I’ve finished creating the front and back hatch openings, but the front opening is not flat. The hatch itself is perfectly flat, the top and hull sections line up well at the edges (tack welded so far, but not connected). The center of the front hatch hole dips about .25" from the ends. I suspect that as it was curing, the weight of the clamps I used might have made it sag there. Anyone else run onto this problem? Any suggestions on how to correct it before I move forward?
So if I understand where you are in the build, you have not yet installed the hatch sill and spacers, correct? Adding those three layers of plywood around the interior of the hatch hole will flatten and significantly increase its strength. When you get to that stage, do a practice clamp up before adding glue and see how it looks. If it is not flat, you can add a temporary flat surface along the top while the glue cures.
Sill and spacers are glued in place. Last night, I sprayed it down with water and clamped the hatch. In place. It probably won’t do anything, but I thought I’d give it a try. With the clamps in place, it looks perfect :-).
Update: Tonight I used a heat gun on it, and clamped it down. We’ll see in the morning if that made a difference. I am cautiously optimistic.
Tried the heat gun and clamping twice. Meh. Maybe a little better, but didn’t fix it.