I never wanted to be a finisher. I wanted to dovetail drawers, make miters and mortises; to carve, perchance a masterpiece, and then turn it over to another craftsman for that perfect glowing finish. What a dreamer! I quickly discovered that any finisher that good had a year’s worth of work backed up, and couldn’t possibly get to my project before next Christmas.
I resisted learning for years, but in one month, both of the good finishers I knew decided to sell out their shops. So there I was, forced to do something. I spent a couple of hours in each shop, begging for information, then I bought a good spray gun. I spent the most frustrating month of my career teaching myself how to use it. Then I spent the next couple of years learning how many things I could do wrong with it. I once sprayed one stroke with my gun and was able to count 15 things that went wrong:
- It was too cold in the shop
- It was too humid
- The spray nozzle was sideways
- The air pressure was too high
- The material flow was too heavy
- The lacquer-to-thinner proportion was wrong
- The fan control setting was wrong
- I moved the gun too slowly
- The gun was too close to the work
- The cup was too full, and a drop spilled from the airhole in the cup onto the work
- The stain wasn’t dry
- I forgot the “smoothie” (see explanation later in this article) and the lacquer fisheyed.
- There was dust on my work bench which blew into the work.
- There was a strong breeze which blew out my spray pattern
- I forgot to filter the lacquer, which meant I had lumps of flattening agent.
Did you ever have one of those days?
What follows will spare you some of the blind alleys I followed, but if you are innovative and persistent, I’m confident you can find a few blinds alleys on your own.
Atmospheric Conditions
If it is cold or damp when you spray, the lacquer will blush. Moisture in the mix turns milky blue-white almost immediately as it dries, especially in places where the lacquer builds up the most, like along the edges of a tabletop. Blushing usually is a surface phenomenon which often can be sanded off with 400 or 600 grit sandpaper so you won’t have to remove all the finish.
On a damp day, adding a product called retarder to your lacquer diminishes the chances of blushing by slowing down the drying, allowing the moisture to escape before the lacquer hardens. But if it is raining outside, do something else that day. You can’t spray.
If it is very hot (85 or more) the lacquer may harden too quickly, before it has a chance to flow smoothly over the surface of the wood, causing an orange peel surface. This can be sanded out with 400 or 600 grit; again retarder will help by slowing the drying time.
If there is a strong breeze where you spray, it can blow your spray pattern away, making it impossible to get a smooth surface. If you spray in direct sunlight, the wood can get hot, causing various things from inside the pores (thinners, vapors, air, water, filler, etc.) to glassify and expand, blowing thousands of tiny bubbles in your wet lacquer. When the lacquer dries it is full of thousands of pineholes, which more coats of lacquer will not cover and which no material I have ever tried will fill. If this happens, all you can do is to strip off the lacquer and start over. This time, stay out of the sun.
This article will be continued in part #2 of this series.