Interesting! Never attempted pre-shrinking before but definitely have seen the fabric pull away from the edges when I’m gotten a bit too close with the iron.
Do you have any experience with the shelf life of Stit’s products? I see varying times listed on their website, depending on the item. Almost all of mine are over the limit. Only a couple of quarts of Poly Brush are under.
I'm only guessing here but I believe the plywood is too large. In the photo below there is a flange that the rear window fits into, I would image the fabric was glued to the flange and glued into the flange as well, than a reinforcing tape was applied on top the fabric over the the flange. Section G-G in the attached pdf shows the details of the full scale.Working on pre shrunk fabric patterns today. I brushed thinned Poly Tak on the practice pieces to prevent unraveling.
Even 6 clamps aren't really enough for the shrinkage, this fabric shrinks a lot.
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