Pinballs with chipboard ( particle board) i avoid like the plague.... one sniff of water and its goodbye chipboard!

The EM.. MARS TREK has an all partcle board cabinet - youll find most of these games with a crumbling cabinet

Some of the european manufacturers used a poly carbonate type PF that had the artwork on the underside. I believe this is what Mark C is referring to in another thread.
Its extremely hard wearing and because of the print on the underside, PF wear is pretty much negated, plus if it gets cloudy like Mylar does due to wear it can be cut back with T cut to a high gloss again.
RALLY games had this feature as well as many other innovations that were well before their time...


... oh to own a late 60's RALLY game... THESE are my holy grail!

Also - the quality of the timber will dictate the life of the PF - you wont see a 30's pin with flaking and cracked paint because the timber used is of such high quality - some of my 30's pins have hard wood PF's.
Zaccaria pins are FAMOUS for their PF's - REALLy high qualty timber and inks used, youll find most Zacs have excellent playfield artwork.

So to marine ply is used due to the lack of expansion and contraction as opposed to standard ply.
Most ply bought these days is still "wet" and hasnt been seasoned properly