Why is finishing so confusing?  

 

1. Finish cans lie.   Well, soften it a bit if you must, and call it mislead, but really.   They don't always indicate what is inside.  Examples;

• "Tung Oil Finish" - you would think this is tung oil.  Nope, usually it's an oil-varnish blend or a thinned (wiping) varnish with little to no tung oil in it or even as a raw component.   Linseed oil is more commonly used.
• "Water-based Lacquer" - if you have experience with nitrocellulose lacquer, a product that has been around 100 years, you will be surprised that this is really a different product that has nothing to do with traditional lacquer
• "Water based polyurethane" - again, it might have a small percent or urethane resin, but it's mostly acrylic and will look and behave much differently from the oil-based poly you've been using for years
• "Urethane - Oil blend" - well, this one is just a varnish.   Varnish is made by heating (urethane) resins and oil until they become a different product - varnish.   This is like going down the bread aisle and seeing a loaf labeled "flour-yeast blend."
• "Danish Oil", "Antique Oil", "Velvet Oil" etc.   Well you get corn oil from corn, olive oil from olives, soybean oil from soybeans.  We do not squeeze Danes, antiques, or velvet to get these oils, often thinned varnish or oil-varnish blends.

Sometimes the MSDS (now known as SDS) will tell you what the true components are.  A Google search for them is a place to start.   But even then a lot hide behind "trade secret" "proprietary" or jam up simple mineral spirits with a fancy name like "Aliphatic hydrocarbon"    The CAS (Chemical Abstracts Service) number is unique and cuts through all the BS, when it is provided on the SDS.   Again, Google might help.

 

2. Myths.  There are hundreds of myths out there about finishing.   Bob Flexner's book on finishing is full of sidebars on them.   Like all myths, they tend to get repeated and passed down as truth.    Flexner has what he calls the "half-right rule" -- half of what you read or hear about finishing is true.   You just don't always know which half.   And yet the myths persist.  YouTube and Pinterest have accelerated the spread of them.  Abraham Lincoln once said, "Don't believe everything you read or see on the internet."  I recently asked a major manufacturer's technical support group a simple question about one of their products.   Their response was completely incorrect based on what I know about that particular product.  And good luck asking the guy at the big box working in the paint department that used to be a truck driver.

 

3. Chemistry, not physics.  Finishes work by chemistry - solvents, evaporation, polymerization, chemical reactions.  You can't see this happen, but only the results.  When you are woodworking, it's physics.   You can see if an edge is square, if a joint is tight or gapped, if a surface is smooth or warped, etc.  With finish, you apply it and sit back and watch.

 

Some knowledge will help you get around the confusion.

PREZACTLY! All this misinformation makes replying to questions about finishes really hard as well. Don't forget about Teak oil..Bob wrote an entire article fuming (my word) about it. I especially go off the rails on the water borne poly questions...sine they are almost always asked in the context of the product being the same as oil based "poly", without the oil. Then try to explain they are actually an acrylic finish and watch the criticisms mount. But recently "oil modified" or "modified oil" (take your pick) water borne finishes are cropping up (I think Enduro Var is one) and I spent some time trying to figure out what they are exactly, and struck out. That included a few e mails back and forth to Flexner asking about them. They apparently haven't cropped up on his radar yet (though he indicated they really aren't all that new) as a consumer finish.

Edited April 3, 20188 yr by Fred W. Hargis Jr

Thanks for another eye opening lesson! I really appreciate the knowledge.

Just sub out the finish, and keep on building. It would all become clear if we all took a course in Alchemistry.

Herb

Great post - thanks

 

"With finish, you apply it and sit back and watch."

 

I find this the most exciting part - we really don't know what it's going to REALLY look like until the finish starts doing its thing.

8 hours ago, Fred W. Hargis Jr said:

PREZACTLY! All this misinformation makes replying to questions about finishes really hard as well. Don't forget about Teak oil..Bob wrote an entire article fuming (my word) about it. I especially go off the rails on the water borne poly questions...sine they are almost always asked in the context of the product being the same as oil based "poly", without the oil. Then try to explain they are actually an acrylic finish and watch the criticisms mount. But recently "oil modified" or "modified oil" (take your pick) water borne finishes are cropping up (I think Enduro Var is one) and I spent some time trying to figure out what they are exactly, and struck out. That included a few e mails back and forth to Flexner asking about them. They apparently haven't cropped up on his radar yet (though he indicated they really aren't all that new) as a consumer finish.

I was at the theater set build a few weeks ago and someone mentioned "Latex paint"  

I suggested the word "Acrylic."

She responded, "No, it's latex."

I was too busy to give a finishing lesson that she might not either understand or appreciate.  Shrugged shoulders and walked off to do some carpentry.