Quoted from firebrand007:
As PETG washers are not easy to find in my area, I've ordered polycarbonate washers... I assume they should have the same protective qualities ? I'm planning on putting Mylar rings below as suggested by some.
I'm just now getting up to speed in this forum - just found out my GnR LE should be arriving in September! This is a response to a post 20 days ago.
In the world of thermoplastics, PETG and Polcarbonate (PC) would be considered to be relatively close in mechanical properties, but there are some differences. However, I do believe it's a safe assumption to use PC if you cannot get PETG. Keep in mind this is not an endorsement of either for a solution to the playfield issues, but just a note comparing the 2 different polymers.
PC has higher stiffness (Tensile/Flexural Modulus) and strength (Tensile/Flexural Strength) - roughly 30% all around, assuming you are comparing basic unfilled compounds. You'll want to make sure the PC is clear - there are a lot of different PC compounds. PC has significantly higher impact resistance than PETG. When comparing to other material types (i.e. steel washers) though these 2 polymers would be considered to be relatively close in properties.
Polymer fun facts:
PET (and versions of it) is a member of the Polyester family and commonly used in clothing (fiber) and water bottles. PC used to be used in water bottles but there was concern over BPA (Bisphenol A) being an endocrine disruptor and leaching into the water, so alternatives (such as PETG) started being utilized for water bottles. You may see folks refer to LEXAN - this is one of the tradenames for Polycarbonate (PC) and was coined by GE Plastics, one of the companies considered to have "invented" it. PET is one of the most commonly recycled polymers - please put those bottles in your recycle bin....there are folks out there who work hard to get these back into products!
Every wonder why you see more cracked rear tail light lenses than front? That's because PC is used for forward lighting lenses. Acrylic (cheaper and lower impact resistance than PC) is typically used for rear lenses.
Other plastics questions? Let me know. Unfortunately (for me), I know more about this topic than pretty much anything else and am filled with useless information. Sad, but true.