Gaps and seams after gluing a Warhammer model: what causes them and how to fill them
Small seams are normal, especially on push-fit kits and vehicles. A wide gap usually means a leftover sprue stub or a mould line on the join face. Fill what remains with modelling putty or melted-sprue goo and sand it flat.
Plastic glue (£4.15) is the base for sprue goo.
Why the gap is there
A gap usually has one of four causes:
- A stub or mould line on the join. A small lump is enough to stop two parts closing. Clean both faces before gluing.
- Superglue under plastic glue. The two glues do not mix on one join. See plastic glue or superglue.
- The wrong order. In one Reddit thread on the Repulsor Executioner vehicle kit, builders say the gaps shrink if the mount for the grav plate goes in after the main chassis is mostly built. Dry fit before you commit.
- The kit design. Push-fit models in particular show seams along armour edges.
Clean both faces properly and many gaps never happen. See cutting parts off the sprue and removing mould lines.
Dry fit before glue
Games Workshop's building guide for resin kits makes a point that applies to plastic too. Test the parts together before gluing, to see whether any join is uneven or leaves a gap. An uneven join can be flattened with a file or fine sandpaper first. If a gap remains, glue the parts so they are straight and fill the gap afterwards, rather than forcing them.
What to fill the gap with
| Filler | Good for | How |
|---|---|---|
| Melted-sprue goo | Small and medium seams | Fill a pot of plastic glue with sprue offcuts until thick and goopy. Brush it into the gap and sand it flat when set. |
| Modelling putty or filler | Large gaps | Games Workshop's guide uses putty, applied with a sculpting tool, left to set and sanded flat. |
| Epoxy putty | Large gaps and uneven edges | Press it in, smooth it with a damp tool, sand when cured. |
We do not list putty. For goo, you only need glue (£4.15, in stock), a spare sprue and a file.
Filling a seam
- Let the glue cure fully before you touch the gap.
- Press goo or putty into the gap, slightly proud of the surface.
- Smooth it with a damp tool, or leave goo to harden.
- Sand or scrape it flat with the surrounding surface and rinse off the dust.
- Prime the area to check. Primer shows any gap, stub or mould line you missed. Fill and sand again, then prime the patch.
Fix gaps before you paint, because filler is much harder to hide on a painted model.
Common questions
Is a gap on a push-fit model normal?
One r/Warhammer40k thread on the new push-fit models reports visible seams, particularly along armour edges, so a small gap is not a mistake on your part. See which boxes are push-fit for the list.
Can I fix a gap with paint?
Only a hairline. Paint thin enough to hide a gap will not fill one, and a thick coat blurs the detail around it. Fill anything you can fit a fingernail into.
Can I take a model apart to fix a gap?
Plastic-glued joints can often be pried or snapped apart, then cleaned and re-glued. Scrape the old plastic off both faces first. Details are in plastic glue or superglue.
Dry fitting and filling: Games Workshop, A Guide to Building Resin Model Kits (2024), page 4. Causes and sprue goo: hobbyist replies in r/Warhammer40k and r/minipainting threads, 2026. Prices and stock: this shop, read live.