<p>I haven't tried such a thing, but a speculative answer covering the constraints and expected failure modes may suffice here.</p>
<p>Unless the sheets have squared (rather than rounded) corners, the corners will almost certainly be a problem. In particular you'd end up with a hole right at the middle of the bed.</p>
<p>If the sides aren't entirely square (perpendicular) with each other then you'll have large gaps at one end or another.</p>
<p>As Trish noted in a comment, it's also possible that you may hit problems due to mismatch in thickness between the different sheets, although I'd expect these are fairly well-controlled in the manufacturing process; otherwise I'd expect bed leveling issues even with just a single sheet. If you do hit this kind of issue, it may be possible to avoid it with shimming of some sort.</p>
<p>Assuming you can avoid all of the above potential problems, I would expect what you've proposed to work reasonably well, especially if you're ok with very minor surface defects at the seams.</p>

CC BY-SA 4.0
2020-09-28T18:46:58.667Z
I expec tthe mismatch to be in the area of micrometers or lower, but it would stem from sheets coming from different batches.
Trish
CC BY-SA 4.0
2020-09-28T18:07:50.910Z
2020-09-28T18:07:50.910Z
R.. GitHub STOP HELPING ICE
<p>Aligning build surfaces isn't the main issue with 1 mm thick surfaces when aligning four 200 x 200 mm surfaces to make one 400 x 400 surface.  The main issue is slight bucking at the seams from thermal mismatch.  Using this with PETG tends to tear up the build surface at the seams.  The image shows aligned surfaces.</p>
<p><a href="https://i.sstatic.net/14q3L.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/14q3L.jpg" alt="enter image description here" /></a></p>
<p>The above was a poor design because prints tended to always print on the seams, which are more susceptible to damage when removing the print.</p>
<p>More reliable was to put one 200 x 200 mm surface in the center of the bed, cut the other three in half, and tile them along the sides.  Glue stice helps fill the seams.</p>
<p><a href="https://i.sstatic.net/mC4ea.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/mC4ea.jpg" alt="enter image description here" /></a></p>
<p>The center of the surface tends to wear out first.  In that case only the center surface would need changing.</p>

CC BY-SA 4.0
2020-10-30T14:49:41.140Z
it *also* shows a mismatch of the edges on the lower corner and the top left one has a lifted corner in the center.
Trish
CC BY-SA 4.0
2020-10-27T12:56:39.490Z
2021-06-15T16:35:26.627Z
2021-06-15T16:35:26.627Z
Perry Webb
<p>Of course I'm referring to side by side and not stacking or overlapping.  200 x 200 mm PEI and Kapton sheets are more readily available than 400 x 400 sheets.  I'm wondering if anyone has tried this and if the edges of the sheets cause a problem.</p>

<heated-bed><adhesion>
Has anyone applied four 200 x 200 mm PEI sheets to a 400 x 400 mm bed?
Perry Webb
# Has anyone applied four 200 x 200 mm PEI sheets to a 400 x 400 mm bed?

(Asked by: username_0 on 2020-09-28)

Of course I'm referring to side by side and not stacking or overlapping. 200 x 200 mm PEI and Kapton sheets are more readily available than 400 x 400 sheets. I'm wondering if anyone has tried this and if the edges of the sheets cause a problem.

**Tags:** heated-bed, adhesion

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## 2 answers

### Answer by username_0 on 2020-10-27. Score: 4 | Accepted answer

Aligning build surfaces isn't the main issue with 1 mm thick surfaces when aligning four 200 x 200 mm surfaces to make one 400 x 400 surface. The main issue is slight bucking at the seams from thermal mismatch. Using this with PETG tends to tear up the build surface at the seams. The image shows aligned surfaces.

[![enter image description here](https://i.sstatic.net/14q3L.jpg)](https://i.sstatic.net/14q3L.jpg)

The above was a poor design because prints tended to always print on the seams, which are more susceptible to damage when removing the print.

More reliable was to put one 200 x 200 mm surface in the center of the bed, cut the other three in half, and tile them along the sides. Glue stice helps fill the seams.

[![enter image description here](https://i.sstatic.net/mC4ea.jpg)](https://i.sstatic.net/mC4ea.jpg)

The center of the surface tends to wear out first. In that case only the center surface would need changing.

> **Comments:**
> **username_2**: it *also* shows a mismatch of the edges on the lower corner and the top left one has a lifted corner in the center.  

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### Answer by username_1 on 2020-09-28. Score: 3

I haven't tried such a thing, but a speculative answer covering the constraints and expected failure modes may suffice here.

Unless the sheets have squared (rather than rounded) corners, the corners will almost certainly be a problem. In particular you'd end up with a hole right at the middle of the bed.

If the sides aren't entirely square (perpendicular) with each other then you'll have large gaps at one end or another.

As Trish noted in a comment, it's also possible that you may hit problems due to mismatch in thickness between the different sheets, although I'd expect these are fairly well-controlled in the manufacturing process; otherwise I'd expect bed leveling issues even with just a single sheet. If you do hit this kind of issue, it may be possible to avoid it with shimming of some sort.

Assuming you can avoid all of the above potential problems, I would expect what you've proposed to work reasonably well, especially if you're ok with very minor surface defects at the seams.

> **Comments:**
> **username_2**: I expec tthe mismatch to be in the area of micrometers or lower, but it would stem from sheets coming from different batches.  

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