Markers come in all types of materials, but the most common are painted cast aluminum. Foundries produce cast aluminum plaques. If you’re unsure of foundries in your area, you can contact any local monument works (for cemetery markers) and ask if they might be able to provide the name of a foundry nearby.
Because your marker may be affixed to a post, ensure that the hole dug to support the post is at least four feet deep (1.2 metres) so that the marker will not shift by frost.
Install the marker so that it is neither too high nor too low for readers. Consider that young children and people in wheelchairs will need to be able to read your marker. The middle of the main body of text should be about 57 inches (145 centimetres) from ground level.
If you have a website, you may wish to mention the marker and its exact location. This information will be valuable for people doing local research of their own.