I recently had to repair my acrylic build platform after I broke it trying to fix a wild curve to the material that had grown worse with time. Even with the extra couple of mm of material I printed to the center of the acrylic sheet, there was still a noticeable bow.
I got it working just well enough that I was able to print a glass frame for my Replicator 2 that I found here. Here it is, clipped in place. It lost about a mm front and back from the bow in my old build plate.
Unfortunately they didn't have 3/16 glass in town, so I went with thicker instead of thinner, and got a 6.5 x 11.25 x 1/4" glass plate. They took the edges off and only charged me $10. There it is sitting on my desk at work. I got it done at lunch time and it was killing me to wait the rest of the day to get home and try it out.
There it is in all it's glory. I used some Sugru to affix the platform to the next frame I built.
You can see how it sits a little high. Unfortunately I only took off 1mm when I scaled it, instead of about 1.5mm. Going to print it one more time and try to get it right. May go ahead and mod it for the missing little bit of space. Once I get it done I will upload it to thingiverse with a nod towards the creator.
The prints this machine makes now are amazing. I had just figured out how to get a glossy print by printing on packing tape with my old build platform and also using diluted, dried glue stick on the surface. Now I just need the glue stick and a good bed leveling before a big build.
Here is what it looks like before and after. It is a night and day difference, and remember, just a few days before this not one of my prints ever came off the machine with a gloss finish.
Here is another.
One side effect that I did not expect, is that the inside of the print is twice as smooth using glass rather than the plastic build plate.
I am calling this a win and wish I had upgraded years ago. It is a little upsetting that the glass plate was not the default on an expensive printer.
I am not going to recommend this upgrade for everyone, but if you want to give it a try, what harm is there in printing one part and spending 10 or 20 bucks for a plate of glass? Especially when the results are like having a much newer, and much better 3D printing machine.