing out), you can just hit them with a plastic primer before starting on your paint job!
Gap Filling
If your resin printed kit has some larger pieces, we may have hollowed these out to reduce both weight and material usage. You can identify hollowed-out pieces by small 3-5mm diameter holes in the underside of the print.
For pieces with these holes, you'll want to plug them up with gap filler of your choice. You can be quite generous here - the holes will generally be on an unseen side of your accessory piece, and you'll want to sand the excess back anyway. Start with plugging these holes, and make sure the gap filler is completely dry before you move onto sanding!
Sanding
Grab your mask, gloves, sanding supplies and water tub, it's time for sanding! Make sure you're wearing messy clothes, are working in a well-ventilated (and non-carpet) area, with animals and/or children shut away.
Basic sanding rules: start at your low grits and make your way higher! The more grits you pass through, the smoother finish you'll end up with. You can absolutely skip straight from 80 to 400 if you're impatient, but going through all the grits in between will give you much nicer results. But how in-depth you go here is entirely up to you!
Check through all the pieces of your accessory kit, and separate any pieces that have the stippling from supports (as pictured above in "Getting Started"). On these pieces only, start with your 240 grit. Also use 240 grit on any pieces you gap-filled in the previous step. Sometimes you may run into stubborn areas - if you're having trouble at 240 grit, you can try out 120 grit sandpaper instead but we don't recommend using 80 grit on resin. We find 80 grit can leave decent scratches on resin pieces, so we start at a finer grit even though it can be a bit more temperamental as it leaves a nicer finish. Finer grits can also leave some micro scratches if you are rough - try to sand in circular motions rather than harsh lines.
After your 240 grit, it's time to move onto your main sanding job. Fill a large tub with water and a dash of dish soap (this will help your sand paper clog up less). If your printed piece is small enough, you can submerge it in the water while sanding. If not, dip your sand paper in the water before sanding. You may also find it useful to have a cloth on hand to wipe your piecedown every now and then if it can't be submerged.
Now start wet-sanding at 400 grit. As with the 240, try to sand in circluar motions. Once you've sanded all sides and crevices at 400 grit, give your piece a rinse in the water tub and move up to 600 grit. Repeat this at 600 and 800 grit.
You can stop here and hit your pieces with primer (once they've dried) if they're just regular accessory/prop kit pieces. You're all good to paint! For more insight into what paints we use in-house, see our recommended supplies list!
Gem-Like Resin Pieces
If you have gem-like resin pieces in your kit, they need a little extra finishing! You can stop sanding at 800 grit, or if you want extra shine, we recommend trying out 1200 grit sandpaper and sanding pads ranging from 1500 grit to around 3600 grit. These generally come with polishing compound and can get your gems really smooth and gorgeous! That is, of course, quite a bit of work so it's entirely up to you how far you go with sanding and polishing.
Once you're happy with your finish, whether you've sanded to 800 grit or 3600, we recommend hitting your gems with a coat of acrylic lacquer for a nice shine! You can layer up a few times if you're not happy with the initial finish. You can also polish the lacquer further if you think it needs it!
Most of our gem-like pieces will then need to be glued into place in their respective prop/accessory kit pieces. For this, we recommend Gorilla Glue Clear. If you're worried about your glue being visible now your gem is nice and shiny and clear, we recommend adding a foil backing! We found best results using spray contact adhesive on both the back of the gem and the foil - but instead of waiting for the adhesive to dry/go tacky as the instructions recommend, press the gem onto the foil while the adhesive is still wet. This stops the gem from clouding!
For more insight into what supplies we use in-house, see our recommended supplies list!
