I have a question on spraying water based lacquers. I know that with solvent based lacquers that the after the first coat the subsequent coats dissolve into the first coat and then build up the thickness of the lacquer. Does water based lacquer work in the same way or is it like applying a coat of polyurethane and then needing to fine sand it to get a surface to adhere to?
We get to soon oldt und to late schmart
Replies
The only wb product I have recently seen claim the ability to "burn in" to the prior coat is "Ultimate Spray Lacquer (USL)", a water borne acrylic from Target Coatings http://www.targetcoatings.com. I have limited exposure to different wb finishes, but most have a window of a few hours during which another coat can be sprayed without having to rough up the last coat.
I've used USL and have had good results. A previous post mentions that subsequent coats must be applied within a couple of hours to get total burn in. The last project I did had about 12 coats on it applied over the course of several days (6). As far as I could tell I got good burn in. I rubbed out the surface and had to have cut threw at least the last two or three applications and I didn't notice any witness line.
I have recently switched to using Target's Ultima Spray Lacquer (USL) and its claim of 100% burn in is only true if the coats are applied within about two hours of one another.
I'm sold on the USL. The link below has write up of my experience with it, so far.
http://rlmillard.typepad.com
Rob Millard
Rob,
I've also recently started using the USL and find it easy and forgiving. I prefer a rubbed semi-gloss or satin sheen. Are you using their high gloss material and rubbing to your sheen of choice or are you using the canned satin, etc.? I haven't found the method yet to knock down their gloss enough to suit me. I'd be very interested if you have.
I have not used anything but the gloss.
I'm still working on some of the rubbing out details. The last one I did, I let it cure for 5 days and used 1000 grit paper to level the surface. I then brought up a nice gloss with rottenstone. In the future, I'm going to try using just 1500 or 2000 grit paper and skip the rottenstone, for a slightly duller sheen. So far it has been very easy for me to match the sheen of the shellac finish I use on formal pieces. I had a difficult time achieving the same effect with the varnish I was using, which could look cloudy with anything but a high gloss.
Rob Millard
http://www.rlmillard.typepad.com
Just a question for you! don't you find that water based finishes lacure, poly, whatever, give a duller sheen than oil based products? do you apply something to liven up the patina? oil, varnish etc.?
my personnel experience has been good (with water based poly) but I do find it a bit duller and was wondering if there is a cure?
ChaimMake your own mistakes not someone elses, this is a good way to be original !
Chaim,
When I first used a water based product about ten years ago it was cold and dull. Last summer I tried a water based polyurethane, and it was still a little cold, but very clear ( I think a few drops of a golden brown dye would have warmed it up). The Ultima Spray Lacquer has a much warmer tone and imparts surprising depth on it own. Still, I don't think in most situations I'd want to use it alone, instead I use oil and or shellac accentuate the grain.
I did use it by itself as a finish on the candlestand top shown at the link below. The mahogany veneers on the top of this table were so "alive" that the USL looked great right over the raw wood.
http://americanfederalperiod.com/Candlestand.html
Rob Millard
Thank you for your reply I've mostly been sticking to shellac but I used water based poly over a knotty pine table top and a set of stairs in my home ( I should say the stairs!)
The table top was nice and looked clear and thanks to the kids the stairs could use another coat already (about a year of hard use!) so no complaints other than the lack of... hm...Pazzaz! yea that sounds right!
ChaimMake your own mistakes not someone elses, this is a good way to be original !
Rob, the description of your process in the note was very helpful. Coincidentally my first order of Target filler and USL is ready to be picked up at the distributor (I previously used ChemCraft products) and you nicely addressed several of the items I was wondering about. Thanks again / Al
Rob -
You mention a two hour window for burn-in.
From the Target website:
"USL is the first water-based lacquer to generate 100% burn-in regardless of the age or cure time of the previous coat. Even more remarkable, we are seeing burn-in into cured nitrocellulose lacquers and other less chemical resistant finishes. "
I've been using USL for 4 years. IME it really does burn in as they say. I've sprayed it on old nitro surfaces with equally fine results.
There's no need to rush with the next coat :)
Ed
I did quite a bit of testing with the USL before I used it on an actual piece. One of the things I was most interested in was the burn in, because the witness lines on the varnish were a major headache.
I became a little suspicious of the burn in claim when the instructions said to sand if allowed to dry more than 8 hours between coats. I made a test panel where I let a coat dry for about 3 hours before applying an additional coat. I will admit that the resulting witness lines weren't nearly as pronounced as with the varnish, but they were there. Also, the excellent leveling properties of the lacquer made a heavy sanding unnecessary, which made witness lines unlikely (I really had to sand heavily to create them).
Oddly a gallon can of the USL I bought later, has no such warning about sanding after 8 hour dry time; it says sanding is unnecessary between coats, which is what one would expect with a product that burned in between coats. It also has a warning to stop spraying if the previous coat turns cloudy; a warning that was absent on the first quart can I bought. I had not bothered to read the instructions on the new can when I got it, but in preparing this reply, I wanted to check to make sure my memory of the sanding information was correct. I was very surprised to see the instructions didn't match on the two cans purchased only a short time apart.
I'm going to make test panel with this new can to see if I get the same results.
Rob Millard
http://www.americanfederalperiod
Edited 4/6/2008 8:38 am ET by RMillard
I just sanded some cutoffs from old work to look for witness lines and found none.
The finishing sequence for the test cutoff: 3 coats of gloss USL 30 to 60 minutes apart, overnight drying, sanding with non-stearated sandpaper, followed by a fourth coat of 'satin' that day or the next. The sample was finished 6 to 12 months ago.
USL does cure slowly. A week after finishing I can still scratch the surface if I'm not careful. A purely speculative thought: I wonder if the burn-in takes place over a long period of time?
My container instructions include the cloudy (I think they say milky) warning. The can was purchased within the last year.
Ed
sfmc,
I've sprayed Varathane's Crystal Clear Diamond waterborne straight out of the can, with second and third coats up to 3 days later with no adhesion problem whatever. It doesn't "burn in," but it adheres well.
But I ALWAYS level sand between coats with 320. The sanding doesn't always abrade the entire surface, just gets rid of dust nibs, and the highest rough spots. The abrasion helps with adhesion, but adhesion occurred in the many areas that had no abrasion "tooth." Level sanding is the easiest way to assure trouble-free results.
It's an act of faith to spray (or even brush) many waterborne products as they go down milky white or milky-blue in color and certainly don't look clear. But they cure to a water-clear appearance. The Varathane product rubs out as well as almost any varnish I have ever worked. And many of the other other brands do just as well.
Spraying is the only way I can ever get waterborne varnish to apply without bubbles or foaming occuring. The bubble trail that occurs in the "wake" of the brush drives me nuts. Even with careful spraying a little bubbling action takes place after the finish hits the surface. Most of the bubbles disappear as curing proceeds, or are removed by level sanding between coats.
Rich
Edited 4/5/2008 9:27 am ET by Rich14
Water based lacquers are in fact an acrylic and go on in layers like polyurethane or any other material that does not use a "hot solvent" base. When sanding between coats, do not use stearated sandpaper or steel wool. The first can cause adhesion problems and the second will leave rust spots if any shreads of steel remain on the surface. Cleanliness is very important with water based materials.
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