How to fix blemish on Blackwood Tabletop

I was having dinner at a friends home last night and looking at this lovely blackwood dining table that has a couple of blemishes to the tabletop.

I couldn't tell what the finish was. The table was professionally made. The finish didn't strike me as being just danish oil and wax since it felt a little harder than that. I'm guessing it may be a sprayed lacquer, but there is no hint of scratching or lifting of the finish.

In a couple of spots there has been some damage that sort of looks like watermarks that has got through the finish into the timber. The owner has no idea what caused the damage.

I only had a poor quality phone to take this pic, but it at least gives an idea of the type of 'bleached' blot problem area. As far as I could tell it appears to be in the timber rather than in the finish.

Is blackwood subject to water marking like this? If not what else might cause this type of blemish, maybe heat? The blotch is more distinct when look from one particular direction.

And the big question... is this the sort of blemish UBeaut's polish reviver might fix? Any other suggestions short of sanding back to bare wood and starting again?

Attachment 360868

If it's in the wood, then the only way to fix it would be to strip and refinish wouldn't it?

Heat marks tend to conform more to the shape of the heat source. I have seen furniture where the finish has de-laminated from the wood, typically starting at a gum vein, but not patches that big.

I'd be temped to say it is a polyurethane finish, simply because it is so common on furniture.

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Originally Posted by Master Splinter

I'd be temped to say it is a polyurethane finish, simply because it is so common on furniture.

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I wondered about that, but wouldn't a PU finish be waterproof?

Water-resistant, yes, but not waterproof. I wouldn't be expecting them to build up enough layers to create a waterproof finish on a dining table.

If that is the blemish I would not even worry about it. Tables get damaged with use. I think it's called patina.

To my eye that looks like a spot caused by left-over PVA in the glue-up or, in other words, a bit of PVA splatter. PVA is a real PIA in that way - no really visible signs beforehand, you sand really well, finish (with anything) and little "resist" spots like that show up. I have just had that exact experience with my Labour Day long weekend quirky project (see the woodwork pics if you are interested). But, you won't see it now because I used a cabinet scraper to scrape back through the poly until I reached bare wood. A general sand over of the rest, overcoat and "voila" no spots!

Thanks all for the thoughts. Unfortunately it is all guess work. The owner assures me that the blemishes occurred while they were away for several months and the home was being babysat by a very good family friend. No idea what happened. (The house sitters also managed to lose the cat :oo: )

Sounds like a total refinish is the answer although I was hoping something simple like soaking with linseed oil or similar would be a fix.

Maybe it was the Cat's fault and it did a runner when it realised what it had done?
The finish doesn't look particularly thick on the wood, so removing it shouldn't be too much of a trial.
I'd suggest a good oil finish to replace it. Heat/liquid resistant and easily repaired. There are several available. Hard Burnishing Oil is my fav.

Regards,

Rob