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19-Then tie a knot close to the hole, tie two more knots to completely secure it, and tighten all the knots.
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20-Do the same for each stationthe next two stations, then trim off the ends.
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21. There will be 2 loops showing on the back cover.
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23. Spread glue on each side (but not the hollow part), making sure not to get glue in the center. Press down tape on the front, then turn the score over and press down the tape on the backbackcover. The threads will form slight swellings at each station.
With the score still closed, press it under a book or two, until the binding glue has set.
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Once, dry it the score should open flat, without any interference from the taped spine.
Sources:
DIY single sheet bookbinding tutorial / Sea Lemon: https://www.youtube.com/watch?v=04vt8YfT7XM
Single Sheet DIY Sketchbooks - Three Methods - My Thoughts and Process / Arlee Bean: https://www.youtube.com/watch?v=jFb8k9y0C2E
Smith’s sewing single sheets / Keith A. Smith. Non-adhesive binding, volume 4. Keith A. Smith Books, 2001.