Darkening a Lacquer Finish On Site
Finishers consider the fine points of darkening an existing old lacquer finish with hand-application methods. July 2, 2008
Question
Hello all - I have been asked to darken a light brown finish on a massive amount of interior woodwork. The wood is oak and has been completely pore filled with a tinted lacquer. I do not spray (my specialty is French polishing) so this would have to be a hand applied solution tinting shellac. Glazing with aniline dyes seems way too tricky in this case. They want this done quick and cheap. I’m considering a polyshades approach but would take any other suggestions. I also wanted to add that I don’t want to use polyshades but I am hard pressed to find another solution. I was also wondering if anyone had used Lockwood's oil stain powders to tint an oil based finish?
Forum Responses
(Finishing Forum)
From contributor D:
Polyshades would be one approach - not the one I would choose, but I guess it may work depending on the color the woodwork is and the final color you need it to become. You could sand the existing finish and use a glaze to tone up the color. This technique would be well suited for someone with French polishing experience, since you would be trying to apply an even tone of color with a smooth pad. This same approach could be taken with other products as well; pigmented stains and NGR stains to name a couple few.
Since the woodwork is filled you will be toning everything, grain and all. Depending on the final color, this effect can often resemble a painted finish. Once the toning is done, you could use any number of finishing products, such as de-waxed shellac and a water soluble poly.
Quick and cheap are relative terms. I can usually do things quicker with my spaygun than I can generally do by hand and with much better results. Be careful pricing this job, it could turn into a real problem.
From the original questioner:
I am most wary of this job for the reasons you allude to, but I am curious about what glaze stain products you might recommend over such a finish. I usually work with shellac, tung oil, waxes or the occasional water based finish (for a dead flat-driftwood effect). I’ve done some super tricky glazing with aniline dyes in the past so I think an oil based product would be that much easier - am I too optimistic? Of course adhesion is my primary worry besides streakiness.
From contributor D:
You can try over-glazing with Japan colors and a touch of linseed oil. This is safer than dyes since it's easily reversible if you don't like the result. You can topcoat with shellac, padding lacquer, or wiping varnish.
From contributor R:
Unless your customer is giving you a blank check on a silver platter I would politely pass on this venture. When you said "massive amount of interior woodwork" and "I do not spray" those were just two admissions that made me answer your posting the way I did.
Protect yourself and look after the client’s best interest. Continue the specialized types of finishes your comfortable with. I would encourage you to learn some of the other aspects of our trade but just not on a job like this one.
From contributor C:
Do you know the type of finish that is presently on the oak now? Is the room well lit? Direct sunlight on any portion of the surfaces? How big of a color shift is required - 20% - 50% - more? Are there flat panels, wainscot, raised panels? Get back with more detailed info of what the parameters of the job are.
From the original questioner:
Contributor D – I’m afraid Japan color would obscure the wood too much. Contributor R - I appreciate your input. Contributor C - the color difference is at least 50% from a creamy yellow to a cool dark walnut. The oak is for the most part not quarter sawn, it is dark pored and flat out cheesy looking. The wood is heavily coated in lacquer and waxed with something that was very hard to remove (on a sample shelf). There are raised panels, baseboard-inset windows with shutters and panels below and doors.
It’s in a well lit apartment on the upper west side of Manhattan overlooking central park. It’s a historic landmarked building with tons of eastern light. Two rooms had been previously glazed a dark mahogany and I was able to find areas where the glaze had completely bleached out to the light blond color. Delamination was also a problem (although only when I scratched at it with my fingernail). I am really thinking of passing on the job but as a favor to a contractor who I am currently working for I wanted to provide a good sample to help them bid on the job. But as Contributor R said - sometimes the biggest favor is saying no thank you! I was pessimistic from the start but I wanted to fight that tendency and see if there were any reasonable alternatives that I might provide. I thank you all again for the input.
From contributor R:
To the original questioner: I reread your initial post and it says "darkening a lacquer finish onsite". I also read it as "oak with a pore fill tinted lacquer". I have no reason to doubt that it is a lacquer finish since you’ve alluded to it twice in your posting.
I would be concerned with adding more finish to the existing finish since you might already be at the recommended mill thickness. The last thing you want to do is to exceed that thickness.
Doing so will lead to problems upon problems. Perhaps not right away but sooner than later a finish failure awaits you.
Is it safe to say that a massive amount of interior woodwork would include more than a little floor threshold? That’s just an educated guess on my part.
How long ago was the project finished? Do you know why the customer let the color work go on and on if they wanted something different to begin with? Did the last finisher leave on good terms with the homowner?
From contributor C:
To the original questioner: I agree. From your post it sounds like it should just be entirely re-done or taken out and new installed. There are too many if's - so to say with this one. Could it in all probability come back to haunt you though? Also, have you determined what the coating on top of the lacquer is?
From the original questioner:
As for the finish it softens considerably with denatured alcohol, smells like lacquer and sands white and fluffy like lacquer. It is very thick. As I said it has gone well past filling the pores on some not so refined oak. I did not know that there was a thickness threshold for finishes - not something I usually have to consider. If I recommend that they find a sprayer would that be safer than an oil as far as long term adhesion?
From contributor R:
I’m not so sure a newer finish applied on top of the existing one is such a good idea. The tea-leaves show an adhesion problem. You would be better off to remove the original finish and start over like Contributor C stated.
From the original questioner:
That is not in the cards. The clients don’t want to strip the wood (it would be a great cost). They may just leave it as is otherwise.
From contributor C:
It could be done in a faux finish if prepped really well by a good faux finisher - someone very good with faux bois wood graining. The key would be testing the overall adhesion first and real condition of the lacquer. It might not appear to be cracked or cracking with the naked eye but under light magnification 5-10 power minute cracking may be seen if it exists. If this were properly addressed first the finish could be made pretty sound. Then a color base coat and faux graining could be done over it. From your post you say the lacquer softened when you tested with alcohol – a lot or just a little? Can you find out how old the finish is? I'm asking because the older nitrocellulose lacquer contained what was known in the industry as French varnishes in the 40's, 50's and sixties. These were pre-esterified shellacs added to the nitro to promote better adhesion, gloss, and flexibility to the nitro which does not by itself have those properties. Just as later more alkyds started being used in their place. If the coatings are that old then they are able to be amalgamated to a new knit surface to provide further finish applications. Old lacquers had no worries of mil thickness as today’s do with the copolymer additions - they were not mil sensitive whether for automotive or wood use.
