How good is a polyurethane anyway?

[Dan White]

I was at Home Depot today but couldn't find any Varathane. I did find spar varnish (marine) and wondered whether that might do the same job as the clear poly but maybe be even tougher against water spills? Any downside to using this stuff instead of poly?

dwhite

[Bill Wallace]

Dan,

I think you have the right idea. Poly for the people and raw for the food prep. I would not wax the tops as it will just cause problems with moisture getting caught in the finish and require buffing all the time. Th only danger os very hot liquids sitting in place can cause some blush but it would take some pretty hot stuff so you're likely OK.

To keep the health department happy, you should find a butcher supply vendor. They will have a specifc wood block sanitizer/conditioner you can use weekly or so.

The smart health inspectors will know that studies have show that wood has properties that actually kill bacteria. Something at the cellular level of wood, for its natural defenses, actually ruptures the cell walls of bacteria so it can't sustain life on wood. Plastic cutting boards actually harbor bacteria in down in the scratches that even a wash with hot, soapy, and bleach solutions can't easily kill.

BW

[Dan White]

I was wondering whether I needed to wax or not. Guess I won't. I'm finding that the best finish seems to be several coats of poly, sanding between each. As someone suggested, I wet sanded the clear poly with 400 grit and it is smooth as glass now. If I want to bring back some of the shine rather than the satin that the 400 grit gave me, I suppose I need to wet sand with

600 and/or higher grits to get the shine I want. Correct? Also I don't really understand wet sanding (why wet?) but I suppose it provides a smoother surface than dry sanding. So if I start with clear poly then wet sand it to smoothen it out and bring back the shine, will it be susceptible to scratching, or show scratches moreso than if I just left it at a 400 grit finish? I'm also going to try out the Sherwin Williams oil poly over the Minwax I've been testing with.

Yes, I've read about this. One theory I read is that the wood wicks away any water inside the grooves of the surface and dries out the groove quicker. The bacteria can't live in a dry environment. The plastic grooves stay wet for a much longer time and allow for bacteria spread. I would guess the tannins (tannic acid?) have something to do with killing bacteria, too.

thanks for your help, Bill.

dwhite