Blotch Control to Rule Them All
Article - February 28, 2011
One of the most common battles between man and wood involves blotching. How many times have you applied a stain to your latest masterpiece, only to be greeted with a blotchy splotchy mess? If you haven’t had the pleasure of experiencing blotch, its a phenomenon that occurs when a board takes stain unevenly, creating unsightly dark patches (a relatively “mild” case pictured left). Blotching can be avoided by various means, including sanding to higher grits, applying commercially available pre-stain conditioners, or pre-sealing with dewaxed shellac. The latter has been my personal favorite for years and you can learn more about it by watching (Episode 73 – Coloring Blotchy Woods). But as you’ll soon see, there’s a new favorite in the Wood Whisperer’s workshop.
What’s Wrong With Existing Solutions?
The typical methods we use to prevent blotch are certainly effective in that regard. But unfortunately, preventing blotch also means preventing overall color absorption. So the end result is a blotch-free board that is much lighter in color than you originally intended. Even using my old friend shellac, I always have to experiment to find a balance between the concentration of shellac, the number of coats, the amount of sanding, the color of the stain, and the number of coats of stain. The process is nearly always complicated and tedious and the results are typically less than ideal.
Enter Charles Neil’s Pre-Color Conditioner
Last year, Charles Neil came out with a new product called Charles Neil’s Pre-Color Conditioner. To be completely honest, I initially assumed it was just another version of the stuff we already have on the market. Believing 100% in his product and being a man of his word, Charles sent me a can to test for myself. Since then, I have placed two more orders and I haven’t touched my shellac in months! The product is THAT good!
What is it?
Although the product is new, the concept behind it is not. Essentially, this water-based non-toxic formula is a riff on old-fashioned glue size. Glue size is made by mixing good old PVA glue with lots of water and is used for all kinds of sealing applications in solid wood and sheetgoods. But Charles, with over 40 years of finishing experience, has perfected his formula so that its performance is both predictable and repeatable in pretty much any species of wood.
Let’s Put it to the Test!
One of the blotchiest woods I know is pine, so I divided a large square of box store pine into two halves. The left side was pre-treated with 1lb cut shellac (one coat on the bottom and two coats on the top). The right side was pre-treated with the Charles Neal (CN) formula (one coat on the bottom and two coats on the top). All four sections were then treated with a deep red gel stain. The first thing you’ll notice is how much darker the CN side is. Not only is it preventing blotching, its doing so while also allowing the stain to penetrate the wood fibers. Despite the appearance in the photo, I noticed very little difference between the single and double coats of CN Pre Color Conditioner. On the shellac side, you can see that it takes two coats to completely prevent blotching. But do you notice what else we prevented? Yup! Absorption of the stain! Hardly any of the color was accepted by the wood fibers. Many would say, “that’s because you used a shellac solution that was too concentrated!”, and they would be correct. But if I reduce the concentration of shellac, I will not only get more stain absorption, but also more blotching to go with it. This is the back and forth game you play when trying to balance shellac, stain color, and blotch.
No Stain = No Blotch, Right? Nope!
Now truthfully, I rarely use stain on my projects. I much prefer letting the wood age to its natural color, whatever that may be. But even then, blotch-prone woods can still be a problem. Oil finishes, for instance, bring enough amber color to the party that they too can blotch! Check out this piece of cherry ply from my recent wall-hanging cabinet build. After a single coat of oil, the dark areas are plain as day. But with a pre-coat of CN’s formula, the blotching is prevented without taking away the “life” of this beautiful cherry veneer.
Charles provided me with an initial can of free product for testing but I have purchased my own since then. I am also an affiliate for Charles Neil’s store so any purchase you make using these links helps support our efforts here at TheWoodWhisperer.com.