Originally Posted by Rainh2o2
I did my below water
thru hulls like Hilbert. I did taper it more though on both inside and out. My hull
was about 1 3/4 thick in the spots I removed mine. I drilled out the thru hulls with a 3/4 inch hole saw. Made a plug
and some fiber glass matt. More epoxy then matt. Filed the plug down to fit really snug inside the hole and then epoxied that in the hole. The plug was only about 1/4 inch thick. After the plug dried in I started adding fiberglass
patches and fiber matt in alternate layers. I only had time to add about 5 or 8 layers at a time before the epoxy would start to get to thick hot and sticky. I alternated fiber matt and fiberglass
to improve strength. The matt does well to fill while the glass holds the strenght. I did this on both sides. Smoothed it out real nice on the outside and painted. Inside I knocked all the sharp edges and ridges off and just painted but didn't feather as much because of the mess of sanding
inside the boat.
That' was pretty much my process too. The hull
was quite a bit thinner--about 5/8"--and I had some 12ounce biaxal cloth already so used that and no matt. Took a good number of layers to build up on both sides from the plug to the edges of the tapered hull area. I believe the technique WS recommends is starting with the largest diameter circle of cloth and going progressively smaller towards the center, maximizing the bonding strength of the epoxy/cloth to the existing hull with one massive primary bond.
I used intelux 202 and plenty of clean rags to clean before beginnign the layup
. Nasty stuff. Then WS #407 to fair/finish.
If you go with a slower cure epoxy (like WS 206) there's less issue with the thing cookin while you're in the middle of the layup
. Also depends a lot on ambient-mixing temps. Keep the mixing batches small, only a couple of pumps at a time.
And tons of gloves for sure!! Also plenty mixing containers, stir sticks and chip brushes
at the ready. helps to either have a helper cutting the cloth as you go, or to cut everything beforehand.
It can get messy fast, but otherwise easy peasy.