1989 Catalina 22 hull tabbing repair help

[dlochner]

Do not thicken the resin when wetting out fiberglass. Thickened resin is used for filling gaps and holes or for use as an adhesive.

The vertical sections will stay in place, unless there is way too much epoxy in the glass. It will not form a tight corner, all corners will have a radius.

A dewaxer is probably not necessary but it is a belt and suspenders approach. Some solvents are formulated for wax and grease. Denaturated alcohol also works. Acetone is my third choice, it doesn't do all that well on grease.

 

[Chipmunk88]

Ok no more grinding, that's what I wanted to hear. I'm still not sold on the fillet. I'm not sure how I would put one in since there is no corner just a gap. I feel as though I would have to put some sort of backing material in place that I could push the fillet resin. As for cleaning, has anybody tried the method of running water over the cleaned area to look for spots that repel water? Is this reliable? I guess the idea is the areas that repel water must have some sort of grease or other potential contaminants on them. I buy dewaxer. Does sandpaper type matter? I hear anti-clog coating are no good.

 

[Foswick]

Based on your description of there being a 1" gap and your drawing, I'm not sure you want to tab that entire joint. It really isn't completely clear what we're looking at here, but that gap exists for a reason, obviously. Most likely, it is so water (from condensation or slow leaks in the deck or whatever) will flow under the cabin floor. I can't recall what the bilge in the Catalina 22 looks like, but I'm thinking that it is just a depression/well where the keel bolts are exposed. Any water eventually flows down into that well.

But, regardless, make sure sure that, assuming that gap is to allow for the flow of water that you do not block it with your tabbing.

 

[Chipmunk88]

Anyone have a recommendation where to get non-stearated sanding discs, are they nessecary? I am only replacing existing tabbing, there will be no obstruction

 

[dlochner]

I've taken to using sanding screens. They work better with vacuum sanders, last longer, and don't clog. Slightly more expensive upfront, the payback is the longer life.

Assuming the original tabbing was factory installed, the question is what function do they serve? If this was a serious structural concern there would be greater contact between the vertical member and the hull, it would be filleted and tabbed. Since it there is a gap and it is not filleted, the tabbing must not be a serious structural concern. (I suppose it could be serious but a really poor way of dealing with the structural issue, but Catalina is not known for poor building or engineering.)

There are two possibilities that come to mind, the tabbing is there to seal the space and make it usable for storage and/or it serves some secondary structural purpose, perhaps stabilizing the interior pan to reduce any movement and subsequent weakening of the pan. Since the tabbing is failing, some forces have been applied to it that weakened the bond, lending some credence to the stabilizing theory.

As I think more deeply about this repair, I'm intrigued by the idea of filling the gap with some spray foam used to insulate door and window jams. This foam does not expand with the same force some of the other gap filling foams. This would give some backing for a proper fillet, which would provide better support for the tabbing. On the other hand, the tabbing has lasted for 35 years so this might be a bit overkill. In any case the choice of foam will be important, because you don't want to create a hard spot on the hull.

About the wax, polyester resins will not fully cure if they are left exposed to air. That's why finishing resins and gel coat come in a waxed version. Laminating polyester resins do not contain wax, so that they do not fully cure. This allows a chemical bond to form between layers of glass and resin. Polyester resins cure faster than epoxies, thus it necessary to prevent the resin to fully cure until the lay up is complete at which point waxed resin is used. The wax floats to the surface and seals the resin from air allowing it to cure. Epoxy resins do not have this issue.