I’m looking for suggestions for a clear semi-gloss finish for maple that won’t yellow. I’ve tried Minwax Polyurethane and Deft Lacquer, both have been deemed too yellow. I’m now considering shellac. I’ve read about “two part” and “water based” finishes. They seem to require more exacting application procedures than I’m used to, and I’m not certain they will produce the desired “clear” finish. The piece is an end table.
Tom
Replies
Shellac is available in relatively clear versions--Super Blonde or Ultra Blonde are examples. You will have to buy them as flakes and mix yourself to get those really light varieties. Shellac doesn't yellow over time.
Waterborne finishes, which are acyrlics, will be even clearer, and also yellow very little over time. I wouldn't say they are particularly challenging to apply, just different than oil based finishes. If you can apply the Deft Lacquer then you shouldn't have a problem with the waterborne finishes.
There is a video on doing just what you are asking about on the subscription portion of the web site. http://www.taunton.com/finewoodworking/subscription/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=32278
Finished that do not contribute to yellowing of wood
You specifically mention poly acrylics but what about poly urethanes?
Do they yellow Unstained white pine?
Tom,
I really dislike yellowed maple. Not only do all oil based finishes and nitrocellulose lacquer impart an amber hue, but the natural yellowing which the wood itself undergoes is not inhibited by these finishes.
My favorite finishes for maple are Cellulose Acetate Butyrate Acrylic lacquer (CAB-Acrylic lacquer) which uses the same solvents and handles just like nitro lacquer and Varathanes Crystal water borne varnish. Both go down "water white," never yellow, don't impart any color to the wood and seem to delay the natural yellowing. Although given enough time, maple will eventually become darker and yellowish under any finish.
Cab Acrylic requires no special handling other than standard spray techniques. The water borne varnish takes some getting used to, but it's really straight forward once you get used to it. It looks slightly bluish and milky when first applied (though not as much as other water borne finishes) and it's impossible to completely prevent bubble formation in the trail of the brush - like all water bornes it seems to act like it has soda water in it. It takes an act of faith to believe it will dry clear. But it does, crystal clear, in fact. And the bubbles almost completely disappear.
The first several coats act as their own grain-raising and sealing steps. I level sand every coat after 24-48 hrs with 320 grit on a sanding block for 5 to 6 coats. Leveling removes all surface imperfections, dust nibs, bubbles, etc and completely removes any uncertainty and anxiety about the quality of the surface.
By about the 6th coat I get a perfectly smooth ground glass look. I let that harden for at least 3-4 weeks and rub out with progressive grits of 400, 600 or steel wool, then 1200. I finish with auto rubbing compound (red), auto polishing compound (white) (either one for a satin finish) and swirl remover for a mirror finish.
It's a VERY hard finish and rubbed out when fully-cured is as pretty as a fine lacquer surface.
Rich
Water based polyuerathane won't yellow. Happy sanding!
Tom ,
I have been spraying lacquers for many years and can tell you several things .
Regardless of which of the non Yellowing finishes you use , there is little we can do to prevent the wood from Yellowing . So now the finish stays clear but you do get some U.V. reaction and such .
Maybe the post cat finishes have better U.V. protection .
I just sprayed some of the best product I have ever used . It was Rudd brand and called Dura Cat , it's a pre cat so it was easy to use layed out like butta , it was in semi gloss and you use no thinner with this product , nor do you use sealer . It is a Vinyl pre cat lacquer that sands nice and builds beautifully .
I used an airless with a 5 15 flat tip and holly moly that STUFF was coming out a lot at a time , much larger tip then normal for me . Oddly enough the finish was flawless and seemed to melt or amalgamate nicely , almost more forgiving then the normal precat Catalast from Rudd as well.
here is a pic of White Oak with Jatoba bead and DuraCat lac .
regards dusty
I use Bona Mega water borne poly. Been using it for years on almost everthing I make. I use gloss on the first couple of coats and then semi-gloss on the last couple or 3 or 4 or 5 coats. On small pieces (picture frames say) I wipe on the first several coats and sand between coats. On larger pieces (dining room table) I use one of those painting pads. Sanding between coats and when cured I rub out the finish.
ASK
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