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designing and building with wood channels my creativity and challenges my mind.
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Showing posts with label finishing. Show all posts
Showing posts with label finishing. Show all posts

Friday, August 19, 2011

Oil-Based Beauty with General Water Borne Topcoats

This post shows how to bring out the deep figure in wood furniture using water-borne finishes, which are notorious for leaving wood dead and flat.  

Introduction:
Water borne topcoat finishes - like Minwax Polycrylic and General Finishes Enduro-Var and Pre-Cat Urethane - are very popular among carpenters.  There are many reasons to choose water-borne.  For one, water borne finishes dry in about an hour, as opposed to traditional organic finishes (polyurethane, tung oil), which require 24 hours to cure.  Water-borne finishes don't smell as bad as traditional finishes, the worst-smelling of which (lacquer) is very poisonous and explosive.  Water-bornes aren't flammable, and they clean up with water instead of noxious organic solvents.  Finally water-borne finishes have excellent resistance to heat, water, alcohol and other solvents, making them appropriate for high-wear applications. 

But water-borne finishes are much less popular with fine furniture makers, for the simple reason that they just don't look as good as their oil or lacquer counterparts.  Water-borne finishes don't bring out the depth and figure in wood at all: what you see before you lay down a water-borne is pretty much exactly what you'll see once the finish is dry (some brands have yellow dye to imitate the look of oil-based polyurethane, which changes the tint of finished wood).  This is very different from solvent-based finishes like polyurethane, shellac, oil, and lacquer, all of which make wood "pop" with chatoyance, and show off the holographic shimmer inherent in many wood species.

Less expensive water borne finishes have poor clarity.  When water-borne finishes first hit the market (before my time, in the 1980's), they all had a bluish cast to them...very unnatural!  Nowadays, cheaper brands (like Minwax Polycrylic) have a yellow dye to combat the blue, but the cloudy, plastic look remains.  More expensive (read: high-tech) new water-borne formulations are less cloudy.  But even the very best water-bornes look flat and dull compared to traditional topcoats.  

The best of both worlds:
But there is a way to get most of the benefits of traditional finishes, while avoiding the majority of the hassles of organic solvents.  This method is the only water-borne one I'll use on my projects, and I happen to be using this method right now, on a table commission for a new pub opening soon in Davis Square, Cambridge.  

Saturday, May 14, 2011

DIY sanding block & Klingspor Sand Paper for Sand Flee

For final sanding and rubbing out a finish, a good sanding block is essential.  These final finishing steps require precision and flatness, and are always prone to accidental "cutting through" on the edges of a piece.  Power sanders are often too much tool, and anyway the final sanding and polishing should be done in a linear motion anyway.

For sanding of profiles, such as molding and flutes, a shop-made sanding block is the only way to get into tight curves and corners.

This post is about how to make sanding blocks for any purpose.  It includes tips from my experience on how to outfit a sanding block for perfect results that are nearly fool proof.

Tuesday, May 3, 2011

Minwax Polyshades vs. Water-Based Black Stain Comparison

Getting a good black finish on furniture can be a challenge.  There are plenty of ways to attack the problem, and I have tried most of them.  Today, I compare Minwax Polyshades black polyurethane, to General Finishes' Black water-based stain.  I'll give you my verdict right up front, in case you don't have time to read this entire post: use a water-based black stain such as General's.  Don't go the oil-based route, and don't use Minwax Polyshades.

I have long preferred water-based black stain for getting my furniture black, for a few reasons.
  1. First, I like the water-based cleanup process (just rinse with water).  
  2. Second, I have always had problems with oil-based black stains, especially if I'm brushing them on, because oil based stains have a tendency to stick to the brush, and it's easy to remove stain from the work while trying to put it on.  This is a problem peculiar to black stain, because with black stain, the goal is usually a completely black finish, whereas with other stains the goal is merely to tint the wood, or bring out the grain.  
  3. Third, water-based finishes, including stains, dry much faster than oil-based finishes, and they tend to flow out more evenly, leaving a uniform finish on the work.