Problem with lacquer finish/Finished table pictures

[mkepke]

So, if I understand what you just said, I can spray another coat of lacquer, over the existing cloudiness areas, and all will look good? Provided I have a low humidity environment in my shop?

Yes..the idea is that the new top coat dissolves the prior coat, providing a pathway for the moisture to escape. The lacquer thinner is doing the work..the lacquer solids are just along for the ride.

But simply spraying an additional coat won''t magically fix whatever ambient conditions gave rise to the blushing in the first place.

Spraying blush retarder (like several people recommended) is probably the 'better' solution since it CAN help compensate for poor ambient conditions by flashing off (evaporating) the solvent more slowly. Assuming you could lay your hands on some.

-Mark

 

[mkepke]

Mohawk Products are readily available at any Klingspor store in Raleigh/Cary or ;Hickory NC Their Factory is located in Hickory NC. They have been serving the furniture industry for more than 75 years in touch-up products ,stains ,lacquers. Forget the Box store ,use a quality product to get a great finish.They also have classes on touch-up.
Bill E

And Klingspor charges like $10 a can (I just checked).

Woodcraft is $35, AMZN $25..I nearly fell out of my chair.

-Mark

 

[Gofor]

So, if I understand what you just said, I can spray another coat of lacquer, over the existing cloudiness areas, and all will look good? Provided I have a low humidity environment in my shop?

Spraying over the blushed coating may give you a decent looking finish, but the moisture laden finish, which is softer than it should be, remains in the layering. It also could just cause the moisture to migrate up into the new top coat.

I have also misted a blushed coating with blush retardant solvent, with mixed results. If the surface is horizontal, you may get away with it, Any surfaces not horizontal will probably sag or dimple if you get enough solvent on it to release the moisture. In every case I tried, it did cause a loss of gloss.

If any of the above occurs, you will end up sanding it all off. My experience has been that removing the blushed coating to start with has been the most economical time, energy, and material wise.

As Fred stated, humidity is the main problem. Not relative humidity as much as the dew point, which is the best indicator of how much moisture is in the air. Related to this is the need for a water separator in your air line. If your air supply is giving you moisture laden air, it may still cause blush even if the room air is dry. Temp is related as the cooler the air, the closer to the dew point. However, raising the temp will cause the lacquer to dry faster, thus increasing the chance to trap any moisture that does occur in the spray. Too high and you get dry spray because the solvent evaporates before the coating hits the surface. A de-humidifier is your friend because it removes the source of the problem.

As a side note: be careful using blush retardant thinner with metallic lacquer finishes. When I was younger, and painted cars as a side income, I painted one when the conditions were like it currently is here. Back then, you could get your thinner custom mixed for the weather condition. After spraying the car, I left to let it cure. When I came back, all the gold metallic in the burgundy coating had floated to the top of the coating on the hood, leaving the entire surface looking like tarnished brass. Needless to say, by the time I had corrected this, I ended up making about $0.50 an hour for my labor. Slowing the drying time can have deleterious results.

 

[joec]

I sanded the problem areas late yesterday with 220 grit and put the AC on 72 overnight. This morning I sprayed another coat and did not have any blushing. I will sand with 400 grit this afternoon and add another coat. Hopefully I will be done with finish after that.

 

[mkepke]

Hey Joe - when you say you sanded with 220, did you sand to remove the old blushed finish down to the raw wood surface before respraying?

Just trying to understand which strategy gave you success.

-Mark

 

[joec]

Without any experience in this, I wanted to start off with the highest grit I could use and get the job done. It worked, but I sanded the problem areas aggressively with the 220. I did not have the problem over the entire work area, as the first coat I had done in my conditioned shop and all was well. When I started on the 2nd coat (outside), the blushing showed up quickly and I stopped. I had the part of the panels and mouldings to sand, and not all of that.

 

[joec]

Just finished this piece that I had all the issues with the lacquer finish.

 

[joec]