> For the complete documentation index, see [llms.txt](https://delta-robotics.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://delta-robotics.gitbook.io/docs/learn/how-to-train-nitinol/basic.md).

# Basic

Shape-set Nitinol wire at home with common tools like a torch or stovetop, plus the safety steps and cooling technique to do it right the first time

Shape-setting Nitinol at home takes only common tools: a torch or a stovetop, something to hold the wire, and the right safety gear. You'll bend the wire into a shape, heat-treat it, then cool it so the wire remembers that shape. This guide keeps the methods simple and the safety front and center.

{% hint style="danger" %}
**Work safely: this process involves high heat.** At around 550 °C, the wire and tools are extremely hot.

* **Protective gear:** Wear heat-resistant gloves, safety glasses or goggles, and protective clothing.
* **Ventilation:** Work with good airflow. Heated metal can emit fumes.
* **Fire safety:** Keep flammable materials away and a fire extinguisher within reach.
* **Tool handling:** Use pliers or tongs, and never touch the hot wire directly.
* **Quenching:** Quench in water at arm's length, using a metal container, to avoid steam burns.
  {% endhint %}

<details>

<summary>Disclaimer and liability</summary>

Working with Nitinol involves high-temperature processes and equipment that carry inherent risks. Delta Robotics provides these guidelines for educational and informational purposes only. It is your responsibility to exercise caution, follow all provided safety instructions, and take appropriate safety measures.

Delta Robotics shall **NOT** be held responsible for any injury, damage, or loss incurred through improper or unsafe handling of materials, equipment, or processes described in our guides. Prioritize safety at all times and perform these procedures at your own risk.

</details>

## What is shape-setting?

Shape-setting (or training) gives Nitinol a permanent shape that it returns to when heated. Nitinol is a **shape memory alloy**: train it to a shape at high temperature, bend it at lower temperatures, and it springs back to the trained shape when you reheat it. Heating above a certain transition temperature makes Nitinol's crystal phase revert to the trained form.

## Tools and materials

Common hobbyist tools are sufficient for shape-setting Nitinol. Here is what you'll need:

* **Nitinol wire:** Clean and free of any insulation, available from Nitinol suppliers.
* **Form or fixture:** Metal jig, rod, tube, or pliers. The fixture must withstand high heat (steel or ceramic; aluminum will not work).
* **Heat source:**
  * **Furnace (recommended):** Offers accurate, consistent heating. Ideal for uniform shape-setting and preventing overheating.
  * **Propane or butane torch:** Good for focused heating, but requires careful control to avoid overheating.
  * **Gas stovetop burner:** Suitable for small pieces but demands constant movement to prevent hotspots.
  * **High-wattage soldering iron:** Slow and limited to smaller sections; may not consistently reach desired temperatures.
* **Thermometer (optional):** An infrared thermometer or thermocouple helps verify temperature (around 550 °C corresponds to a very dull red glow).
* **Water container:** A bucket or bowl for quenching, big enough to fully submerge your wire and fixture.
* **Pliers and wire cutters:** To handle fixtures and trim wire.

{% hint style="warning" %}
Kitchen ovens do **not** reach the required temperatures (around 550 °C).
{% endhint %}

## Shape-set the wire

Follow these steps to form and heat-treat your wire.

{% stepper %}
{% step %}

### Design and pre-shape the wire

Choose and form the shape at room temperature (coils, zigzags, and so on). Over-bend slightly to compensate for spring-back, since Nitinol relaxes a little during heat treatment.

Use fixtures or jigs (steel rods or clamps) to hold the wire in its desired form during heating.
{% endstep %}

{% step %}

### Secure the wire in the fixture

Fasten the wire so it holds its shape during heating, using binding wire, bolts, or clamps (steel or ceramic only). Firm fixation stops the shape from distorting as Nitinol softens at high temperature.
{% endstep %}

{% step %}

### Heat the wire (around 550 °C)

Apply heat evenly:

* Aim for around 550 °C (very dull red glow).
* Heat for at least 20 minutes.

Heating at this temperature rearranges Nitinol's internal crystal structure and locks the shape into memory. Manufacturers recommend 500 to 550 °C for reliable shape-setting \[1]\[2].

By heat source:

* **Furnace:** Set to around 550 °C, insert fixture and wire, and hold steadily for at least 20 minutes. Provides uniform and controlled heating, minimizing risks of overheating or uneven memory effects.
* **Torch:** Move the flame steadily across the wire to distribute heat evenly.
* **Stovetop:** Place wire above a blue flame and continuously move it to prevent hot spots.
* **Soldering iron:** Apply directly in segments, recognizing it may not fully reach 550 °C consistently.
  {% endstep %}

{% step %}

### Quench (rapid cooling)

Immediately quench in water after heating to lock the shape. A fast quench freezes the internal structure, which preserves the trained shape and prevents unwanted structural changes \[3]\[4].

Hot steam may form, so handle it carefully.
{% endstep %}

{% step %}

### Remove the wire from the fixture

Once cooled, remove the wire from the fixture. It should hold its shape on its own, which confirms the shape-setting worked.
{% endstep %}

{% step %}

### Test shape memory

Deform it slightly at room temperature, then heat it briefly (hot water, heat gun, or flame) and watch it return to its trained shape. Minor imperfections on the first try are normal and usually improve after a few cycles.
{% endstep %}
{% endstepper %}

## Recap and key points

* **Temperature and time:** Around 550 °C for at least 20 minutes \[1].
* **Shape fixation:** Secure wire firmly in the desired shape before heating.
* **Cooling:** Quench immediately to preserve microstructure and shape \[3]\[4].
* **Safety first:** Adhere strictly to safety recommendations.
* **Simplicity of tools:** Accessible methods (furnace, torch, stovetop) suffice for hobbyists.
* **Understanding results:** Properties improve with repeated training cycles; initial slight imperfections are normal.

Your wire is now trained and shows the shape memory effect. For finer control, continue to the [Advanced guide](/docs/learn/how-to-train-nitinol/advanced.md).

## Related pages

* [Advanced](/docs/learn/how-to-train-nitinol/advanced.md): Precision shape-setting for engineers and researchers.
* [Electric](/docs/learn/how-to-train-nitinol/electric.md): Shape-setting with the ThermoFlex Node.
* [What is Nitinol?](/docs/learn/nitinol-faq.md): The materials science behind the shape memory effect.

## References

\[1] [Kellogg's Research Labs: Nitinol Shape Setting Guidelines](https://kelloggsresearchlabs.com/)

\[2] [Medical Device Components: Nitinol Heat Treatment](https://medicaldevicecomponents.com/)

\[3] [PMC: Nitinol Shape Memory Alloy Processing](https://pmc.ncbi.nlm.nih.gov/)

\[4] [ScienceDirect: Nitinol Heat Treatment and Cooling Effects](https://www.sciencedirect.com/topics/engineering/nitinol)