Woodworkers of MeFi, I got a sticky situation
January 25, 2020 4:46 PM   Subscribe

I have a 20 year old table that has what is politely called patina but is really sticky and gross build-up in addition to the stain/varnish breaking down. Can I refinish the table without fully stripping?

I have a 20-year-old Amish quarter-sawn oak dining room table and chairs. The finish is coming off, and it feels sticky. It also seems to have a build-up that is resistant to removal by wood cleaners. In theory, the catalyzed varnish is supposed to last a good long time, but nothing lasts with children. Anyway, I seem to be having difficulties even getting replies from people who re-finish furniture and the fellow P&C (PTA) members' responses were, "You could get just go to Bunnings and get some stripper, and do it all yourself or maybe get some blokes to help." So here are my questions:

  • Could I just to this method Restoration without stripping
  • Would washing then turpentine THEN gel stain finished with poly be advisable?
  • What would you advise?

So that you know, I only want to do this on the tabletop and if it works parts of the dining room chairs. I am in Australia, and there is one mega hardware chain and so selection may be limited.
posted by jadepearl to Home & Garden (15 answers total) 1 user marked this as a favorite
If it is truly Varnish, try a turpentine, linseed oil, and vinegar wash. See here to determine whether it's shellac or varnish:
posted by at at 5:04 PM on January 25, 2020 [1 favorite]

I had good luck with Formby's Refinishing Kit. Follow the directions exactly. There will be a moment when you'll think you screwed the whole thing up but keep going.
posted by tmdonahue at 5:04 PM on January 25, 2020

Varnish will absorb and release humidity and will crackle and get sticky. My uncle was an antiques dealer and used 1:1 turpentine and boiled linseed oil. Wipe on a bit, rub, wipe off excess. Once a day for a week, once a week for a month, once a month for a year, once a year for life Turpentine dissolves some of the old finish, boiled linseed oil replaces the old finish. This is really worth doing, will revive an old finish.

This doesn't work on polyurethane. All of these products have health effects and are incredibly flammable. The rags must be stored in an airtight container because they really can self-combust. Ventilated space, caution, etc.

Formby's will take off finish. A DIY version is 50% lacquer thinner and 50% denatured alcohol.
posted by theora55 at 6:01 PM on January 25, 2020 [2 favorites]

Response by poster: The finish is modern catalized varnish called Resistovar. If that is helpful. It is breaking down and I am seeing some bare wood in places like table edges. Can I do the turpentine linseed oil combo?
posted by jadepearl at 6:17 PM on January 25, 2020

I'd be concerned about a couple things.
The product you state is not strictly a "varnish". Manuf. states it is resistant to many things that destroy varnish. Will the Formby's kits or turpentine+oil work on it? Is there a place you can test this that wont be obvious?

If you are seeing bare wood, then there are bare spots and areas with finish. Has the wood absorbed "funk" in the bare areas that will still be visible after a "do-over" treatment?

I would not poly over an existing finish without at least doing a test patch. The two products could be incompatible.
posted by rudd135 at 6:39 PM on January 25, 2020

Response by poster: This is what is kind of driving me crazy, that the Resistovar is breaking down at all. It had been stated to me that I would not have to worry about refinishing for decades barring actual penetration of the surface. Which is why I chose this finish over oil rubbed. I will go ahead and test with and try the 50% lacquer thinner/50% denatured alcohol (no Fromby's in Australia) first unless you think Theora55's 1:1 linseed and turpentine should be the first attempt.
posted by jadepearl at 7:01 PM on January 25, 2020

I've treated antique tabletops both ways - with a refinisher and by stripping. Since the finish isn't a traditional old finish and also because there are spots of bare wood, I wouldn't chance it - I'd completely strip and refinish it. It's not hard: YouTube has lots of advice to tell you what to buy and how to use it. That way you can put on whatever finish you want on it.
posted by summerstorm at 7:06 PM on January 25, 2020 [1 favorite]

I don't know what the right substance is but I do know that the rags and brushes you use can indeed spontaneously combust and the advice above to seal them in an airtight container isn't quite complete- they also have to be sitting in water and the container should ideally be metal.

The other option is to lay them out flat on concrete outdoors- like on the driveway far from the house or any plants, spread flat with small rocks holding them down- so the heat can escape while the oil polymerizes.
posted by nouvelle-personne at 8:36 PM on January 25, 2020

I had a table where the varnish went sticky once - even cleaned, it was still sticky. It never stopped being sticky. I would be wary of any refinishing that doesn't involve stripping the varnish first, do a patch test, I suspect just putting something on top of degrading varnish isn't a good long-term solution. I certainly wouldn't do any sort of stain over the top of existing varnish, it will go on unevenly at best.

(Also if you strip it you can choose a finish other than poly, which will never be my first choice because I think it ages so poorly. Source: I do some antique restoration.)
posted by stillnocturnal at 12:39 AM on January 26, 2020 [1 favorite]

It had been stated to me that I would not have to worry about refinishing for decades barring actual penetration of the surface.

Actual penetration of the film is what has happened at the edges, where the finish has been worn away. Penetration doesn't necessarily mean someone driving a nail into it.

Count me as one who thinks the durability properties of conversion varnishes have been oversold at the consumer level. For fabricators they offer significant improvements in efficiency because they cure and harden faster and require fewer coats so the product can be gotten out the door faster. I think that's the real reason the manufacturers like them. And it's true that when applied properly, meaning with strict adherence to the complicated directions, they can be more resistant to solvents (good if you're in the habit of removing nail polish at the kitchen table), more tolerant of some harsh cleaners, and maybe somewhat more scratch-resistant than some options. Unfortunately it's easier to screw up the application... wrong amount of catalyst, catalyst not mixed properly, wrong temperature, wrong wood moisture content, applied over incompatible stain, stain not fully cured before topcoating, multiple coats applied too close together or too far apart, finish applied too long after mixing (when it should've been thrown away), etc., etc. The stuff is unforgiving, and plenty of finishers ignore or dismiss inconvenient directions.

And then there's the rule of thumb that the harder a finish is to damage, the harder it is to fix when it does get damaged.

For your situation, what you should do depends on your goal. If you just want to get rid of the stickiness and seal the exposed absorbent areas then you might experiment with solvents to remove whatever the stickiness is, then abrade the entire surface with moderately fine sandpaper (220-ish grit) and apply a few coats of a wipe-on varnish or polyurethane. But if you can't find a way to wipe away the stickiness, or if you're also hoping to make it look great, then I think you're looking at a complete strip and refinish job. Sorry.

Whatever you do, don't apply any sort of stain (gel or otherwise) unless you're completely stripping and refinishing. Stain is for bare wood. It won't work on top of an existing film finish.

Also don't fret too much over the spontaneously-combusting oily rags thing. If you have a few rags soaked in an oil finish, just hang them over the edge of a trash can and allow them to dry completely before throwing away. For a small refinishing project at home, you're not going to be generating so many that doing this becomes impractical, as it might in a commercial production environment. The problems happen when they accumulate in piles.
posted by jon1270 at 5:39 AM on January 26, 2020 [2 favorites]

This sounds like a good question for the Woodworking Stack Exchange.
posted by klausman at 7:37 PM on January 26, 2020

I wouldn't hang polymerizing finish rags on a trash can because I'd be afraid of knocking them in or something in some bizarre Rube Goldberg series of events. So I just lay them flat on my rough assembly table and they are generally dry in a day or two. Whatever you do the key thing is to avoid a big mass of wet rags. That's what causes fires.
posted by Mitheral at 10:57 PM on January 26, 2020 [1 favorite]

Just a few rags soaked with polymerizing oils can absolutely spontaneously combust within hours. It absolutely doesn't take an industrial quantity. It's absolutely a danger in a residential / hobbyist setting. And draping these materials on a can full of trash that might also burn is just... outrageously incautious. Please don't give dangerous advice on the internet.
posted by nouvelle-personne at 11:07 PM on January 29, 2020

Response by poster: OK, I have decided to get a professional on this since we are looking at a potential hazard in hot conditions and also, "what could go wrong with a DIY wood project with a newbie at the wheel and no workspace?" The refinisher is planning to use:
bc coatings and Croma coatings products and both have polyurethane clears and acidcat clears both are what I use for tables and furniture it is a catalyzed lacquer designed for spraying and furniture
Should this be reasonable stain/coating with furniture for thug children? Will this last? Should I plan for refinishing in a few short years?
posted by jadepearl at 12:50 AM on January 30, 2020

I can’t speak to those particular brands, and he hasn’t specified the exact product or process anyhow. You might ask him about the finish’s spot-repairability, but as i mentioned above, durable finishes are typically difficult to repair.

Regardless of product, there’s nothing you can spray on the wood to give it the toughness of a granite or even a high-pressure laminate counter. The only decades-old wood surfaces without scars are those that aren’t touched much. A table used daily by kids isn’t going to stay pristine. But you should expect it to survive without becoming irretrievably sticky; that’s a chemical problem that shouldn’t happen.

As to the indignant disagreement above about not hanging rags to dry on a trash can, it took me a few seconds to find one recent article in Popular Woodworking recommending the method, and another in Fine Woodworking that recommended more conservative methods but acknowledged it as a common shop practice, which it is. That said, doing it in an area where kids circulate and do unpredictable things probably isn’t the best idea.
posted by jon1270 at 5:39 AM on January 30, 2020

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