Remember the thread about the "stripper tank" with the ugly brown goo in it?
This weekend, I was looking for a _liquid_ paint stripper to help take the old-gas varnish out of my log splitter fuel system.
I happened upon a gallon of "Crown Varnish and Paint Stripper".
It's an evil-looking brown fluid with little gobbets of goo floating around on the surface. It smells mildly of methylene chloride and has toluene, acetone, and "alcohols" in it.
Gummed up metal parts soaked in the stuff for an hour come out spankin' clean, right down to bare metal.
It's DARK coffee brown, and dries sticky to the touch.
I think this is the stuff of yore remembered in the shop stripping tank.
Im learning Chemistry .. The Di-Cloro-Methane ( aka Methylene-dicloride) will eat some plastics like Acrylic , maybe even acrylic paint . It will eat other plastics also .
The Toulene is Methylbenzene and will eat styrene ( foam also ) The alcohols are nothing and acetone dont eat much . But then some paints will come off with acetone ... Getting the pH right ..... HCL to lower or LYE to raise .
funny all this stuff wont hurt wood if you varnish wood !
Varnish can beat PU PolyUrthane for sealing wood . PU can flake off /separate , Varnish goes deep , becomes part of the wood . Spar varnish has UV protect . Shellac is just Varnish that is alcohol diluted . They want to invent somethin to replace the old cheaper better stuff , cause patent ran out .... PolyUrethane goes on thick , so it impresses .... Varnish is cheaper , sticks better , protects better ... ###########################################################
Lloyd E. Sp> Remember the thread about the "stripper tank" with the ugly brown goo in it? >
It will dissolve styrene, polyesters, and to a limited degree aramids.
"alcohols" covers a lot of ground. Furfurol alcohol digests all sorts of organics. The brown color could come from furfurol.
Better luck with a high pH with organic substances like varnish.
Lye certainly will hurt wood, as will strong acids
Nah... "varnish" is (basically) just a natural oxygen-cure polyurethane; or conversely, polyurethane is merely a synthesized version of natural vegetable varnish. Commercial polyurethanes were (and some still are) derived from the same vegetable oils as "natural" varnish.
Just the opposite. Natural spar varnish is damaged rather quickly by sunlight, as are polyurethanes. There's a reason boat builders started adding deep black and red pigments to marine varnishes early on. Sure, they're cosmetically pleasing, but their real benefits are as UV blockers.
Not even close. Shell Lac is the digestive exudate of a small soft-bodied beetle. It is collected from tree trunks in certain tropical countries, and sold as a commodity as dirty bulk lac chunks. It is subsequently steam cleaned, solvent cleaned, and concentrated as either dry flake or heavy lacquer to be further cut with alcohol. The common shellac you see in cans contains 3lb of the dry flake per gallon of finished lacquer.
As I said, not even close.
It doesn't go on any thicker than any other oil based varnish. Coating thickness is entirely up to the applier of the material.
Old natural varnishes, like Copal and Spar are MUCH more expensive than polyurethanes. They take sometimes as much as a month to fully dry and cure to fingernail hardness, and are really touchy about brush marks and feathering lines. People who've only ever used polyurethanes don't even know what a "tipping brush" is....
For most purposes where a varnish is called out, polyurethane is the superior product in virtually every respect.
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