How to Fix a Broken Resin Miniature: Gluing, Pinning, and Hiding the Repair
Resin snaps clean instead of bending. Here is how I glue, pin, fill, and repaint broken miniatures so the repair holds up to actual play and disappears under paint.
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The first miniature I broke off the Saturn was a wizard with a staff about as thick as a matchstick. I picked him up by the staff, which was stupid, and it snapped at the hand with a sound like a dry twig. No bend, no warning, no white stress mark first. Resin does not fail gradually. It holds absolutely fine right up until it does not, and then it comes apart in two clean pieces.
That clean break is the good news. A snapped resin part is usually far easier to repair invisibly than a snapped plastic one, because the two fracture faces still fit each other perfectly. This guide covers the whole repair: triage, gluing, pinning the joints that need it, filling the seam, and blending the repair back into the paint job. If the model is not painted yet and you want the full finishing workflow instead, start with the complete guide to painting 3D printed resin miniatures and come back here the first time something snaps.
Why Resin Breaks the Way It Does
Cured MSLA resin is hard and brittle. That is not a flaw in your printing, it is the trade-off that buys you the detail. The same tightly cross-linked chemistry that holds a 0.2mm sword edge and crisp chainmail leaves the material with almost no ability to flex. A plastic Games Workshop spear bends forty degrees and springs back. The resin equivalent takes the load without moving at all until the cross-section fails, and then it fails completely.
Three things make it worse:
Over-curing. Resin left in a UV chamber for twenty minutes when it needed four gets measurably more brittle. This is the most common self-inflicted cause of fragile prints. If your models seem to snap more than everyone else’s, check your cure times against the curing guide before you blame the resin.
Print orientation. A spear printed vertically has its layer lines running across the shaft like perforations on a paper towel. The same spear printed at an angle, along its length, is dramatically stronger. Orientation is not only a surface-quality decision, it is a structural one.
Standard resin on a model that should not have used it. A display piece that lives on a shelf can be printed in anything. A character that gets picked up thirty times a night deserves a tougher blend.
Knowing which of these caused the break matters, because the repair is only half the job. The other half is making sure the same part does not snap again next month.
Triage: What You Actually Have
Before reaching for glue, work out which of three situations you are in. They need different treatment and one of them is not worth repairing at all.
| Break type | What it looks like | Approach |
|---|---|---|
| Clean break | Two pieces, faces mate with a hairline seam or none | Glue, plus a pin if the cross-section is thin |
| Crushed or crumbled | Faces do not mate, small fragments missing, gap when closed | Glue and pin, then fill and reshape the seam |
| Shattered or lost | Three or more fragments, or a piece you cannot find | Reprint the model, or sculpt a replacement part |
The honest answer on that last row: if the model is unpainted, reprint it. A 28mm figure is a few cents of resin and a few hours of print time you spend asleep. You will never fully un-see a rebuilt shoulder on a model you repaired, and a reprint gives you a clean one. If you need a fresh file or a replacement sculpt, the STL sources roundup covers where to find them.
Repair earns its time on painted models, on large pieces that ate real resin, and on anything from a subscription release you cannot easily reprint.
Find the missing piece first. Search the table, the floor, and the case before you commit to anything. A repair with the original part is nearly invisible. A repair with a sculpted replacement is a different, much longer job.
Tools and Materials
The full kit runs about twenty-five dollars and most of it you will already own if you have removed supports before.
Gel super glue. Thick-formula cyanoacrylate, the gel version rather than the thin. It grips cured resin properly, fills a hairline seam, and stays where you put it instead of running into recessed detail. Loctite Gel Control and Gorilla Super Glue Gel are both fine. Do not reach for plastic cement: it works by melting polystyrene, and cured photopolymer resin does not melt, so it does nothing at all.
CA accelerator. Optional but useful. It cures the joint in seconds instead of a minute of holding. The catch is that it removes any chance of correcting a crooked join, so only spray it once you are sure the alignment is right.
A pin vise and small drill bits. A hand-turned pin vise in the 0.5mm to 1.5mm range. This is the one tool most people skip and then wish they had. Hand-turning is not a limitation here, it is the point: a power drill grabs brittle resin and cracks the part you are trying to save.
Brass rod or paperclips. Brass rod in matched sizes is tidier. A straightened paperclip works and costs nothing. Either way, match the pin to the drill bit so the fit is snug rather than sloppy.
Fine flush cutters. For cutting pins to length and cleaning up the break. The same Xuron Micro-Shears you use for support removal handle brass rod without complaint.
Liquid Green Stuff and two-part putty. Liquid Green Stuff brushes into a hairline seam and cures in an hour. Two-part epoxy putty, either Green Stuff or Milliput, handles anything with real volume to fill. This is the same fill technique covered in the guide to removing support marks, and it works identically here.
A magnifier headset. Genuinely worth it for pinning. Drilling a centered 1mm hole into a 2.5mm wrist is guesswork at arm’s length and straightforward with magnification.
Nitrile gloves. Super glue bonds skin instantly and enthusiastically, and if you are working on a recently printed model there may still be uncured resin in recesses. The resin safety guide covers handling in full.
Gluing a Clean Break
For a wide-contact break with no pin needed, this takes about five minutes.
Clean both faces. Wipe each mating surface with isopropyl alcohol on a cotton bud. You are removing skin oil, dust, and any uncured resin film. On a painted model, scrape the paint off both faces down to bare resin with a knife tip. This step is not optional: glue bonded to a paint film holds only as well as the paint’s grip on the resin underneath, and under stress the whole repair peels away with a flake of paint attached.
Key the surfaces. Scuff both faces lightly with a knife tip or the corner of a needle file. A slightly rough surface gives the adhesive mechanical grip on top of its chemical bond.
Dry-fit once more. Press the pieces together with no glue and confirm the seam closes tight and the part sits at the right angle. This is your last free look.
Glue and hold. A small amount of gel on one face only. Too much glue squeezes out into surrounding detail and cures into a shiny ridge that is harder to remove than the original break was. Press, align, hold for thirty seconds.
Give it a few minutes before handling. Full cure on gel CA is a couple of hours, and the joint is at its weakest during the first ten minutes.
Pinning: The Repair That Actually Holds
Anything narrower than roughly 3mm needs a pin. Wrists, ankles, weapon shafts, spear hafts, thin banner poles, the join where a wing meets a back. Super glue on a thin resin cross-section is a repair that lasts until the next time someone picks the model up by that exact part, which for a mini in regular use doesn’t take long.
A pin turns a butt joint into a joint with a metal spine through it. The glue stops being the thing carrying the load.
Mark your centers. Press a knife tip into the middle of each face to make a dimple. A drill bit set down on a smooth curved resin face will skate; it will not skate out of a dimple.
Drill both halves. Hand-turn the pin vise, keeping the bit aligned with the axis of the part rather than across it. On a spear, that means drilling down the length of the shaft, not sideways into it. Two to three millimeters deep in each half is plenty at this scale. Go slowly and back the bit out occasionally to clear resin dust.
Cut the pin slightly short. Measure both hole depths, add them together, and cut the rod a hair shorter than that total. A pin cut too long holds the pieces apart and leaves a permanent gap at the seam, which is the most common pinning mistake.
Test the fit dry. Seat the pin, close the joint, check the alignment from several angles. Adjust before glue, not after.
Glue it up. Gel super glue in one hole, seat the pin, a thin film on the mating face, close the joint. Hold. If the alignment is right and you want it locked immediately, a light spray of accelerator sets it in seconds.
On very fine parts where even a 0.5mm hole would blow out the side, skip the pin and accept a glue-only repair, but redesign your handling: that model gets carried by its base, permanently.
Filling and Blending the Seam
A pinned joint usually still shows a faint line. On a painted model that line catches the light and reads as damage even after repainting, so it needs filling.
Dab Liquid Green Stuff into the seam with a small detail brush. Do not brush it along the seam, dab it in, letting it sit slightly proud of the surface. Rinse the brush, then wipe the excess flat with the damp brush. The water softens the top layer and feathers it into the surrounding surface. An hour to cure, then blend with a fine sanding stick until you cannot feel the transition with a fingertip.
Larger gaps, and anywhere the fracture crumbled instead of splitting cleanly, need two-part putty. Mix a small amount, press it into the void, and shape it with a dental pick or a sculpting tool moistened with water so the putty does not stick to it. Epoxy putty takes hours to cure but holds its shape under sanding far better than the liquid version.
If the break ran through sculpted detail, like a chainmail sleeve or a fur cloak, re-scribe the texture into the cured filler with a knife tip before priming. Matching texture badly still reads better than a smooth blank patch where detail should be.
Repainting the Repair
Spot-prime with a brush-on primer such as Vallejo Surface Primer or Stynylrez rather than spraying the whole model. You want primer on bare resin and cured filler only, not another coat of texture over your existing paint. Brush-on primers exist for exactly this. If you are picking one for general use, the primer comparison covers how each behaves on resin specifically.
Then rebuild the paint in the same order you originally did: base coat, shade, highlight. Use a fine detail brush and keep the repaired area’s coats thin, since thick paint on a repair reads as a lump under raking light.
Finish by re-varnishing the repaired section so the sheen matches. A matte repair on a satin model is as visible as the crack was. Vallejo Matte Varnish brushed over the area, or a light pass of Testors Dullcote, blends it back in. The varnishing guide covers matching sheen across a model in more detail.
Stopping the Next Break
Repairs are a symptom. If you are gluing something back on every few weeks, fix the cause instead.
Print fragile models in a tougher resin. Blending a flexible resin into your standard bottle, or printing outright in an ABS-like blend, gives thin parts enough give to survive being picked up. Siraya Tech Tenacious is the usual choice for blending in flexibility, and Siraya Tech Blu or Elegoo ABS-Like print tougher straight from the bottle. The full comparison is in the ABS-like resin roundup.
Orient long thin parts along their length. A spear at an angle prints along its strong axis. A spear standing vertically prints as a stack of discs waiting to shear. The same applies to banner poles, tails, and outstretched arms.
Support the fragile parts properly. Under-supported thin extremities flex during peel and arrive already micro-fractured, which is why some models seem to break for no reason at all. The support placement guide covers density and tip size on thin geometry.
Cure to the right point and stop. More UV is not better. Over-cured resin is brittle resin.
Store and carry models properly. Most breaks happen in a bag, not on the table. Foam trays, magnetized bases, and separating the spiky models from everything else prevents more damage than any repair technique fixes. Sealing the paint first helps too, which the varnishing guide covers in full.
What I Do Now
That wizard is still on the shelf. The staff is pinned with a paperclip, filled with Liquid Green Stuff, and repainted, and I genuinely cannot find the seam without knowing exactly where to look. It took about forty minutes.
What changed after that is not my repair technique, it is everything upstream of it. Anything with a thin protruding part now gets printed in a blend with Tenacious in it, gets oriented so the thin part runs along its length, and gets carried in foam rather than loose in a box. I still repair a model every couple of months. It used to be every couple of weeks.
Keep a pin vise, a few drill bits, a length of brass rod, and a bottle of gel CA in the same drawer as your cutters. When something snaps, and it will, the repair is a forty-minute evening job instead of a reprint.