Yet another practical upgrade for the Replicator 2, this one will improve the rigidity of your build platform - and hopefully improve the surface quality of your taller prints.
Only a few days after I got my Replicator 2 I began to notice that the print quality was degrading. Then I started getting cracks appearing in prints and they started breaking apart. Simply grabbing the side of my build platform and giggling it up and down revealed what was causing the problem. The little rubber pads that are supposed to push the acrylic build plate up against the tabs that hold it in place had squashed down, making it floppy. So I cut a few pieces of paper in half and used them as a shim between the acrylic plate and the levelling platform to hold the acrylic plate more securely. Obviously this was only intended to be a temporary fix.
So I have been looking for a better solution and this is what I came up with. Its basically a felt surface saver that has been trimmed, sanded, and cut into segments to replace the squashed rubber pads. Felt is more dimensionally stable and should continue to provide a nice snug fit well into the future.
I purchase these felt surface saver pads at my local supermarket. They can also be found at hardware stores. They have an adhesive back and are normally placed under the feet of chairs to stop them from scratching hard wood floors.
The pads need to be trimmed down to be about 1 to 2 mm high. My old acrylic build plate was 8.5mm thick so about 1.5 to 2mm worked well. However this build plate was warped, so I got it replaced and the replacement which is nice and flat, is 9.3mm thick so only 1mm is needed for this. Starting with a pen, and your middle finger resting agains the bottom edge of the felt pad, rotate the felt pad so as to create a line at about the 1mm or 2mm mark (depending on your build plate dimensions) around the circumference of the pad.
Next get a sharp knife and carefully score around this line by making little incisions using forwards and backwards cutting motions. Keep rotating the felt pad and progressively make deeper and deeper incisions, until you cut the top layer off the bottom. Don't use too much pressure, slice back and forth rather than pushing down, and be careful not to cut yourself. Once you have the 2mm base layer, use some fine grit sand paper to smooth out any imperfections.
Finally use a pair of scissors to cut the pad into four segments (see photo).
Now remove the acrylic build plate and unscrew the levelling platform. If you squeeze if together as you undo the thumbscrews from underneath, makes it a lot easier to remove.
Remove the old pads, by tearing them off. This will leave a sticky mess where the adhesive is left. So use some sticky goo remover to get rid of this. To do this, follow the instructions on the bottle. In my case, I left a few drops of the goo remover on each bit of adhesive residue for about a minute and then wiped it off with a paper towel. I then washed the levelling plate with dishwashing detergent to get rid of the remaining goo remover film - which would otherwise interfere with the adhesive backing on the new pads. I also rubbed the surface down with mentholated sprits to prepare the surface.
The final step is to peal the backing off each of the felt segments and stick them into place (see photo).
Re-install the levelling plate by aligning the bolts with the holes in the platform and pinching the springs down while you tighten the thumb screws. Its probably not a bad idea to add a bit of the PTFE grease to these threads to make them turn a bit easier.
Now that these puppies are installed you will have to run your bed levelling procedure to re-level you build platform. Make sure to tighten the bed levelling adjusters enough before you start to ensure it the acrylic plate clears the nozzle - particularly at the back - otherwise it might get scratched.
Once installed, your build plate should be held firmly in place against the retaining clips. There really should be no play at all.