Build plate adhesion issues?

[cliffyk]

I received the Mars Pro build plate I had ordered from Amazon (yesterday-BTW) and upon un-packaging it I found the reason new "Pro" owners are experiencing build plate adhesion problems--it was obvious to me that it (at least the one I received) is FAR too smooth and shiny to possibly perform as required--I don't know what Elegoo's engineers were thinking when they elected to polish it to this extent--they obviously have recognized the error of their ways as the platen on the latest Mars 2 Pro has a sandblasted finish :



For surfaces with same overall dimensions that with a rough finish surface has greater area than that having a smooth finish due to the "nooks & crannies" of the rougher finish, just like English muffins. Here we want the build plate to have more surface area than the FEP to cause cured resin (the same "stuff" at both junctures) stay with the platen and release from the film--as the platen and the FEP have the same basic contact footprint, the platen needs to have a rougher finish in order that it have more surface/better adhesion.

Here is what the new "Pro" plate looks like; damned near a mirror finish, very much like the FEP:



And here for comparison is the "Pro" plate next to the plate from my plain ol' Mars--a proven performer since I scuffed up the glossy powder coat finish with a 320 grit disc in a 5" random orbit sander (not a single platen adhesion problem since doing that last May, though I have ripped up models in adhesion battles between the FEP and the plate):



I did not run any tests with the new plate as I do not care to waste any resin, and I do need to run tests to know it will not perform--this based upon my practical experience with 6 SLA printers from 3 makers ('til I "added 'em up" I didn't realize there had been that many since I began just about a year ago now).

In the morning I plan on either a) scuffing up the new plate with some 220 grit paper, or b) bringing it to a local welding shop and having it sand blasted or glass-beaded with some fine grit media. I am leaning toward b), however being a welding shop specialising in farm equipment they may not be set up to do finer finishes.

i shall return...