Pick the Material
The first dropdown narrows the chemistry to ones that actually bond your filament. Choosing the wrong material here is the #1 reason adhesion fails:
- PLA — bonds with almost everything. CA, epoxy, PU, hot glue.
- PETG — surface energy is lower. CA + activator works; solvent welding does not.
- ABS / ASA — solvent welds with acetone. CA bonds well too.
- TPU — flexible CA only, or specialty flexible epoxies. Standard CA cracks under flex.
- Nylon — notoriously hard to glue. Two-part PU or specialty nylon adhesives.
- Resin — CA bonds beautifully. Two-part epoxy bonds even better.
If you mix materials in one print, choose the more difficult one (TPU, Nylon, PP-style materials) — the recommendation will list adhesives that bond both.
Describe the Joint
The Joint Type dropdown changes the recommendation more than anything else, because joint geometry decides whether you need flexibility, gap-filling, or instant tack:
Alignment (peg + hole)
Thin film of CA on the peg. Bonds in seconds. Add an activator spray if your CA is sluggish.
Flat lap
Large overlapping flat surfaces. Use epoxy for area or solvent weld for chemical fusion (ABS).
Butt joint
Two cut faces meeting end-to-end. Structural epoxy or PU. CA is too brittle for any load.
Gap-fill
The joint is not flush (warp, slight misprint). Gap-filling CA or two-part epoxy with thickener.
Cosmetic
Surface bond only, no structural load. Hot glue or thin CA.
Quantify the Bond
Enter the Total Seam Length in millimetres and the Average Bond Width. The calculator multiplies these to get the bond area, applies the typical coverage rate of the recommended adhesive, and returns a quantity in grams.
- 200 mm seam at 5 mm width ≈ 1 g of CA, or 3 g of two-part epoxy.
- 1 m seam at 8 mm width ≈ 8 g of CA, or 22 g of epoxy.
- Two halves of a 30 cm-tall bust meeting at the chest ≈ 600 mm at 6 mm = 4 g CA / 12 g epoxy.
The numbers help you avoid both running out mid-glue and over-buying a bottle that will solidify before you use it.
Use Case Shapes the Answer
The Use Case picker refines the recommendation based on what the print actually has to do:
- Display — speed and invisibility win; CA + activator dominates.
- Cosplay — impact resistance matters; shifts toward flexible CAs and rubberised epoxies.
- Functional — load-bearing; structural epoxy or solvent welding.
- Outdoor — UV and moisture resistant; rules out CA, favours PU and silicone.
Read the Alternatives Field
The recommendation panel always lists 2–3 alternatives. If the top pick is a specialty product you do not have, the next-best option is usually only marginally weaker — pick the one already on your shelf rather than ordering and waiting two days.
Safety Notes
- Activator sprays for CA are flammable and irritant — ventilate.
- Acetone solvent welding needs a fume hood or open garage; vapours displace oxygen in enclosed rooms.
- Two-part epoxies have a working time (pot life) measured in minutes — lay out the parts before you mix.
- PU adhesives need a damp surface to cure properly — lightly mist with water before clamping.
Pairs Well With…
- Slicer Pro — the segments come out of Slicer Pro with measured seam lengths; feed those straight into this calculator.
- DowelPro — for dowel-pin assemblies, use the alignment recommendation here for the dowel and a structural pick for the seam.
- Mega Estimator — budget filament and adhesive in one place when planning a multi-part build.