How to Flatten Veneer
When I first started using veneer I was blown away with the selection of available species and burls that I could now use in my projects. They allowed me to use rare and exotic woods that I couldn't afford, and even if I wanted to spend the extra money, I didn't have a local resource to buy any.
When you start to use veneers like burls, you will notice that they are wavy and not very flat. Before you can use the veneer, you're going to need to flatten them. There are several different ways to flatten veneer but I'm going to cover how to use a product called Super-Soft 2 from veneersupplies.com. It's a great product that doesn't affect the veneer in any way, so you can stain and finish the veneer without any problems. Let's take a look at how I use it.
Spray the super-soft 2 softener on both sides of the veneer. Make sure the veneer is covered with softener. If you have larger pieces of veneer, or you'd rather not spray, you can dip the veneer in the softener as well.
Now that the veneer has softener applied, let it sit for about 15 minutes to fully absorb the softener. After the 15 minutes are up, I like to take a paper towel and dab away any standing softener. This just makes sure you're not going to have puddles of softener on the veneer when you put it in the press.
Place the veneer in a press (vacuum press or a shop made press) between two sheets of either brown paper or paper towels and either apply clamps to your press or sit some weights on top of the press to keep the veneer flat. After 6 hours in the press, replace the paper towels with fresh paper towels and let it sit overnight.
After 24 hours in the press you have a choice to make. You can stop here and switch to using a household iron to finish the drying or you can leave it in the press for 2-3 days to full dry, replacing the paper towels every 12 hours. If you opt to use an iron, you are applying heat to the veneer so splitting and cracking is a possibility. If you need to work with the veneer and can't wait the full 2-3 days, this is a good option. In my guild build I ironed the veneers after 24 hours without any issues. Just make sure to set your iron to medium heat and place a dry cotton rag over the veneer while ironing.
If you can't wait 24 hours, you have another option. You can spray the softener on the veneer, wait 15 minutes and then go straight to the iron to dry the veneer. This will work but comes with it's own set of limitations. It's mentioned by the manufacturer that the veneer may not stay as flat as long as if you were to let it sit in the press for 2-3 days to dry naturally. Any time you use an iron with Super-Soft, it is recommended to have plenty of ventilation as you don't want to breathe any of the fumes in.
If you want to watch the process above, check out the video below. It's part 3 of the veneered box guild build.