Patching holes

[Uncle Bob]

Originally Posted by Spot

My copy of Don Casey's book shows patches going into the tapered opening from smallest to largest. Same plates are in the article here: https://www.boatus.com/expert-advice...iberglass-boat


The largest patch first seems to make sense in that there are longer fibers running through the resin that is in direct contact with the old tapered material.

I would tend to think that reconstructing the original layup would be preferable to creating a plug with the material running at an angle to the original. Having said that I guess that the greater adhesion qualities of epoxy would make the method promoted by the salesmen at west systems equally acceptable.

[Manateeman]

Long before the grungy brothers and epoxy sensitivity and long before vacuum pumps, strong fiberglass boats were made with hand squeegees and a number of layers of cloth to give strength to tight turns, small parts and in particular, to spread out loads. Before it was called fiberglass it was silver glass. Washer rollers were yet to be invented. Any small radius or stress point was carefully done with cloth. The layup was always small to large. You don’t need a vacuum pump to achieve high glass to resin ratios. You don’t need it to wet out cloth and multiple layers of cloth created terrific strength.
The illustrations are for vacuum application. I just don’t see the need for this repair. Epoxy lulls people into believing poorly done repairs will be strong.
In boats without a core, BOTH sides should be tapered. It’s not necessary to be exactly half way because the original layup SCHEDULE might not be symmetrical.
It’s really nice if you know how the boat was built but if you wet out the glass with a bit of acetone and pick at the glass with tweezers, you might get close.
Fixing boats with core is far more complex.
Prior to epoxy, a lot of thought and engineering went into wood boat building. The adhesives were finicky and did not tolerate errors...but they worked.
Take for example wooden aircraft...fro British Fighter aircraft to Howard Hughes.
An old Portuguese boat builder explained structural strength thus...look to how God builds trees...he told me... Small inside then every year larger and larger.
Happy trails to you.
Mark and the manatee crew drying hops on the solar panels.