Etching titanium with Titan-Etch
Warm or Cold etching?
There are two methods: Warm etching is the recommended method and is described below. It will produce the most reliable and consistent results. Cold etching does not require heating equipment, but results can be less consistent. Read the instructions for cold etching
if you want to try this method.
Supplies & Equipment
Do NOT use any other materials (e.g. glass and metals) than plastic or titanium for handling and storing Titan-etch. If you do, your etching bath will become contamined and lose it's effectiveness.
- Plastic containers/canisters/bowls. (Standard PE or PP type plastics are recommended)
- Plastic or titanium tool(s) for stirring the etchant and handling the titanium parts. For smaller parts a plastic spoon will suffice.
- Distilled water (commonly available at pharmacies, hardware and automotive stores).
- Demineralized or Deionised water (commonly available at pharmacies, hardware and automotive stores).
- A hot plate, metal pan and thermometer (not required for cold etching).
Preparing the Titan-Etch solution
Titan-Etch must be dissolved in distilled water to produce the etchant (etching solution). It is important to use the entire bottle of Titan-Etch when mixing it with the distilled water, since the solid ingredients do not mix homogeneously.
Note: the following instructions are based on the use of 250 g Titan-Etch, which produces 1.85 liters of Etchant. For the 500 g bottles of Titan-Etch simply double the amounts of water and Titan-Etch used below.
- Mix: Pour 250 g Titan-Etch in a plastic storage canister and add 1.85 L of distilled water. Stir the mixture firmly and let it sit overnight to make sure all crystals are dissolved. Shake the canister and give it a good stir before you extract some of the etchant for the etching process.
Storage The etchant can be conveniently stored in a plastic storage canister with lid (as shown in the image). The etchant can be stored for at least 1 year. When you are ready to start the etching procedure, shake/stir the canister and pour out only as much as you need for the task at hand. Do not pour used etchant back in the storage canister, but store it in a separate container (you can re-use this etchant several times).
- Prepare a container with demineralized water, which will be used for rinsing the titanium parts beforehand.
- Prepare a container with distilled water, which will be used after the etching procedure.
- Clean the tools which are used to handle the titanium parts. Use tools that minimize contamination of your etching bath (for example a plastic spoon or titanium wire)
- Make sure you clean the titanium parts thoroughly using degreaser/soap. Don't touch the titanium parts with your fingers after cleaning. Subsequently rinse the parts in demineralized water.
The Etching setup
To heat the etchant you could use a hotplate with a pan of water in which the plastic container with the etchant is suspended (Bain-marie). An example of a simple etching setup is shown in the figure to the right. A thermometer should be used keep a constant temperature.
The reaction time (time you parts are submerged in the etchant) ranges from 15 seconds to more than 5 minutes.
The most important factors that determine reaction time are solubility and temperature.
Solubility: The etchant needs time, heat and stirring to completely dissolve. The first time you are using the etchant it's highly recommended to heat up the etchant (to about 60-70 °C) and stir it for at least 15 minutes. Repeating this process will increase the effectiveness of the etchant. Once the etchant is thoroughly dissolved reaction times should be improved considerably.
The etching process is strongly temperature dependent. I recommend a temperature of around 60 °C. Higher temperatures will speed up the process, while lower temperatures will slow down the etching process considerably
- Other factors: Other factors that could affect reaction time are: finish of your part, thickness of the oxide layer, titanium alloy type(grade), stirring during the etching process and your general setup.
It's advised to perform initial test cycles and see which reaction times and etching conditions work best for your parts.
The Etching process
Submerge the titanium parts in the etchant. Stirring the etchant gives a faster and more uniform result. Try to find your optimal reaction time (i.e. submersion time). If you're not able to anodise your titanium part to all the colors of the spectrum, your reaction time is to short. The optimal reactiontime produces good coloring during anodising while retaining the desired finish of your part. If you found a reaction time that is adequate, you can additionally test the effects of slowly increasing/decreasing reaction time. A slightly deficient reaction time can result in spots appearing on the titanium, while an overextended reaction time can result in a matte or dull finish.
Grade5 titanium will get a slightly darker tint during the etching process. This could be a good indication that your reaction time is adequate.
When the etching process is finished, quickly rinse the titanium parts with distilled water. The parts can be kept in distilled water until you are ready to start anodising. The best results are obtained when anodizing the parts directly after the etching procedure.
Feel free to request
further information on the etching or anodising process.