Tips to Prevent Tannin Bleed
If you've ever painted an older piece of furniture, trim, or cabinets white you may have run into an issue where the paint "yellowed" in a staining like pattern in certain areas. This my friends is called tannin bleeding and it doesn't just happen with white.
Tannin bleeding is not a malfunction of the paint, but occurs when a piece is not properly sealed or primed. With proper sealing and priming you can mitigate the appearance of the tannin bleed and even prevent it. Over the years us Brass Tacks ladies have witnessed and fixed our fair share of tannin bleed on the furniture pieces we refinish and we have a couple tricks up our sleeves to share with you.
Tip 1: After sanding and cleaning, seal your piece with 2 coats of Shellac.
No matter what color you are painting it's a good idea to create a barrier between the wood and the paint. We do this to almost every piece of furniture we paint. Not every piece will bleed, but when they do, we typically don't see it until after we apply the top coat. It's a lot easier to apply those to coats of shellac then it is to be almost finished and have to start all over again.
Tip 2: When painting with lighter colors (whites, pastels, light greys) we recommend using a stain blocking primer.
There are SEVERAL brands on the market. If we are sticking with water based products we are HUGE fans of General Finishes Stain Blocking Primer. Again, you apply 2 coats and you can brush or spray it. Even though we spray majority of our paint we tend to apply this by hand because it is on the pricey side and spraying tends to use more product then hand application. We've also had luck with Sherwin Williams Oil Based Primers, although we have used them as frequent as the General finishes.
Sometimes, even after following these steps we have still experienced tannin bleed after applying the top coat. It can be frustrating, but often if we add another coat of shellac on top of the primer, re-spray the paint, and re apply poly the second round is a good enough barrier to prevent any further bleed.