Re: boat plans
Posted: Tue Jan 18, 2022 9:45 pm
Quote: "'18 gage mild steel sheet, primed on both sides. In service, it is constantly exposed to high humidity from the cylinder cocks. It rusted through in four years.''
Primer of the spray bomb variety is the worst protective coating there is, it's porous and holds moisture.
If steel is sandblasted prior to paint, and good quality marine primer and topcoat is used, it will last for many years. The vast majority of surviving hulls of antiquity are steel. I work with 120 year old cylinder cladding and yes it's still viable, but it's been rusted over and the surface is loaded with tallow. These modern steam cylinder oils being suggested are not rust inhibiting. They can print ''SCO'' on the label, but if it does not contain tallow it's not steam cylinder oil. These little 120 year old car engines I work on, nothing is ever rusted together, all bolts loosen as they should, because of the tallow soaked in every crevice, has nothing to do with the steel. Linseed oil will do the same thing.
Primer of the spray bomb variety is the worst protective coating there is, it's porous and holds moisture.
If steel is sandblasted prior to paint, and good quality marine primer and topcoat is used, it will last for many years. The vast majority of surviving hulls of antiquity are steel. I work with 120 year old cylinder cladding and yes it's still viable, but it's been rusted over and the surface is loaded with tallow. These modern steam cylinder oils being suggested are not rust inhibiting. They can print ''SCO'' on the label, but if it does not contain tallow it's not steam cylinder oil. These little 120 year old car engines I work on, nothing is ever rusted together, all bolts loosen as they should, because of the tallow soaked in every crevice, has nothing to do with the steel. Linseed oil will do the same thing.