Recently, I have been buying printed DUPLO bricks to see if we can learn more about their evolution, and if we might be able to date them based on specific mold features.
This is a work in progress.
I am still missing many of the mold numbers, especially the numbers below 100 and/or bricks made between 1980 and 2000.
Preliminary results indicate
- Yes, there is a clear evolution of design
- Molds seem to remain in use for longer than those of LEGO system bricks.
- Some mold numbers seem to have been used twice. (This also happens on LEGO system bricks.)
- On LEGO System 2×4 bricks, the DesignID (here 3011) was introduced around 1985. The copyright mark was introduced around 2008(?). In these DUPLO bricks they seem to be introduced around the same time, but that could be because I am missing so many bricks.
From left to right, top to bottom:
Mold A:
- The first DUPLO bricks had castellated tubes.
- Patent pending.
- No flowribs.
- LEGO logo inside the studs.
Mold 20
- No castellated tubes.
- Pat. Pend erased.
- With flowribs.
- LEGO logo inside the studs.
- The print on this brick (HOTEL) was introduced in 1976.
Mold 28
- No patent pending marks.
- X-shape flowribs.
- LEGO logo inside the studs.
- The print on this brick (POLICE) was introduced in 1976.
Mold 103
- No DesignID and no copyright mark.
- Flowrib under the cross-support only.
- LEGO logo inside the studs.
- The print on this brick (FARM) was introduced in 1979.
Mold 099
- With DesignID and with copyright mark.
- This seems to be a later brick than the 103. Other than the mold markings, this brick is similar to the 103.
- DUPLO logo inside the studs.
Mold 108
- Flowribs in two directions.
- DUPLO logo inside the studs.
Mold 114
- variation on the design of 108.
- The print on this brick (Top Down) was introduced in 2010. I also have a “powered by allinol” brick that was introduced in 2011.
- LEGO logo inside the studs.
Mold 117
- A new design, marked with copyright 2002.
- The print on this brick (a parcel) was introduced in 2004, so it is possible that the mold design was made in 2002.
- Curved flowribs.
- LEGO logo inside the studs.
- Compatible with Quattro bricks because the support between the 3 tubes is raised.
Mold 126
- Bought in 2018.
- Variation on the design in 117.
- LEGO logo inside the studs.
- Compatible with Quattro bricks.
Part 31459, mold 1
- A special mold design and part number for transparent bricks.
- Introduced in 2001.
- LEGO logo inside the studs.
- Compatible with Quattro bricks.
[Original post and comments on Flickr.]