After LEGO introduced the new brick design with the tube connection in 1958 they continued to search for improvements on their product. One of the main problems was that the CA plastic tended to warp over time. I think this is the main reason that LEGO had already stopped using CA for several items such as their 700e baseplate (maybe they were using polystyrene?).
Around 1960 BAYER was the supplier for the CA “cellidor” plastic. When LEGO started to search for a replacement material BAYER became involved. The “old logo BAYER bricks” were probably produced as a part of their efforts to determine the best replacement material. Eventually “Novodur” ABS was chosen as the replacement for the solid colored parts. Because raw ABS has a milky white color, Polycarbonate was chosen for the transparent parts. ABS has been found in LEGO sets since 1963.
Logo: Old logo.
Material: Cellulose acetate (CA) and Acrylonitrile butadiene styrene (ABS).
The 4 bricks in the middle are ABS, the others are CA.
Inner ribs: Bricks 1 to 10 have a faint line on the long side, bricks 11 to 20 have a faint line on the short side. The line is more visible on my ABS bricks than on my CA bricks.
Inner tubes: with rounded bottom.
Flowrib / center line inside top surface: No.
Mold pip: on the corners of the bottom edge on the short side. Some of the bricks have 2 mold pips.
bottom left: nr 1, 3, 5, 7, 14, 16, 17, 18, 20
bottom right: nr 4, 6, 8, 10, 11, 13, 15
bottom left and right: nr 2, 9, 12, 19
The pip position of nr 17 is odd, because it breaks the symmetry of the set.
Mold numbers: 1 to 20.
- The mold number is positioned on the short side opposite to the mold pip.
- Number 3 is upside down.
Intellectual property protection: Pat. pend.
- BAYER test brick, not for regular production.
- Found in both CA and ABS plastic
- There seem to be a lot of repeating mold errors, but often these are not found in the same lots.
– Number 1: broken bottom right stud;
– Number 5: broken tube
– Number 14: broken tube with “arrow shape” hole in top
– Number 15: broken bottom left stud
– Number 16: broken tube
– Number 19: broken 2nd row left stud
- Slightly shortshot bricks also seem to be common, probably for all mold numbers.
Colors known: a huge range of colors has been found, including transparent bricks with glitter.
- Did Bayer produce test bricks before they started to search for a new material (as quality test of batches of material sold to LEGO).
- Is the BAYER involvement in the search for the new material confirmed or suspected?
- Were BASF and Courtaulds (Wrexham) also involved in the replacement of CA? Did Bayer know about their efforts?
- Can we date these bricks more exactly?
- Were the CA transparent bricks replaced at the same time as the solid colored bricks?
- What specifications were set for the replacement material?
- Which materials were considered?
- Which tests were made on these bricks?
- Why do we find them in such a huge range of colors?
- Why do we find more colors in the “old” CA than in the “new”ABS?
- Why are the studs on mold number 1 and 14(?) broken so often?
- Why do these bricks not warp like other CA bricks made in the same time? What is different in this material/these materials?
[Original post and comments on Flickr.]