Polyurethane

busterb • Jan 11, 2016 9:41 am
At Hd ware store guy told me you couldn't use marine grade for things in house. Me. Well it will be used out side and brought in after dry. Still no. I've never heard of this. Maybe that's why I'm kinda brain dead?:eek:
glatt • Jan 11, 2016 9:46 am
I think that's wrong.

There are marine grade paints that contain nasty chemicals to help keep animals from growing on them, and you shouldn't use those in your house, but I think marine grade poly just has UV inhibitors in it to keep it from breaking down in the sunlight. I think it's overkill for use indoors, but perfectly safe once dry.

(This isn't a cutting board is it? If it was a cutting board, I'd do more research to be certain it was safe. But anything that you might touch with your skin would be fine.)
footfootfoot • Jan 11, 2016 10:22 am
Here's the cliff notes on varnish.

Varnish is made from oil and resin and is thinned with some type of solvent. The more resin a vanish has (relative to oil) the harder it will be, and the more oil it has (relative to resin) the softer it will be.

Softer varnishes are often called "Long oil varnishes" and are used primarily outdoors or in marine applications where the wood is subjected to extremes of temperature and moisture. The relative flexibility of a long oil varnish allows it expand and contract without cracking.

Harder varnishes are called "short oil" varnishes and are used for things like musical instruments and furniture. The higher resin content makes the varnish resistant to dings and scratches and wears well but will not tolerate extremes in movement through temperature and humidity chnages as well as a long oil varnish.

Short oil varnish, because it is so hard can be rubbed with pumice or steel wool to dull the sheen and give a satin or matte finish, it can also be polished to create a high gloss. Long oil varnish, because it is so soft and flexible, cannot be rubbed out or dulled with steel wool satisfactorily. Some varnishes have talc added to make them matte, These should be avoided because the talc reduces the strength of the varnish.

Exterior varnishes are sometimes called "spar varnish" Anything you buy in a hardware store that is called spar varnish is crap and will not last very long before it starts cracking and lifting off the wood. To get real spar varnish you need to go to a marine specialty store and expect to pay at least $35 a quart.

Polyuethane varnishes are particularly shitty IMO, especially compared to real varnish.

Good brands are Behlen and Epifanes. Behlen makes a wide range of varnishes, Epifanes is known for marine varnishes.

There are entire books about varnishes.

ETA: Cutting boards.
Never use vegetable oil on a cutting board; the oil won't dry and it will get rancid and gummy. If you feel the need to oil a cutting board (they don't need that, btw) use mineral oil or walnut oil. Walnut oil will actually dry, unlike vegetable oil. Mineral oil will not dry, but it won't t go rancid.
busterb • Jan 11, 2016 11:49 am
Not a cutting brd. and 3 ft. I use mineral oil on mine. It's some wood slats,.maybe the kind that were used in wood louvers. I have 2 under the drain rack at sink. Old sink with drainboard built in. And thanks for info.
Pamela • Jan 11, 2016 6:49 pm
Make double-sure the mineral oil you use on your cutting board is food grade. Baby oil is NOT the same thing at all.
busterb • Jan 11, 2016 8:00 pm
I'll have to check. Thanks
Griff • Jan 12, 2016 7:33 am
Pamela;951094 wrote:
Make double-sure the mineral oil you use on your cutting board is food grade. Baby oil is NOT the same thing at all.


Don't eat oiled babies, got it.
glatt • Jan 12, 2016 8:34 am
Do they make baby oil the same way they make nut oil?
busterb • Jan 12, 2016 9:36 am
Yes cold pressed.
Happy Monkey • Jan 12, 2016 8:19 pm
extra virgin
lumberjim • Jan 12, 2016 10:31 pm
Sick Bastards
footfootfoot • Jan 13, 2016 9:40 pm
Happy Monkey;951201 wrote:
extra virgin

From ugly babies?
infinite monkey • Jan 13, 2016 10:21 pm
Pamela;951094 wrote:
Make double-sure the mineral oil you use on your cutting board is food grade. Baby oil is NOT the same thing at all.


Well you should see polyurethane pam...


;)
Griff • Jan 14, 2016 7:40 am
The cellar has pleased me this morning.
tw • Jan 14, 2016 7:22 pm
Uretha, virgins, bastards, baby oil, cold pressed, cutting board ... is this an S&M discussion?