Dichtewaage / Density Scale

All you need is a fine scale and a synthetic thread or very thin wire (I used 0.4 mm2 tinned copper wire).
The specimen holder (honeycomb pattern) should be printed with 100% infill. This reduces floating and improves accuracy.

In PLA with 20% infill, the weight on the scale is less that 50g - so a 200g measurement range should be enough for specimen up to 150g

Put everything together as shown in the CAD Image. Fill the basin (Wanne) with water. The specimen holder should be well under water, but not touch the walls or bottom.
The frame (Gestell + Deckel) is placed on your scale. and should not touch the walls of the basin.

The measurement of density of solid objects works as follows:

1. Measure the object dry (put on top of the "Gestell" - the "Deckel") = m_dry
2. Measure the object submerged in water by placing it on the "Probenhalter" (honeycomb) that is held by wires in the water. Measure m_wet
3. The Volume of the body is V= (m_dry - m_wet) / rho_water
4. The density of the specimen is rho_specimen = m / V = m_dry * rho_water / ( m_dry - m_wet)

Distilled water has a density of rho_water = 0.9982 g/cm3 (@20°C) - tap water is okay for the accuracy we are aiming (add 0.0005 g/cm3 for very hard water)

With this setup I reached an accuracy of about 1% for the density of a 50 Euro-Cent coin (Result: 8.08-8.16 g/cm3 - density of nordic gold: 8.12g/cm2) .

It is important to note, that, especially for denser materials the accuracy will reduce because the measured Volume is in the denominator of the density formula.

This is the scale I used: https://www.amazon.de/gp/aw/d/B09NN31RGP