Looking for advice from someone who has experience in spraying lacquer as a final finish on a big table top, or other large surface.
Although my last job turned out well, I had to correct a lot with rubbing out the finish, as spraying was not the way I would have liked it. If I do this again, I will try something different.
The challenge is overspray, as you move the spray pattern over the table. you end up with overspray on the part which still awaits finish, as well as the finished part, leaving the white dust in it’s trail. With the rate at which lacquer dries, this was a real challenge for me.
Willie
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Nitrocellulose Lacquer is actually the easiest thing to spray since it burns into the previous coat (a so-called hot solvent). It is also easy to rubout, especially table tops where you can wet-sand. If you're fighting dusty overspray you're shooting it way too dry or way too hot. Too dry could be the wrong fluid cap or not enough air pressure, plugged cup vent or you're spraying in the wind? Too hot means the solvent is evaporating too quickly. Try a slower thinner or add retarder. BTW the typical home center lacquer thinners aren't very good so I used to use the cheap stuff to clean the gun and the good stuff for the finish. I like Lily Water-White or Bartop gloss lacquers the best and rub it out to the disired sheen. One trick to get a dry coat to flow out is to spray straight thinner just enough to wet it.
BTW lacquer was once my mainstay but not since I tried Enduro waterbourne lacquer and poly from Compliant Finishing Systems in San Clemente, CA. I can shoot EnduroPoly coats 30 minutes apart and level 3 coats after 2 hours, shoot a final coat, and rub it out with steel wool and Johnson's paste wax the same day. Lacquer is high on repairability but low on durability so you may want to consider something tougher for a table top anyway.
John O'Connell - JKO Handcrafted Woodworking
The more things change ...
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John,
You mention water-based poly in your post. I've tried it in the past and didn't like the 'look' compared to oil-based poly. Didn't give the depth I prefer. I like the appearance of an oil rub followed with a topcoat for endurance. I've read discussions before about using water-based poly over oil. Does this process work well in your experience/opinion?
Bill Arnold
Food for Thought: The Ark was built by amateurs; the Titanic by professionals.
Edited 7/23/2004 3:16 pm ET by BArnold
Good points above, and I would add the idea of changing finishes too. I personally love automotive urethane because it dries slower and levels well with less orange peel. Conversion Varnish is a good choice too, but hard to rub out due to hardness. Can you mount the tabletop upside down in your booth? Then you can spray a heavy final wet coat that will not get trash floating in the finish.
"The furniture designer is an architect." - Maurice DuFrenes (French Art Deco furniture designer, contemporary of Ruhlmann)
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IMHO nitro lacquer is fine for vertical applications such as doors, etc., but if this top is to be used where water or alcohol may come in contact, you may want to try a WB lacquer such as Oxford Ultima Spray Lacquer. Has 100% burn-in like solvent lacquers.
If you still want to use nitro, I'd suggest you spray when it's cooler and/or increase your fluid delivery or decrease the air pressure to your gun. Check your fan control too. Should be about medium. I've sprayed large areas in 90 degree weather and havn't experienced the problem you are having. Un-thinned nitro takes about 10 minutes to flow out and dry to the touch here in Texas in the summer.
Sprayed 10 doors (14" X 31") yesterday and the first one sprayed had just started to dry as I finished the last. I usually spray the edges first, then across the grain, then with the grain to finish. This keeps a nice wet pattern on the largest pieces. To minimize the need fof rub-out, I generally shoot a "flash coat" of 50/50 lacquer and thinner as the last coat. Helps to remove nibs and even any imperfections.
The retarder and the ambient temperature is critical to slowing the drying time to avoid lacquer drying before it hits the surface. This situation is exacerbated if you are using a turbine vertical rig which produces hot air. There is one other technique that can help particularly when spraying vertical surfaces with your first coat: hit is with a light coat and then immediately lay down a heavier coat. This will help prevent slumping.
Doug
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