OK. Well I really did address this question a lot of times, but once more, maybe I can be more clear:
Plastic works well if you want to make a million of something cheaply, especially small things, but large things shrink a lot. So keeping good shape and dimensions on a large sluice would be hard and the mold very expensive.
But plastic for a large sluice isn't a good choice for the following reasons:
#1 It's price is tied to the volatile oil market.
#2 Most plastics deteriorate in UV light. Those that do not are generally high $ polymers such as polycarbonate.
#3 There are many types of abrasion. Some of those plastics are good at resisiting, others they are not. Here is a list of them. I bet you didn't know there were so many types of wear, or that someone actually classified them all!
TABER Industries: Types of Wear/Wear Modes
Please note that horizontal surfaces suffer more wear, supporting the weight of something, than vertical surfaces (because gravity sucks,) which generally have less forces acting on them.
#4 All plastics have their operating temperature range. Very few strong plastics are not brittle at very low temperatures and at the same time not pliable and deform at high temps like on a hot rock in the desert in summer which can reach in excess of 190F.
#5 I had an ABS sluice and it had a kink in it I never could get out and it never would sit flat. I swore I would never use plastic then and there.
#6 Mining equipment takes abuse. Good mining equipment can withstand it. Not many plastics can take all the kinds of abuse that a miner or prospector can throw at it. I find aircraft aluminum as good or better in most cases (personal experience.)
#7 There is a property of aluminum that can actually enhance the collection of fine gold.
#8 A few people tried to make a plastic Gold Well sluice already, choosing as best they could the best plastic they thought for the job. Both failed miserably as I hear. Perhaps they just chose the wrong plastic, right?
The term vortex sluice as I use it does not apply to a hydrocyclone. It refers to my pocket design. It looks like a vortex. Everyone makes the mistake of believing that my sluice creates a hydrocyclone. It does not. It creates a sophisticated and convoluted eddy. You have a pocket nearly full of material, this does not make a vortex.
