|
How to on the Olson 30
Burnish a Vinylester Bottom, like Baltoplate or VC-17
- Spray on 2 coats of Baltoplate and let dry.
- Wet sand with 400 grit sandpaper (knock off the rough spots only).
- Bronze wool polish the surface (I forget the wool grade recommended). [ed. Do not use steel wool, as any little flakes will end up rusting.]
- Finish by burnishing with a piece of hardwood that has had the end ‘fired’ - ie you take a piece of maple flooring, cut an angled tip on it. Then stick that tip into live coals (or hit it with a blowtorch) until it gets a layer of charcoal on it. Rub away the charcoal by rubbing against a hard and smooth surface (like a piece of slate). Then use that on the BaltoPlate.
Notes:
The wool and the burnishing should only be done in Fore/Aft motion.
The idea that you only need to polish the first 6 feet of hull and forward 1/3 of the keel because of Reynolds numbers - is an old wives tale. It is based on drag models scaled up from hull testing in drag tanks. Turns out that Reynolds numbers don’t scale that way - especially in ‘surface boundary’ environments.
We found on the J-24, that going to 1600 grit (on a vinylester epoxy bottom) for the whole keel and rudder, and the forward 2/3 of the boat, made a noticeable difference.
|