It’s hard to guesstimate how much I trimmed the tubes on mine as I did it by sight without actually measuring. At the time, I was in a hurry and needed to get a print going, so I just guessed at it and figured that if I got it too short, I’d swap them for some PTFE tubing.
For the feeler gauge, you can grab one of those at your local car parts place. They come in several different ranges of thickness. Be sure to get one that goes down to the smaller 0.002" - 0.010" range, as you’ll want something around 0.005" (0.127mm) or so. Some don’t start until 0.008" or 0.010" or so, such as the valve and tappet gauges, so just be careful to check that and don’t assume it has all of the smaller sizes.
On the gluestick, you’ll want to put it on when the glass is still cold – or at least something below 40C. I’ve found that if you put it on with it hot or even still warm, the glue globs up and doesn’t do right. I found that out when doing back-to-back prints and trying to turn it around before it had cooled enough. It just doesn’t work.
I usually put a thin layer horizontal and a thin layer vertical. I also have got into the habit of always coating the entire glass – too many times I’ve tried to guesstimate where it will be printing only to miss a vital corner or edge of the print.
You can actually use the glue now on the “blue sticker”. It will really help adhesion for ABS, or so I found while experimenting with that while waiting for my glass to arrive. It won’t work as good as glass, but is better than trying to print without glue. As for sprays, like hairspray, to me that’s way too messy. Hairspray leaves a nasty residue all over everything. And that means you really need to take it out (outside even) each time to spray it, and that means releveling the bed every time. With the gluestick, you can clean it down (I use 70% isopropanol and thoroughly clean it between each print) and reapply glue and print without leveling the bed again. Unless you have to do a lot of prying on the print, it will stay level for dozens of prints.
Speaking of prying them loose, with ABS, the natural warping effect really helps that. When the bed cools below 50C or so, prints with a lot of contact surface will almost always just pop free on their own. What is a little counter intuitive is that the larger the contact area, the more glue you need (thicker glue layers). You would think that the large contact area would naturally have more bonding surface, but the warping tension of ABS counteracts that. Where you have to be careful is on prints with lots of small contact surfaces. For example, if you have a print where the majority of the contact area is supports. The typical grid support structure works really well to hold firmly to the glue as it has minimal warpage due to the smaller contact patches (i.e. the temperature differential is less). Yet, the supports can be printed with a moderate gap to the part to make them easy to break free and remove.
As you print more and more things, you’ll start to see what I mean by counter-intuitive with glue and ABS. The most extreme example was when I was printing a piece very similar to the right-end carriage piece of the FFCP that I was designing for another (non-FFCP) printer I am rebuilding. It has a very intricate shape and needed extreme supports no matter how you positioned it. But, I wasn’t thinking about the fact that the contact area was mostly support grids and applied a larger amount of glue like would be needed for a part of similar large size with that large of a contact area. The result was that I had to pull the glass bed off the printer, take it to my workbench, and whack the part with a rubber mallet to get it loose.
When you install the glass bed, you’ll still want to keep the aluminum plate. It will help transfer the heat from the heater PCB and help it to more evenly distribute. As for the “blue sticker”, you have a couple of options. You can rip it off completely or you can just put the glass on top of the sticker. If you remove the sticker, you should put a layer of kapton tape between the aluminum and the glass. That will also help with that temperature junction. If you leave the blue sticker, it will serve the same purpose.
On one of my printers (the one I got used), I completely removed the blue sticker because the previous owner had tried to replace it with a new sticker and did a horrible job with the new one. It wasn’t even and had giant air pockets in it – making it impossible to level and print on. So it had to come off. The other two printers, I just left the blue sticker on and attached the glass with custom printed clips to the top. Though if you leave the sticker on, you will need to account for it in the thickness of the Z-axis shim.
For the majority of print materials, the glass is the best print surface. But there are a few exotic filaments out there that actually works better with the blue sticker – like some of the clay sculpting filaments and some of the investment casting mold filaments. And maybe even NinjaFlex. So, leaving the blue sticker on gives you the option of easily switching to it in the future. I can’t tell any performance difference between the printer without the blue sticker and the ones with the sticker. The glass seems to heat about the same on both configurations.
Another adhesive you may want to try for ABS is “ABS juice”, made by dissolving some filament in acetone. It’s probably no messier than the gluestick. However, it will most likely leave a bit of residue on that side of the print as the acetone reacts with the plastic being printed and with the plastic that was dissolved to make the juice itself, where the gluestick, on the other hand, is completely water soluble and just washes right off.
And gluesticks are actually PVA based and is a lot like printing with PVA support material.
Happy printing!
