How to replace a broken or discontinued plastic part

What should you photograph?

Photograph the part from enough angles that someone who has never seen it could picture it in 3D. That means multiple sides, both faces of the break if it's snapped in two, and a shot showing how it mounts or connects to whatever it attaches to — screws, clips, a press fit, a slot. If the part has any moulded text, logos or a part number, photograph that closely too: these often identify the original component or an equivalent that's still available to buy, which can save you the cost of reprinting altogether. If the part is still installed somewhere, a photo of it in place is genuinely useful — it shows orientation and clearance that a photo of the part alone doesn't.

How do you measure it?

Vernier calipers are ideal because they give you precise readings on the dimensions that matter most: overall length, width and thickness, hole diameters, and centre-to-centre distances between mounting holes. If you don't have calipers, a steel rule against the part works for most measurements — lay a coin or ruler in the photo next to the part so scale is obvious even without a written number. Focus on the dimensions that control fit: how far apart the mounting holes sit, how thick the material is, and any step or lip that another part locates against. A rough estimate of every other dimension is fine, because we confirm fit with a test print before committing to the final part.

Which parts suit FDM printing?

Brackets, clips, knobs, housings, spacers, mounts, and gears under light-to-moderate load are a good fit — these are the everyday parts that break and stop being sold. Parts exposed to sustained heat, in contact with food, carrying structural or safety-critical load, or needing the strength of metal are assessed at the quote and steered to the right process; watertight parts are designed around a bought seal. Very fine detail — sharp text, thin snap-fit tabs under repeated flexing, or precision beyond what a printed part reliably holds, such as close-fitting mechanical tolerances, fine threads, or precision bearing surfaces — is also a stretch for this process, and those are better machined. Every quote sets out which route suits your part before anything is made. Where the part is off a machine and no supplier exists, obsolete machine parts covers the process, and reverse engineering covers working from the original alone.

Which material should you choose, and why?

PETG suits most tough functional parts — brackets, housings, anything handled roughly or left outdoors — because it holds up better to knocks and UV than PLA. PLA is fine for light-duty parts that just need to hold shape and aren't under real load, and it's the easiest material to print with a crisp finish. Flexible TPU is for parts that need to bend or seal, like gaskets, grips, or cable strain reliefs. If a part needs more stiffness or wear resistance than PETG offers, machining or a metal part is the right call, and you should expect a supplier to say so at the quote — though most household and light workshop parts never reach that point.

What should you realistically expect?

A working replacement, not a cosmetic twin of the original. FDM printing leaves visible layer lines on the surface, and while we can print in a colour close to the original, colour is matched as closely as available filament allows. What you do get is a part built to measure, tested for fit before it's finished, and made in a material chosen for how it'll actually be used — which for a broken bracket or a discontinued knob is usually exactly what's needed. For the full process on getting one made, see our replacement parts page, and if you want a sense of what it costs before you enquire, our guide on custom part pricing covers what drives the number.

Frequently asked questions

Do I need to send the broken part itself?

Not always. If it's a simple shape, clear photos with measurements or a scale reference are often enough. For anything that has to mate precisely against another component, sending the broken piece makes the model more accurate and the process faster.

What if I don't have calipers?

A steel rule works fine for most parts. Lay it flat against the part in the photo, or place a coin or ruler next to it for scale, and note the key dimensions — overall size, hole spacing, and thickness — as best you can.

Will the reprinted part look exactly like the original?

No — expect a functional match, not a factory-finish cosmetic one. FDM printing leaves visible layer lines and colour matching is limited to the filament colours available, so the part will work like the original but won't be indistinguishable from it.

What if the moulded part number is still visible?

Photograph it and send it to us. A moulded part number can sometimes identify the original manufacturer or an equivalent part that's still available to buy, which can be cheaper and faster than reprinting.