add sparkmaker fep foil blog post

input/blog/2023/2023_09_18_sparkmaker_fep.md

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+title: Blog
+post: Sparkmaker FEP foil replacement
+description: A new print surface for the resin vat
+date: 2023-09-18
+comments: true
+parent: 3d-printing
+position: 36
+---
+
+After a bunch of prints a hole appeared in the FEP foil of the resin vat in my [Sparkmaker printer](sparkmaker_repair.html).
+So it was time for my first replacement.
+I bought [a roll of 127 micron FEP film from FEPshop.com](https://fepshop.com/shop/materials/fepshop-fep-roll-127-120x26cm/).
+The old official tutorial video for this replacement is still [available on the Sparkmaker YouTube channel](https://www.youtube.com/watch?v=2HH5ARg0FUU).
+
+First simply remove all screws and disassemble the three frame parts, the old foil and the rubber gasket.
+Clean all parts with isopropyl alcohol.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_1.jpg", "Old FEP film still installed (1)" ],
+    [ "img/sparkmaker_fep_2.jpg", "Old FEP film still installed (2)" ],
+    [ "img/sparkmaker_fep_3.jpg", "Close view of hole in old FEP film" ],
+])
+%-->
+
+You can clearly see the hole in the top right of the vat in the pictures above.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_4.jpg", "Short screws removed" ],
+    [ "img/sparkmaker_fep_6.jpg", "Long screws also removed" ],
+    [ "img/sparkmaker_fep_5.jpg", "All parts before cleaning" ],
+])
+%-->
+
+Cut a roughly matching piece of FEP film and pre-cut the holes after carefully aligning the first four corners.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_7.jpg", "FEP film on middle frame part" ],
+    [ "img/sparkmaker_fep_8.jpg", "FEP film with screws on bottom frame part" ],
+    [ "img/sparkmaker_fep_10.jpg", "Fitting test of two frame parts" ],
+    [ "img/sparkmaker_fep_9.jpg", "All screws in place in bottom frame part and FEP film" ],
+])
+%-->
+
+The proper assembly order is the bottom-most part, followed by the FEP foil, then the gasket, then the middle and top parts.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_11.jpg", "Gasket on FEP film" ],
+    [ "img/sparkmaker_fep_12.jpg", "Bottom two frame parts with FEP film and gasket (1)" ],
+    [ "img/sparkmaker_fep_13.jpg", "Bottom two frame parts with FEP film and gasket (2)" ],
+])
+%-->
+
+I suspect the previous owner (and others in online forums) did not pre-cut holes in the FEP film before placing the screws.
+So material of both the gasket and the FEP film was mangled up and pulled into some of the threaded holes.
+In an ideal world you would nicely cut out the holes in their proper place.
+I simply pushed a screwdriver through the holes in the frame, which worked fine.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_14.jpg", "FEP film now tight" ],
+    [ "img/sparkmaker_fep_15.jpg", "After cutting the remaining parts from the edge" ],
+])
+%-->
+
+I encountered some difficulties putting the long screws back to tighten the film.
+A lot of force was required and I managed to rip out at least one turn of one of the threads.
+But in the end all screws are still holding properly, though this may not be the case for many repeats of this procedure.
+
+<!--%
+lightgallery([
+    [ "img/sparkmaker_fep_16.jpg", "Vat installed back into the printer" ],
+    [ "img/sparkmaker_fep_17.jpg", "First print with new film" ],
+])
+%-->
+
+It seems to work fine.
+No resin is leaking and the first print with the new film didn't have any problems.
+At least not related to the FEP film.