Why does the bottle say 190F for 10 min? I’ve never cured a blank in 10 minutes, it always takes hours…
What this actually means…
This is how much heat energy is required to reach the gel phase of polymerization for the resin alone. This assumes an even heat transfer and an uncontaminated sample of the resin. This is done using a water bath or heat sync and test tubes when we are verifying the preset activation levels of the resin.
Why it does not mean you can cure a block of wood in 10 min at 190…
I remember watching my grandmother cooking with some very old pans when I was little. These pans had wooden grips on them so they could be grasped, even after sitting on a hot stove for a long time, and not burn your hands. Even today you will find wooden grips on cookware, grills, BBQ tools and more. Wood is a very good natural insulator and does not pass heat as quickly as many other materials. A metal spoon left in a pot to stir noodles will become very hot to the touch in a short amount of time, but a wooden spoon could be left in the pot the entire time and never get hot enough to burn your hand. For the resin in the very center of the block, enough time will be required to pass enough heat energy for the resin in the center of the block to cure. If your oven is set to an exact 190F, this will take even longer to achieve. It is also dependent on the size/thickness of the block, the species of wood and the condition the wood was in before stabilizing. Use of higher temperatures does increase risks. Damage to the wood or shop fires can occur if the temperature is set too high or the wood is placed too close to a heating element. Although considered a non-flammable substance, this does not mean the resin is not combustible. Wood is also a combustible material. This provides two fuel sources, wood and plastic for a potential fire. I commonly use an oven temperature of around 220F. In some cases I might use a little more heat, but do not recommend or use more than about 250F when curing in a convection oven (such as a toaster oven, kitchen oven (if you’ve got one dedicated for your shop), or electric smoker.
What other ways can I cure the resin? Are there any safer ways?
There are many ways! I’ve used quite a few of them actually. Some work better than others and there are some Pros/Cons to these other methods. I’ll list a few here and elaborate more on each in additional posts. Once I complete those, I’ll come back and link them below.
- Infrared (IR) cure
- Pressure Cooker
What can affect the cure?
Lots of things actually… many stabilizers use dyes to get bold colors and artistic blanks. Alumilite dye can affect the activation level of the resin. Using too much can cause the resin to gel up or turn to jelly… possibly even set up in your chamber. A ratio of approximately 1oz of dye per gallon of resin will give you a good color and is a safe amount. Using a massive amount of dye won’t always give better results. After a certain point, it is just wasting money.
Aniline dye can cause the activation to decrease. This type of dye can not really be over mixed. It will dissolve as much as it can and the rest will remain at the bottom of your mixing jug (along with some binder and other components which do not dissolve in the resin). While this can make the resin activation retard, bumping up the heat and extending the cure times is usually enough. If you do a lot of work with aniline dyes and activation level becomes an issue, get in touch with us and we can help you with this.
The wood itself can also affect the cure. Oily woods, lots of sap within the wood (even when completely dry to 0%MC, sap remains), tannin and free radicals that occur naturally in wood can all affect the resin. These are all things to consider when stabilizing. Any piece of wood CAN be stabilized, but that doesn’t always mean it should be or needs to be. For the woods that are very dense or contain higher levels of these contaminates require the process be adapted to work with the difficulties.
Remember, stabilizing resin is just another tool in your shop.
Just like any tool, adhesive or finishing product, proper use and preparation will give the best results. If you do not take the time to learn to use the tools and products in your shop properly, you will never get perfect results and may find it difficult to enjoy. There is not a single thing in your shop that will work perfectly with every piece or project. For instance, if you’ve ever used a thickness planer when working with wood, you’re aware of issues with interlocked grain, tear out and snipe. To get the best results with a thickness planer, you have to learn how the grain direction and type of grain is affected, the direction to feed the wood in, the aggressiveness of each cut etc. There are many pieces that can not be planed without some issues and will require a lot of sanding or other work to correct the issues. Stabilizing is not much different. The challenges presented by each species will be different and must be understood and worked with or around in order to achieve success.