No need to be sorry, your English is just fine.
Shimming in this instance is using something like thin foil tape on the bed to make it a little more level before putting the glass down and clipping it on. I would assume if you had a severely warped bed, you’d need to use several layers in the low spots to try and make it as flat as possible, as the glass will flex a bit too when heated. But if you had a mostly flat bed you might not need to.
this may be dumb question, but why would one need to pul a foil tape before glass? isn’t the purpose of glass to make it flat?
Aah 
thank you very much for the explanation . Nope, I did not shim the bed nor the glass. The glass+magnetic foil+PEI sheet compound is really stiff actually. And the auto bed calibration mechanism for Z-axis is insanely sensitive (It stops “pressing down” the nozzle almost instantaneously. So the glass bed is not being bent during this process any noticeably). I can’t speak if “extreme” cases of warped bed would also need shimming but I would assume that for the most warped bed issue shimming won’t be necessary.
Cheers
Not a dumb question. The glass itself is flat. It won’t make the old bed flat. The glass and metal have different coefficients of thermal expansion. As the bed heats up they will expand at different rates. Plastic expands a lot, metal not nearly as much. Glass has a low coefficient of thermal expansion so it should retain its shape at the temps these beds get too and not flex very much.
These different rates of expansion are why you have to keep the glass clipped in. If they were attached via glue or something permanent, these different rates of expansion would cause the glass to crack.
I was mostly asking about shimming because ideally the print bed is even with the glass bed so that you get even heating across the glass. If you had a very warped bed, when you heat it up it’s still going to be warped with the glass bed on top of it. You might have some gaps in certain spots between the bed and the glass, which could cause issues. Uneven heating and cooling of glass, like when the edges are a different temperature than the center, can cause stress and cause it to flex and/or crack. If these gaps are small it shouldn’t matter too much.
Nice. Are you having to adjust the print bed temps higher? Or is it transferring heat well?
I did try different things:
The latter option (adding glass directly onto heatbed) worked the best, which had me really surprising. I usually set my desired target temp (depending on filament brand it varies for me between 50° and 65°) for PLA and wait additional 3 minutes once temp is reached according display. Then I start printing.
For ABS I set 100 ° and wait about 1 hour to 1.5 hours (depending on ambient temp) to get the thrutheframe chamber (Printables) heated up to roughly 40 ° inside the chamber to prevent warping during and after print process. Than I start the actual printing process. This is waaay more time the glassbed would need to get heated. If you have ever used Ender 3. Their 4 mm glass gets heated insanely quick too.
Cheers
I have glued the glass to heatbed using silicone glue and nothing cracks. But if you’re ok with using clips, I’m ok with that too. 
Silicone is a very soft and bendy material. It allows the thermal stress of the glass to be absorbed instead of trying to keep the glass in shape by force, so it would need a lot more thermal stress to crack compared to a hard glue that is not any flexible after curing.
Nothing has cracked, yet. As @Thrawn pointed out, silicone is flexible and can be a non-permanent adhesive. A rigid adhesive, like epoxy, would absolutely crack the glass depending on how quickly the temperature changed.
Bottom line is bonding two materials together that have very different rates of thermal expansion and then repeatedly heating them up and cooling them down will cause stress on the parts. Unless you’re using a specific low modulus adhesive, they will fail and delaminate eventually. The weaker of the two materials will crack. It’s physics.
That is exactly what I wanted to point out. It means there is an alternative to clips.
Someone earlier suggested re-casting the top surface of the build plate with a thin layer of silicone. You could smear on a thin layer and then use a piece of glass with mold release to create the new flat top. It looks like there are silicone formulations that can cure without being exposed to air, if that is necessary. So ideally, you could cure it in place, at temperature, and then just pop off the glass. Basically, gluing on a glass bed but then removing it on purpose.
This would work if the heatbed didn’t warp more with temperature changes. The silicone layer is not rigid enough to hold planar geometry itself. That’s why we use glass as a source of perfect flat geometry.
The idea isn’t to structurally reinforce the bed, it is to fill the concavity.
Yeah, I hear ya. Me too. They seem to have botched their early handling and now we’re in limbo …
I actually tried a variation of this - I needed thicker tape than I has so I used some silicone tape then alum tape over it. Got fairly flat, but the silicone tape failed to pass the heat through causing a >10°C variation where that tape was. That’s too much for me.
I used thicker tape in the center and tapered out. It’s fairly good until this shakes out.
I understand and I believe it could work for some people. But there is significant number of users reporting the deformation changes with temperature, thin layer of silicone (or any other) filler will never prevent this and you’ll get warped build plate again.
My support ticket status has just changed to resolved.
WTF?
How can it be resolved when BL replacement heatbed is not due to be posted for another 3 weeks or more.
Mine as well. I believe that was automated action.
I have reopened it immediately.
Anyway, thanks for heads up. I wouldn’t even notice, they haven’t sent any notification.
Likewise. What they playing at?
The last line of my ticket was the next update I will get is when they get tracking they will update me.
I have added to the same ticket asking them to explain their odd action.
Same here - both tickets with my warped beds were set to resolved. It seems it was an automated action.
Just put a ruler across my build plate and finally figured out why my models can spin like a top. Placed a support request for a resolution but after going through this god-awful long thread, it looks like I’ll have a long wait.
Was planning on buying two additional X1C’s but that is now on hold.
Yeah that’s tragic. I have two on hold as well, and by the look of things I am hoping for a Bambu competitor at this point
