Annie Sloan chalk paint – bleed through – beaten
Tannin, or resin from leaky knots will bleed through water-based paints that have no stain inhibiting ingredient. Annie Sloan chalk paint may therefore suffer from bleed through. That is just the way it is. But never fear.
The girls’ solution – from Annie Sloan’s site
With some pieces of furniture, typically pieces from the 1930s and 1940s, after painting the first coat there is either a yellow or pink stain which bleeds through the paint. No matter how may coats you paint, the stain colour will continue to bleed through.
The ANSWER is to get something called *Knotting or sometimes it is called shellac. Get the clear one and apply it using a pad rather than a brush. It dries in minutes and you can get on with painting immediately!
( *it’s a natural product from an insect in South East Asia, using a resin deposit that the insect extrudes to help them stick to trees. Strange but true!)
Clear shellac knotting
Yes, the lac beetle is a strange beast which isn’t oozing quite as much as it has in the past, leading to sky-rocketing prices for shellac based sealers. (This is a taste of what shellac is used for.)
Clear knotting or “white knotting” is bleached shellac, and is essential if spot sealing the occasional stain. ie It will dry a pale shade of honey and the subsequent dabs of chalk paint will cover fine. You can get International from B&Q type places, Ronseal do one.
Patent knotting is the dark brown shellac which you should avoid for dealing with bleed through on chalk paint, because it will take a lot of covering.
A boy decorator’s solution
Styptic knotting – is “white” knotting, but styptic sounds a bit more “craftsman-like” than plain knotting and is a professional decorating product as traditional and old as the hills!
And if you have lots of bleed through to heal, I wouldn’t dab, I would seal the whole surface with knotting!
After the first coat of chalk paint, this door panel stained in several big patches. So rather than be selective, I painted it all again with styptic knotting, and waited a couple of hours before over painting. What you see is one coat of chalk paint nearly finished.
Trust chalk paint ahead of knotting
I would definitely advise against over-thinking the bleed through situation – ie don’t take the normal painter approach of trying to seal knots or dodgy surfaces before you apply the first coat of chalk paint. Follow the Annie Sloan mantra of no prep, let the first coat of chalk paint find the weak spots, if any, and if required, then seal over the bleed through.
Couple of things about knotting.
Technically you should lightly abrade a coat of knotting before overpainting to provide a key, it is very shiny. But this is chalk paint, so who needs to rub down anything to make it stick!
One or two coats?
I was taught to apply two coats of knotting, the second one for added peace of mind. The second coat has to go on very quickly and no fussing, as knotting is a reversible coating. ie apply it over itself and the solvent in the topcoat softens up the coating beneath. This reversibility is a pain, but it has one advantage in that you can constantly revive brushes used in shellac paint, by dunking in shellac-based paint.
Do you need 2 coats of knotting in this situation?
I didn’t think it was necessary in this particular situation. But other times, you are best advised to coat twice for belt and braces.
Does knotting cure all bleed through
Yes, but no, but yes but…
Ordinarily, yes, but sometimes a weepy knot can bleed so badly that the resin will lift any coating, even shellac-based products.
Knots that are scuzzy, but have stopped exuding resin, you can wipe over with a rag soaked in meths to clean away old residue. Now I am going to contradict what I just said, but in this instance, if you have seen a knot that needs this much attention, it would be a good idea to seal it a couple of times with clear shellac knotting before chalk painting.
Very bad knots can be drilled out and filled.
What is Zinsser BIN?
Zinsser BIN is pigmented shellac, so you get knotting and white primer in one.
Is BIN suitable to stop bleed through?
Yes, but if you spot-prime bleeding patches with 2 coats of BIN using a brush, and overpaint with any colour other than white, you will probably see the white sealer through the chalk paint. I say probably, because it didn’t happen on one example I show elsewhere in the site, but I think that was down to the BIN being sprayed and the edges were nicely feathered. And I was lucky?
But basically, follow Annie Sloan’s advice with clear knotting. Apply with a pad on random bleed through, making sure to feather out the edges else it will ridge. And if staining is widespread, my advice is that it can often work out quicker and less stressful, with less thinking involved, to simply seal complete sections.
If you have any other questions, head over to the forum we have about chalk paint and furniture painting. A few of the other Traditional Painters I work with will have something to say, I am sure.
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