Repair Oak Table Finish?

[Al Launier]

I have an oak table that has been in the family for about 15 years. As far as I can determine (???) it was finished with a clear polyurethane semi-gloss(???) finish.
We recently had a guest who placed his hot coffee mug on the table w/o using a coaster. There is now a circular mark(s) which I think may have been the base of the hot cup affecting the polyurethane.

What to do? I thought rather than go at this with absolutely minimal finishing experience I’d ask the talent on this forum. I suspect my wife will probable want a new table if I can’t pull this off, so there’s some expense riding on this.

I was thinking of doing the following:

1. Mask off an area significantly larger than the affected area to allow for some “blending.
2. Use mineral spirits to remove furniture polish that my wife applied hoping to “bring it back”.
3. Lightly sand the existing polyurethane without penetrating (???) beyond the polyurethane to the wood
4. Lightly apply some wipe-on poly.
5. Let it set for a few minutes (5-15).
6. Wipe off excess in direction of grain, fairing off into the unaffected area.
7. Let dry & repeat as required.
8. Apply furniture polish to regain previous gloss.

I may be all wrong with this approach, so please feel free to criticize & add your recommendations.

Thanks for your help!

[Al Launier]

Any critiques?

[Phil Mueller]

Years ago in a furniture refinishing class, it was recommended that you first try very light dabs on the water mark with a soft cloth dampened with finger nail polish remover. The idea is to loosen the finish to let the air/moisture out that is causing the "ring". Dabbing only, it leaves a bit of finish on the cloth that is then reapplied when you dab.

I've done this on a number of pieces with satifactory success. It may leave the sheen a bit duller, which can be polished to a uniform gloss.

[Karl Andersson]

Before you refinish or use abrasives or solvents, try ironing it out - get a clothes iron (empty the water out) and some 100% cotton cloth (old T shirt, pillowcase, etc- but 100% cotton). This works on some finished to evaporate out the water causing the ring - especially if it was caused by a hot mug or object. Place the cloth on the stain and start with the iron on its lowest setting- iron back and forth on the cloth over the stain, checking to see how it's doing. Gradually increase the heat, checking regularly. if the cloth starts grabbing, it's too hot and time to switch to the other methods.
good luck,
Karl

[Jim Becker]

If the methods mentioned to remove the rings don't work, I'd personally refinish the entire top so that the whole thing looks uniform.

[John TenEyck]

Sounds like the hot mug melted into the poly, yes? If so you will have to sand it smooth, as you described. Whether you can do that before hitting bare wood is hard to say, but worth a try. Even if that's successful I think it will be hard to feather in new poly AND get the color and sheen to match, but again it's worth a try. Your back up plan should be a full stripping and refinish. If it comes to that, it will look as good as new if you do a good job.

John

[Bill White]

Make the "guest" sand the top.
Bill

[Von Bickley]

If the methods mentioned to remove the rings don't work, I'd personally refinish the entire top so that the whole thing looks uniform.

I agree with Jim......

[Al Launier]

Thanks for the suggestions Guys. My preference would be to remove the section of table top that has the affected area and sand/refinish to match the rest of the table. However, my wife is adament about not doing this (obviously wants another table), but I refuse to buy another table until after I've given it a try.

I do think a hot mug melted a bit into the poly, but my wife applied furniture polish to the area thinking that might help - still there.


So I'll try removing the polish with mineral spirits first to "expose" the poly.
Then try the "easiest" suggestion first starting with Phil's suggestion.
If that doesn't work, then it's Karl's ironing procedure.
If that doesn't work, I'll proceed from there.

[Al Launier]

Happy Wife - Happy Life!

Tried the following:


50% White Vinegar 50% warm water to remove the furniture polish. Gloss remained.
Mineral Spirits to remove the furniture polish. Thought it might have removed it, although it still looked glossy. Tried a hair gun at low setting for 10 minutes to hopefully evaporate any water that might have been trapped in the poly. No apparrent effect.
Tried Denatured Alcohol to see if that would remove the polish. Not only did it do that it also removed the water marks. I'm now going to have my wife reapply the furniture polish after waiting a while to make sure everything has evaporated.


Out from under the gun at last!

Thanks again for your suggestions.

[Prashun Patel]

Are you sure that table was finished with polyurethane? Or might it possibly be shellac?

And yes, Happy Wife = Happy Life!

[Jim Becker]

...but I refuse to buy another table until after I've given it a try..

What is this "by another table" thing you speak of?? :D

[Al Launier]

Jim, I suspect you and other married individuals know what i speak of. :rolleyes::D

[Al Launier]

Are you sure that table was finished with polyurethane? Or might it possibly be shellac?

And yes, Happy Wife = Happy Life!

Prashun,you may be right, but actually I am not knowledgeable enough about finishing to know. I'm a rattle can guy, so far any way, with no spray equipment, or large enough projects or spray area large enough or controlled, to warrant spray equipment. I do think however that when I applied the DNA, and if it was shellac, wouldn't the DNA also melt the shellac off the surrounding the water marks? It didn't appear to affect the finish at all except to remove (evaporate) the water marks.

[Prashun Patel]

In fact, that is exactly the way to repair a water mark on a shellac finish. The DNA melts and reblends the area. If it's done deftly, it will not affect the sheen.

For future ref, that info would have greatly affected the advice you got. It would have been a shame if you did not randomly check DNA, and then had to strip the table. One of the beauties of shellac is that while it can be prone to this kind of damage, it's easy to repair. We should have taken a queue that this might be something other than 15-year old cured poly when you first said a hot mug bottom caused a white ring. I don't suspect cured polyurethane to be so sensitive. But, I could be wrong about that.

[glenn bradley]

Jim, I suspect you and other married individuals know what i speak of. :rolleyes::D

I believe one of Jim's posts years ago was the first time I ran into the acronym SWMBO (She Who Must Be Obeyed). :D

Since a new table is a possibility you are free to take a whack at it. Try an inconspicuous spot and put a drop of DNA on it, count to 20 and rub it off. If it melted the finish, your top coat is shellac (although not likely on a commercially finished dining table if that is what you have). If it is poly, the repair becomes more fussy than a total re-finish IMHO. Strip it, finish it and move on :).

[Al Launier]

Looks like I was lucky as I left the DNA on for only a few seconds. I had just read Bob Flexner's book "Wood Finishing 101" & read his article on "Easy Finish Repairs". Since nothing else was working & I wasn't enthused about stripping/sanding/refinishing to match the other table sections I decided I had nothing to lose if I tried a quick shot with a lightly DNA damped cloth. I was surprised it worked, and so quickly. Immediately afterward I wiped it with soap & water to remove ant residual DNA, then let it dry for a few hours & re-applied the furniture polish. It now looks just like the rest of the table. Mission accomplished ..... as small as it may be.

[Steve Schoene]

If the table was made commercially the finish is not polyurethane which only used by amateurs, except for some two part (2k) mostly used in Europe. Its most likely a lacquer of some sort.

Finger polish remover is a stronger solvent than needed. I'd use denatured alcohol or even 90% isopropol alchohol. Wipe lightly just dampening the surface, not wetting it. It may take several passes.