Originally Posted by ncp
tworoto, the patch piece is a curve - you made it straight. Template it first and transfer to the hypalon to cut the exact shape.
Even with the curve, it is still important to mind the warp/weft so you can stretch the material properly.
With stern transverse seams, start burnishing in the middle and work outwards. Typically, I try an exterior repair first.
Glue the seam back together, burnish, then clamp over the weekend. On monday, I return and air test at ~250 millibar. If the assembly leaks, I find a close by handle or logo, and cut in to the tubeset. At the leak location on the inside, I grind away any mastic and grind the surface of the hypalon. Then I patch the boat internally, and apply mastic around my patch.
Then, inside/outside patch, and I place the logo or handle back over my exterior patch to hide it.