More Rudder and Anchor Locker Lid Progress

rev. 7-25-2024

Since this post I was asked to investigate injectable foams and injecting epoxy as core fixes.  It can kind of, sort of work, if you are selling the boat soon to someone you hate.

• You can't bond mulch. Since this I saved some core from another repair job and have been growing a house plant in it for about a year. Still going. You need to dig rotted balsa out.
• Rebonding foam core can work if the damamge was the result of a resin-starved joint. Same with balsa. but this has to happen soon, while it is still dry and the core is undamaged. Epoxy works (extra slow cure), but Gorrila Glue can work even better, because it likes a little moisture and it foams and spreads, forcing it's way into the voids. 

 The repairs shown below (four years) are still perfect.

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After drying for 3 days I cleaned up the residue with a cup brush in a cordless drill (a hand grinder has way too much power for working around balsa). I then thickened some epoxy with fumed silica and fitted a new balsa core around the remaining bits. I did not remove 100% of the old core because it was good and because removing it risked more damage to the skin. Tiny bits and wedges were used to fill the gaps and the whole business rolled down firmly.

Clean up your tools and skin using vinegar, which deactivates the uncured epoxy, and then soap and water.

The next morning I used a 120-grit disk on a hand grinder to level the whole business and blend the edge; the original epoxy residue and differences in core product made for irregularities in height, but nothing sands faster than balsa. A few moments with a finish sander evened it up and smoothed the edges; glass cloth must be laid over a smooth surface. I blew out the dust with compressed air and then smeared a bog over the whole surface, filling the gaps and radiusing edges; glass cloth must be laid over a continuous surface without gaps. This was followed while still green with 2 layers of 6-ounce finish glass cloth, covering the core and reinforcing the edge flange, which had always seemed a little weak to me.

The neatest way to trim excess glass cloth is with a razor knife while it is in a leathery state of cure. Finish sand and re-drill holes when fully cured. Two coats of paint will finish  it.

As for the other parts, it's just been a matter of painting, drying, sanding, and repeat. Should be on the water mid-week, since I want the paint good and hard before assembly.

It's surprising how the cost of materials adds up. This totaled just over $200 all in, rudder, cassette, and lid. About 1/2 was resin, and the rest was for glass, core, paint, brushes, and sundry materials. On the other hand, a new rudder assembly, if it were available off the shelf, would $3500 or so. Custom would be more. 

If you like old boats, it really does pay to develop a skill set.