Saturday, June 04, 2005

Sealing the Keel

With about a week and a half to go before I start full time work, I have been trying to make as much headway on the physical work needing to be done to the hull. We have been going back and forth on how to address the case of the water in the keel. It is mostly dry to reveal there is some rust. Rust in the keel in and of itself is not bad. It is just that should the steel ballast CONTINUE to rust by being exposed to moisture, then it will expand. It is the expansion that we do not want. Therefore, the plan is now to do the following 1. "Pickle" the keel in 12 gallons of rust converter. This converts the oxidized steel (rust) into black iron and basically "stops" the rust (not for good though, should it get wet again, rust could begin again). 2. Drain the converter, dry out the keel with the assistance of flushing 20 gallons of isopropyl alcohol through. The alcohol will dissolve any trapped moisture and will easily evaporate. 3. Put the dust collector vaccum on the keel and pull air through it for a few days to get it really dry. 4. Start infusing polyester resin a couple inches at a time (to limit exothermic temperatures). It is not clear yet if it will need to be assisted by vacuum or if gravity will be sufficient. The resin will have to make its way past the fine steel gravel, to the bottom, in the 30-40 minutes of working time. We are using infusion resin which is supposed to be pretty thin. A "test quart" will be poured in in a 12x12 inch opening atop the keel to judge how easily it will flow. This weekend we hope to take care of steps 1-3, with #4 being done over the course of a few days next week. Hopefully the weather will be relatively dry.


Anonymous said...

Why not use a Low viscosity epoxy resin. Longer kick time and then gravity will have more time to work it's magic.

robert said...

Good question. I hate to say it, but the reason is cost. The expoxies are more expensive than the polyesters. We will need at least 25 gallons of resin to seal the keel. If polyester will penetrate well enough I would rather use that. I am using infusion resin which is pretty thin.

Anonymous said...

Once the infusion resin starts to kick though it will go off with a bang! Careull how much you use because I believe the heat created can cause more problems. Even the epoxy will get really hot if you use much of it.

Do you really think that it will take 25 gallons? Did you measure it with Alcohol?

robert said...

Yes. I did some experiments filling a pint bucket with some old steel nuts and bolts, then filled it with catalized resin. It didn't get nearly as hot as ten ounces of plain catalyzed resin (no steel). So expect the steel ballast will absorb much of the heat. Even then, I will only be loading up 3-5 gallons at a time, letting it cure before the next batch.

Yes, 20 gallons of alcohol did NOT fill up the keel. I was surprised.