Best way to protect a shellac finish from water stains.

[Matthew Curtis]

Ok, so I have a water mark on a shellac finish. A lot of people say to use denatured alcohol to repair the water mark. My question is why not wipe in more shellac to repair the water mark? Shouldn't the alcohol in the new shellac fix the mark? Also what is the best way to protect it from getting more water marks? Is wax the key?

[Mike Henderson]

Ok, so I have a water mark on a shellac finish. A lot of people say to use denatured alcohol to repair the water mark. My question is why not wipe in more shellac to repair the water mark? Shouldn't the alcohol in the new shellac fix the mark? Also what is the best way to protect it from getting more water marks? Is wax the key?
I'm not an expert in repairing finishes, but I can tell you there's no way to protect a shellac finish from water marks. You know how everyone seems to have coasters for drinks? That's because old furniture used shellac as a finish and it would mark from the moisture of a drink. It's also affected by the alcohol in a drink (a strong drink), if someone spilled a drink.

Modern furniture finishes are not affected by moisture or alcohol - you could leave a drink on them for a day - and get both alcohol and water on them - and you can just wipe it off.

Mike

[Lee Schierer]

Try heating the area with an iron. Place a couple of layers of linen towel over the water mark and "press" the towel with the iron. Check the water mark periodically as you heat it. When it is gone you have heated it enough. The iron will vaporize the water under the shellac allowing it to escape.

[John TenEyck]

Not all modern finishes are water or alcohol resistant. I did some testing earlier this year that showed some finishes are damaged by long term exposure to water, like leaving a wet plant pot on a table top, more are damaged by short term exposure to alcohol, and a lot of them are damaged very quickly by ammonia containing cleaners. I did not test any pre cat WB or solvent based varnishes, but of the finishes I did test, solvent based traditional varnishes generally were the most resistant to the chemicals I tested them against.

John

[Prashun Patel]

The reason you cant remove the mark with shellac is that it can take some rubbing to remove the mark. If you do that with shellac, it can get sticky and create ridges or streaks. After you rub out the spot, you can either wipe the whole thing with a dna moistened rag to blend in the spot or you can wipe on a new thn coat of shellac.

[Mike Henderson]

Not all modern finishes are water or alcohol resistant. I did some testing earlier this year that showed some finishes are damaged by long term exposure to water, like leaving a wet plant pot on a table top, more are damaged by short term exposure to alcohol, and a lot of them are damaged very quickly by ammonia containing cleaners. I did not test any pre cat WB or solvent based varnishes, but of the finishes I did test, solvent based traditional varnishes generally were the most resistant to the chemicals I tested them against.

John
Agreed. The waterborne acrylic finishes are not resistant to water. But almost any of the pre-cat finishes are pretty tough.

Also, the white mark is almost certainly moisture under the shellac. It will usually work it's way out but a bit of heat will help. But take that with a grain of salt - I'm not an expert in fixing those kind of problems.

Mike