Removing Black Dye and Applying a White Coat
Bleach is good for removing dye, and shellac makes a good barrier coat before topcoating. August 8, 2008
Question
I stained several feet of 1 x 2 inch maple profile with water base aniline black, but today I discovered that they are supposed to be sprayed with white water base lacquer. Does anyone have a suggestion or just should I start from new raw wood? I'm thinking about sanding it and spraying some primer but I'm afraid that in time the remaining black in the wood will migrate to the top.
Forum Responses
(Finishing Forum)
From contributor A:
Good old Clorox bleach straight from the bottle should take 95% of it out and a good sanding will get the rest.
From contributor B:
Contributor A is right about the bleach. If the Clorox doesn't do it, get pool chlorine. It's five times stronger, but be sure to wash it with water after the bleaching is complete.
From contributor C:
No matter what other steps you take (bleach, etc.) the best chance you have at permanently keeping the black out of the white topcoat is your primer. The best primer for all of these problematic situations we all run up against from time to time is BIN white shellac primer from Zinnser. Throw a few coats of that then your waterborne topcoat. I wouldn't be too concerned.
From contributor D:
I agree about using pigmented shellac. It does a great job of blocking bleed through. Even clear shellac as a sealer coat before your regular primer does an excellent job. I only like to use one coat of the pigmented shellac though. I find it sands easiest and has surprisingly good fill. With an extra coat or two, it's not as easy to sand and takes longer to dry/cure. If one coat of the pigmented shellac doesn't provide a flat, smooth base for the white waterborne lacquer, then I'd use the primer that goes with the lacquer over the single coat of shellac. If it's a decent product, it will build well and sand easily.
From the original questioner:
Thank you for your suggestions. I will follow your advice. I think it makes sense.
From contributor E:
Shellac sounds like a good idea. If it works at all then why waste the time with bleach and sanding? If these things are necessary then why waste time on the shellac? Some waterbornes require the shellac to be dewaxed. It might not matter on what you're doing but of course it's worth finding out.
From contributor F:
Some waterbased anilines also go into solution with alcohol. The pigmented shellac may induce some bleed-up. Why play around with a few feet? Bleach it, sand it, seal it with Claw-Lock or MagnaSand and get it out the door.
From contributor A:
The bleach will dissolve the dye like magic and if you don't like to sand you're in the wrong business. Why risk using different brands of products in a chemical cocktail when it is unnecessary?
