When a tail snaps off

A clean break on a PLA figurine is one of the easier repairs there is, because the two surfaces fit together exactly. The mistake people make is reaching for glue before cleaning the joint.

The repair, in order

• Dry-fit the two pieces and note how they line up before any glue is involved.
• Wipe both broken faces with a damp cloth and let them dry. Dust and finger oil are what make a glue joint fail.
• Use a gel cyanoacrylate, not a thin liquid one. Gel stays where you put it instead of wicking into the layer lines.
• Hold for sixty seconds, then leave the piece alone for an hour. The joint reaches full strength overnight.

When not to repair

If the break is ragged, or if a piece has cracked along a layer line rather than snapping cleanly across one, gluing it will leave a visible scar and a weak spot. Tell us instead. In most cases we would rather reprint it than have a repaired piece on your shelf.

A good glue joint is invisible. A bad one is the only thing you will see.

One caution: cyanoacrylate bonds skin instantly. Keep a bottle of acetone-free nail polish remover nearby, and work over a paper towel rather than over carpet.