What is Blotch?
If you stain your projects, it’s likely you’ve confronted a phenomenon known as blotch. This is when the stain absorbs unevenly resulting in a seemingly random arrangement of light and dark areas. In the examples below, you’ll see a pine board with nothing but dark stain on the left. The board on the right was first treated with my blotch prevention recipe. The untreated board is what we’d call “blotchy” as it has lots of contrasting light and dark areas. The treated board has much more consistent color with far fewer dark blotches. Pine is particularly bad when it comes to blotch and if you like the “rustic” look, then you might not need to worry about taking measures to prevent blotch. But for those who prefer a more even stain appearance, you might consider trying my DIY blotch prevention formula.
The formula I like to use is actually a combination of two classic blotch remedies: glue size and diluted finish. I consider this recipe a starting point that you can use to develop your own formula for the stain and wood species you’re working with.
After mixing well, apply to the surface liberally and let it soak in and dry. Once completely dry, sand lightly with 220 grit to knock down any roughness. Proceed with the staining process. Since the mixture is glue, finish and water, it can keep for a very long time. Dump it into an empty quart can and throw it on the shelf until the next time you need it. Be sure to mix well before use.
After testing the formula on a piece of scrap, there are two possible outcomes that may require adjustment.
- Too much blotch? Add a little more glue to your mixture and try again.
- Blotch is gone but the color isn’t intense enough? Dilute the mixture with water and try again.
Ultimately, this process entails a decent amount of trial and error and keep in mind that with some woods and some stains, you’re just not going to achieve perfection. At some point we need to let wood be wood, flaws and all.
Remember there are lots of methods and products on the market to reduce blotch and in some cases you might find they perform better than this DIY formula. But in my experience, this stuff works as well if not better than anything else and I can make it as-needed out of things I already have in my shop.