Lead Leaching Test
This test is to see if a glaze is leaching significant amounts of lead.
The test is not sufficiently accurate to confirm whether or not a piece complies with the legal lead leaching tests, but it will show if a piece is leaching a significant amount of lead, well over the legal limit.
So the way to use it is first to use this test. If it shows no lead leaching, or the leaching test lies in the bottom colour band, then another piece should be sent off to a laboratory for more accurate tests. But if this test shows the leaching is more severe than the lowermost band, then it is not worth sending off to a lab for testing, as it is guaranteed to fail.
Equipment Needed
- Pot(s) or test tiles to be tested.
- Vinegar or a 4% (by volume) solution of acetic acid
- A cotton bud (aka Q-Tip or cotton swap)
- Abotex lead test kit
If testing tiles, a plastic container to hold the acid and test tiles
PPE
None needed.
Procedure
- If testing the glaze inside a bowl, pour the vinegar or acid into the bowl and cover
- If testing tiles, pour the acid or vinegar into the plastic bowl, and add the tiles glaze side up. Ensure that the tiles are fully covered. Cover
- Leave for 24 hours at room temperature
- Pour some of the vinegar or acid from the test into the test kit test tube, so it is about ¼ full
- Dip the cotton bud into the bottle of reagant, and then put it into the test tube. Leave for 1 - 1½ minutes, shaking or stirring periodically
- Hold the test tube liquid or cotton bud against the coloured scale on the lead test kit instructions (whichever is the darker coloured) to read off the lead content.