8

According to Brickset, these parts have always been made of polyethylene, the only difference is that some of the material is plant-based since the Plants from Plants initiative. Can you tell the difference? No! They look, feel, smell and work just like 'regular' botanical elements. This is because, chemically, they are the same. You can safely mix them ...


7

This is a partial answer (or theory). The moulds for most of the basic bricks have been changed over the years to use less plastic while (hopefully) retaining clutch. 2 x N bricks were given thinner walls with 'notches' for the studs. This may have slightly weakened clutch power. 1 x N bricks (and some plates) were given holes through the bottom ...


4

The LEGO Group has been extremely careful about the formulation of all of the plastic parts they manufacture. I do not believe they ever used lead in any of their parts. Decades ago they removed cadmium from the yellow pigments. I have never found that isopropyl alcohol will soften the plastic used for Lego bricks. What will soften Lego bricks is hot water. ...


3

Silicone does not appear to be safe with ABS plastic This sounded like a good idea to me since silicone works well in other extreme circumstances like baking, but the quick research I've done says this is not so smart. I found two general references for ABS compatibility: Plastics International Plastic Compatibility Chart Kelco's ABS compatiblity chart ...


3

While I can't speak of the handling of these parts, the possibility of receiving official replacement parts from TLG is surely zero. That leaves us only the second-hand market, which fortunately offers genuine LEGO replacement pieces, sometimes even in brand new condition. Note though, that even though the brittleness problem might stem from lots of play or ...


2

Generally for this sort of thing the recommendation is a "light machine oil" (the wording from the Hornby Maintenance sheets). These are "non-penetrating" and so won't damage the plastics which might happen with 3-in-1 or WD-40 style oils. This can often be found as "Sewing Machine Oil". Fleischmann (a model railway brand) sell ...


2

I suspect that you used an acrylic paint with a solvent that softens ABS plastic. Your bricks may take quite some time to harden. It's possible they never will.


1

Petroleum based lubricants you need to be careful with, since they can act as solvents. Zhaph mentioned non-penetrating machine oil, this sounds like a safe bet. If you are in doubt, grab a gnawed brick and submerge it in a sample for a few days and see what happens before putting it on your precious train parts. Science! Second hand info: I have heard that ...


1

Sticky paint is usually caused by painting over a coat that wasn't fully dry. If you did not wait several hours after applying primer, that would be the cause.


1

It could be polyethylene or ABS. My guess is polyethylene because it is more flexible.


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