What is this about blocking tannins with a primer for tropical woods? You can see on my YouTube channel how I restore a garden table that has a top made of multiple pieces of tropical wood. This top seemed to be in very bad condition, but when sanding it, it turned out to be tropical wood that was almost in perfect condition despite being outside in the rain for years. It was an opportunity to do an interesting project and try a stain blocker for wood.
The garden table I am talking about belongs to a friend, and when he asked me to restore the metal base, he said the top was for throwing away. But when I saw the photos, I was skeptical and told him to bring the top as well.
As you can see in the image, it looks like these pieces of wood wouldn’t be good for much and would be irrecoverable. But as soon as you touch them, you can tell it’s good quality wood, probably tropical wood.
As soon as I started sanding it, I realized it was tropical wood. And I thought it was going to be a complicated task, but to my surprise, the paint came off too easily. So, I did a bit of research and discovered that these woods have a lot of tannins and can be sweating tannins for a long time.
Apply tannin blocker for wood
But, what are tannins? Tannins are a substance found in trees that help protect them. In the case of tropical woods, they have a lot of tannins. This is great because it helps these woods withstand the outdoors very well. But they have a couple of drawbacks: paints and varnishes adhere poorly to these woods that sweat so many tannins, as I could see when sanding; the tannins the wood sweats leave stains, called tannin stains on the wood, which spoil the appearance of the wood.
The solution is to apply a primer with a tannin blocker for wood that will prevent the wood from sweating tannins and will also help paints, varnishes, and other products adhere well.
The first step is to sand the wood well to remove the layers of paint. First with a sander with medium-grit sandpaper, then fine-grit sandpaper, and finally, I sanded everything by hand with very fine sandpaper.
The tannin blocking primer has a nice color that goes very well with tropical woods. The one I use is water-based and is very easy to apply with a brush. But the can warns us not to shake it too much, or it may start to foam. And yes, even if we load the brush a lot and move it quickly on the edges and corners, we will see that it foams immediately. When that happened, I simply squeezed the brush on the edge of the can and spread the primer on the wood well.
A little problem I had was that the day I painted it was very hot, and when we have to paint, it is best to avoid very hot days. The problem is that the primer started to dry immediately, and when I turned the pieces to paint the top side, an effect of double layer with a visible lower layer of paint remained on the edges underneath. To correct this, my trick is to moisten and insist a bit on those edges so that the primer gets wet again. Since that layer is not very dry, it mixes immediately, and the double-layer effect disappears.
The result after applying the tannin blocker is spectacular. And we thought the wood couldn’t be recovered.
Apply exterior wood protective stain
I let the primer dry well and applied an exterior wood protection.
On top of the stain blocker for wood, I used a water-based decorative protective transparent stain of the same brand. It is necessary to apply at least two coats of this stain and a maximum of three. I applied two.
It’s interesting that these transparent stains create a whitish layer when applied. But when they dry, they become perfectly transparent.
As I said, I apply a couple of coats of protective stain of the same brand, respecting the drying times. The only thing is that after each coat of stain, when it was already manageable but not yet completely dry, I lifted all the pieces to detach them from the wooden sticks I placed them on and let them finish drying for the time indicated on the can.
If you like how this tropical wood turned out once recovered, you can’t miss how good the garden table looked once restored. You can see it on my YouTube channel while I prepare an article.