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Two years ago I sanded back my mid century table top and refinished with varathane water based polyurethane. I placed a 1 1/2 mm thick clear plastic protector over the top.

This has produced what I presume is a chemical reaction and has completely removed the polyurethane from the table by causing it to stick to the underside of the plastic protector. See photos.

enter image description here

I want to know if there are any remedies to melt the existing polyurethane to spread over the missing blotches without having to sand the finish off again. I had to sand quite a bit of the veneer top first time round and don’t think it will survive another sanding.

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  • Hi, welcome to StackExchange. I've had many opportunities to repeat this here (it's a continuing crusade for me) sanding should be the method of last resort for removing finish from furniture, especially when there's veneer involved; this is a great example of why. Just a note for the future in case you want to refinish any more MCM pieces which so often feature veneer; although thankfully it's usually much thicker than present-day veneers tend to be.
    – Graphus
    Jan 29, 2022 at 23:47

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The image is much too small to see enough details.

any remedies to melt the existing polyurethane to spread over the missing blotches without having to sand the finish off again.

No. Only works with shellac and lacquer which remain soluble in original solvents. Because of this they also melt into new layers of same finish.

Possible you can apply new coats of polyurethane to table and white blotches will be filled. I do not think edges of blotches will be invisible but test in one area to see, maybe you will be lucky. If it works:

  • Wash surface with warm soapy water, wipe dry. Rinse with cold clean water, wipe dry.

  • Let dry for some hours or overnight before next step.

  • Lightly sand entire surface with 320 grit so new polyurethane will bond.

  • apply fresh coats of polyurethane until you cannot see depressions of missing blotches. 2-4 coats?

  • Allow finish to dry until sanding produces white dust, 1-4 days.

  • Sand surface flat with 320-400 grit backed with hard block. Do not oversand!

  • Complete with one more coat of polyurethane, all scratches will disappear.

  • Do not place plastic protector until finish has fully cured, 21-28 days!

If you need to remove all Varathane you must use a paint stripper this time.

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