Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh?
#9
  
Gentlemen, the pictures below are Paduak treated with Tung Oil, dried for a week until a clean dry cloth came away clean and dry.  Then, two coats of shellac, then several coats of Deft Laquer (Sprayed).  It's been muggy, and I've had some blush problems.  But they didn't seem that severe.

When the laquer dries, it's shiny glossy beautiful. Come back a couple of days later and...the picture.  Some blue painters tape tore off some small patches (not pictured).  Is this me applying when it's too humid, or is the Tung Oil (Lee Valley real TUng Oil) not cured enough?  And...is there a way out of this that is not sanding everything back down to wood?


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#10
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
(03-11-2019, 08:10 PM)jgourlay Wrote: Gentlemen, the pictures below are Paduak treated with Tung Oil, dried for a week until a clean dry cloth came away clean and dry.  Then, two coats of shellac, then several coats of Deft Laquer (Sprayed).  It's been muggy, and I've had some blush problems.  But they didn't seem that severe.

When the laquer dries, it's shiny glossy beautiful. Come back a couple of days later and...the picture.  Some blue painters tape tore off some small patches (not pictured).  Is this me applying when it's too humid, or is the Tung Oil (Lee Valley real TUng Oil) not cured enough?  And...is there a way out of this that is not sanding everything back down to wood?

I read somewhere that the pigment in Paduak is soluble in shellac.  I have no clue if that might cause the problems you are having; just thought I'd pass it along.  

If you have to start over, I'd strip off the old finish rather than try to sand it off.  Much easier, IMO. You might want to switch to WB lacquer.  Absolutely won't blush.  


John
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#11
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
Go to a real paint store and buy aresol can lacquer retarder. You could also put it into an hvlp, cheap spray bottle, or cup gun and lightly mist it. It may take multiple treatments for it to work and it may not permanently work at all if for some reason your wood or finish under the lacquer keeps emitting moisture after the lacquer dries. I would suspect an old finish was used under the lacquer or for some reason your stock has a really high moisture content. That is barring high heat and humidity issues when you were applying the lacquer.


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#12
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
You could also spray straight lacquer thinner over it, taking it back to liquid state, possibly releasing some moisture. It will set back up within minutes.

That picture, looking it over again, looks to me like something isn't agreeing with something else being on the wood.
I've never agreed with this 3 and 4 different types of finish layed on top of each other.
Steve





 
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#13
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
I've never had good luck with oil on Padauk. Never cured properly.
I've used shellac then lacquer or poly with good results.
I don't know what the tung oil does for the color but the shellac on bare padauk looks good.
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#14
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
Thanks gents.  Will try the mist of laquer thinner and retarder.  I'll report back.  I'm thinking maybe I should have put japan drier on the oil.

The purpose of the multiple coats:  oil preserves the color (internet research) and pops the grain, shellac is the barier to the lacquer, and lacquer of course does what the lacquer do.
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#15
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
Several years ago, someone posted results here of a test they conducted, comparing woods that were finished with oil, then shellac, vs shellac alone.  I don't recall who it was or all the specifics, but the end result was that when using shellac, the oil doesn't really add much benefit.  It's possible to get the grain pop and amber tint from the shellac, without the oil, which could eliminate a step in the finishing schedule.  I don't recall what grade of shellac was used, but I don't think any colorant was added to the shellac, for the test.
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#16
  Re: Oil-->Shellac-->Laquer--> Humidity(??)-->Uh oh? by jgourlay (Gentlemen, the pictu...)
Reporting back:  in the end I used a 50/50 mixture of ethanol and lacquer thinner to strip the finish off.  This process seems to have taken off some oil as well.  I then went back and put 1 light cut of shellac, a medium cut, and will follow today with a heavy cut.  Enough for the shellac to start to gloss.  Then I'll go back over lacquer.
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