Refinishing Restaurant Tables with Existing Nitrocellulose Lacquer
From the original questioner:
I'd prefer not to strip the existing lacquer finish if possible. Attached is a sample of one of the table tops - the flash makes the finish appear lighter than it is, but you can see the top's perimeter/band is feathered in a deeper stain color.
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From contributor H:
You may not want to strip them, but nitro on rosewood will sand off faster than cat fur on pavement! Then coat with spar varnish.
From contributor M:
You have two problems you will need to overcome, maybe three.
1) There isn't a durable product on the planet that I would trust to apply over NC lacquer. If anything, just clean them up, scuff and recoat with NC or CAB lacquer. Not any more durable than it was to begin with, but nicer looking (for a week or two, anyway).
2) If anyone has ever ever used something like Pledge or other silicone-containing furniture polish (likely, in a restaurant), you will get fish-eye. I charge the heck out of refinish jobs for this very reason. You will need some fish-eye killer (Sherwin Williams Silaway is like $50 a quart, but a quart will do more tables than you have time to refinish in this lifetime).
3) The only durable coating I'd trust (providing that you have stripped the easily-removed NC lacquer and resanded) is Waterlox. This is usually only available on the Net or paint stores that can special order it. Waterlox is a tung-oil based polyurethane (not waterbased, as sometimes assumed) and, as far as I can tell, is the best stuff around (because of the tung oil base). Get regular Waterlox, not the marine grade, as I personally think they are the same thing. Can't tell a difference other than the higher price. The problem with Waterlox is curing time. Hours per coat (I'd recommend minimum two, preferably 3).
If you upgrade your finishing (and have good HVLP spray equipment and a good spray hand), use 2K polyurethane (ML Campbell and ICA both sell a fantastic 2-part urethane).
2K urethane is harder, much more chemically resistant than any oil based polyurethane, and much more finisher-friendly. The only downside is cost per gallon, requirement of a spray hood/spray guns, and the fact that you have 15 minutes to spray the quart you just catalyzed or it will gel up in your gun (this is easy to deal with though).
The last thing - charge the dickens out of them just in case you get fish-eye (likely). The Silaway will work in any oil based urethane, lacquer, or 2K urethane. If you wind up overcharging and you get no fisheye, you can refund them if you need to.
From contributor T:
If you're sure it's lacquer and you don't want to strip, wash it with a mild TSP solution and recoat with anything you want. Spar (long oil) varnishes remain relatively soft and may not be better than a short oil varnish in your situation. Waterlox is great stuff and they crow about tung oil, but I believe it's the phenolic resin that makes it great. A polyurethane resin would probably be more durable, though. A conversion varnish or a 2k would be the most resistant to restaurant usage. Water or oil base? Your call.
From contributor G:
I had the impression that these tables belong to the client and he was asked to make them suitable for a restaurant. If stripping is out, you might be able to improve them by using Isolante as a barrier coat protecting the NC and then topcoating with something more suitable.
From contributor C:
Here's what everyone is trying to say The NC lacquer's brittle nature and barely passable bond makes everyone nervous about having it as a base or prime coat on these tables destined for commercial use. If (more likely when) the lacquer begins to peel, it will take your new top coats with it. I have recoated NC lacquer finishes with more durable products successfully, but the heavy commercial use for which these tables are destined makes such a plan risky at best.
That little bit of burnt edging could be reapplied with a spray gun in about two or three minutes per table. I'd resand the tops and refinish with tinted polyurethane. By the way, I am reasonably sure that those tops are not rosewood... Rosewood has quite a different look and would drive the cost of such tables up by at least several hundred dollars each. If sufficient supply could be found at all. I see rosewood lumber currently offered at from $18.75 to $89.00 per board foot (4/4). They could be cherry, maple, birch, alder, etc. - most likely birch.
From contributor J:
I think I would put a 2 part polyurethane on them. The best, and more on the expensive side, is Dupont Emron, but there are a few others that are just as good and more financially agreeable. I use Pro-Line Pro-Thane. They use it a lot in shipyards. It dries very hard and has good adhesion to almost anything. I also use it as a pre-coat to polyester resin.
From the original questioner:
The lumber I believe is Kikor (East Indian Rosewood?) and is a hard, dense wood. The recommendations are really appreciated and I welcome more. I do have an extra table or two to work with, so I will be able to experiment upon researching some of the above suggestions - sounds like stripping/sanding may be the best approach. If I do have to stain, I will have to color match to the pedestal base (which I do not want to get into refinishing). Thanks again.
From contributor R:
It's unfortunate when someone tries to save a buck but ends up paying two in the long run. These tables most likely were built overseas and had an okay finish applied to them. In order to apply a commercial finish to them, the existing finish must be removed and a tougher finish needs to be applied. Tougher could mean a poly or an ester or a CV or a gym floor coating.
Trouble is, the questioner really wants something that he (his client) can't have at this point: "the simplest finish method/material while still creating a good bond and durability." No can have.
My guess is that the tables should have been manufactured overseas and sent over in the raw stage and then finished here in the United States with a more appropriate coating. I know you're interested in presenting a complete and proper job to the client, so have someone strip the entire table including the bases down to raw wood and start over from scratch. Determine what you mean by durability and apply a finish that meets your expectations.
From contributor E:
Here's the deal. It has nothing to do with what wood it is or where it is from. It has to do with the weakest link. Lacquer, at best, protects wood from dust - that's it. Now, have you ever heard of aligatoring? It happens when a coating is applied over another that has already cured. Which is what will happen to your finished product if you put another finish on these tables other than another lacquer.
You must take the previous finish off and recoat with a urethane or polyurethane type coating to be sufficient enough for durability. Do not listen to what anyone else says about recoating with whatever else.
From contributor T:
Whoa! Guess I'm living in the dark ages. It has always been my understanding (and my experience) that there are a few things to be concerned with when recoating with another finish:
1. The existing finish must be clean. An alkaline cleaner like TSP will clean both water soluble and solvent soluble contaminants.
2. The surface must be etched or roughed up to promote a good mechanical bond with the new finish. This can be accomplished with scuff sanding, or the TSP does a nice job of etching many finishes; most notably, shellac and lacquer.
3. You want to avoid coating over a finish that is sensitive to lacquer thinner with a coating that contains lacquer thinner. You can get by with it, but your first several coats need to be very thin. Not a problem here because we're talking varnish over lacquer.
I also avoid putting a brittle finish over a soft one. Again, not a problem here. But if soft over hard is a problem, why do we use dewaxed shellac as a sealer/barrier coat under most anything? And what makes sanding sealer easy to sand?
Stripping would be a better place to start, but it is not the only place to start. Thanks for trying to set me straight but I think I'll stick with tried and true for now.
From contributor E:
After re-reading the original question, I stand by what I posted. The questioner is looking for durability in a restaurant. This isn't bedroom furniture but something that will need chemical and moisture resistance. Lacquer isn't the answer and I'm not aware of any of the big name coating suppliers who promote shellac.
Also, what makes sanding sealer sand so well? It's the talc.
From contributor M:
So far as sanding sealer goes, I only only use sanding sealer if I am using vinyl sealer to seal something in. Otherwise I only spray pre-cat or CV. Sanding sealer is weakened slightly by the talc.
I would never, under any circumstance, spray something like CV or 2K urethane over shellac (I don't even own any shellac except for the shellac that is used to coat one of my prescription medication capsules). No need for it in industrial stuff.
Price it profitably, strip 'em, and recoat with some good stuff - lots of good things recommended here.
From contributor Y:
The simplest thing to do is to sand and recoat with an excellent bar top lacquer - two or three coats. Bar top lacquers such as made by Mohawk and others are special lacquers using coconut resin alkyds to add water, alcohol, and other resistance normal NCs don't have. Scratch resistance will be improved, also not scratching white after 30 days with Mohawks/Behlens. It's not the best answer, but remember, no matter what you use it's going to get scratched, dented, chipped, etc. At least with nitro the ease of repair is nominal as compared to the difficulty of trying to repair urethanes or epoxies, or even varnish and CV or CL, and the main reason I still continue to use the older finishing materials.
From contributor Z:
For commercial use, you should remove lacquer and apply catalyzed conversion varnish over a catalyzed vinyl sealer.
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