Epoxy Resins have been used in woodworking for a few years and are becoming more and more popular because of the increasing number of ideas and situations that they can be used in to enhance our woodworking projects. In some cases they are used to make new and interesting projects, in others they are used to extend the strength or volume of wood by making projects larger by incorporating resins in them.
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Working with 2 part epoxy resins is not an inexpensive alternative in woodworking but more like an investment in creativity. Epoxy resins are not inexpensive to purchase so if you are using them you will want to make sure you use them wisely and effectively, and that is really the purpose of this article and video ... to give those who are interested in experimenting with resins a better idea how the work and what to expect ...
Like anything else we do in woodworking the first thing we need is a plan or idea on how we are going to use the resin and there are a number to choose from, all of which give similar end results but vary in how they are mixed, what they give off in fumes or odors, how much they heat up during curing, which can affect how big or how thick a pour can be made, and what they will accept for colorants.
Epoxy Resins most often cure and harden to a clear product and adhere to wood amazingly well, which makes them very well suited as a woodworking partner product. They always come in 2 separate containers, the Resin, and the Hardner, and these are mixed together just prior to use. I have been using a Canadian product called Ecopoxy because the company has worked hard to make a product that is as ecologically friendly as it can be, and what I like most is the low odor or working with this product, but there are many others to choose from in the marketplace as well.
When selecting a product, you will want to know what the mixture ratios are, some are mixed one to one (1:1) others two to one (2:1), etc. In most the larger volume of material will be the "Resin" while the smaller quantity would be the "Hardner".
It is very important to know what the mixture ratios are for the product you are using because varying from what the manufacturers recommendations can mean you end up with a product that hardens too quickly and perhaps heats up too quickly, which can cause a variety of issues, and if you skimp on the hardner you can end up with a product that doesn't cure for days or weeks, or maybe never ... so you need to follow the manufacturers recommendations in order to achieve success.
Because epoxy resins are not inexpensive, you will want to make sure you mix the correct amount and not waste any material, but remember ... you WILL need to mix more than you need by at least 15% and possibly more depending on your project. One of the main reasons you will want to mix more is because you NEVER want to have to scrape the side of your mixing container to get the last bit of mixed resin. Whether you mix your products by hand or machine, you will NEVER mix every portion of the material, there will be some material on the inside or your mixing container that will never get mixed and if you scrape this material into your pour, you will most often end up with all or parts of your finished product that will remain "sticky" ... for days, weeks and sometimes forever ... so NEVER scrape the inside of your mixing container to get the last drop from it. Pour it out, fill your mold and don't worry about the last little bit.
The question of how much total volume of resin you will need to mix for your project will help you economize the use of the product. You can figure out what you need 2 ways, you can do the math if you like width x length x height if it is a straight even pour, or if it is variable, you could use some other product that takes up the volume that you can transfer into a measuring container and figure out the mixture from that. For small pours died beans or beans work great, they inexpensive and work well, for a bit larger pours you could try something like marbles or anything else medium in size and for much larger pour Styrofoam packing chips work great,
One of the great things about working with resins is that you can add many things to them like colorants, or you can leave the resin to cure clear. If you decide to add color you will want to know ahead of time whether you will want a translucent color, that is a color that allows light to come through like a stained glass window pane, or do if light will not pass through such as in the lid for box, you will want to use an opaque color that gets its color from light reflecting off of it, exactly like paint does.
No matter what color you choose to start small, especially if it is going to be translucent color, for this you only want a hint of color otherwise the color can take over and take your translucent effect to an opaque effect because too much colorant was added.
It's good to keep in mind that anything you do with a resin, you are basically going to be making a mold to pour the resin into, in some case you will be adding wood into the mold as well, but in the end, it is still a mold and it needs to be watertight. A mold that is not watertight may allow your mixed resin to flow out or your mold ... on to your workbench and eventually on to the floor of your workshop. This is actually a more common event than you might think ... I have heard of many pours the ended up on workshop floors ... which is not fun clean-up, not to mention the cost of materials wasted.
There are a few things to remember about pouring the resins ... first, because it's a liquid, it WILL find it own leveling. This means that if your mold is not level your resin will lever its self within the mold and when you pull out your project one end of the resin will be thicker than the other. Make sure the base of your mold is sitting on a level surface.
Remember that wood floats so if you are adding pieces of wood, they need to be clamped down to the base of your mold by whatever means works for you. Some people use clamps, others attach wooden cross members to the tops of their molds then use these a braces along with blocks of wood underneath to hold the wood down and stop it from floating on the resin.
Molds can be made from a variety of items. I try to clear plastic sheeting or thick trash bag material as the base of my molds but other use Tuck tape and firmly stick it to their molds, then use a tube of silicon to seal all the corners so the resin will not leak out. Either of these works fine but I have seen people who have had to literally destroy their molds in order to get their finished products out because the resin has adhered to the Tuck tape and silicone so firmly.
Once you have done all your prep work, the next thing to do is mix your resin according to manufacturer specs. In almost every case there will be a varying amount of tiny bubbles that will show up in your pour. Some products tell you to let the product stand for 5 minutes or so after mixing to help allow some of those tiny bubbles to come to the surface and dissipate, but most of the time there will still be bubbles trapped in your pour. If your pour is translucent or clear it is more critical to get these bubble out and one of the best ways of doing this it applies a small amount of heat to your poured product to help allow the bubbles to surface where they pop and leave the clear liquid. What you use to heat your poured resin can be important because some resins can be flammable so always the best to use is a heat gun on moderate heat and slowly go over your pour, heating it up and allowing the bubbles to rise and pop.
Most epoxy resins will cure within 24 hours, but larger or deeper pours may take longer. Deeper pours can be a concern in terms of heat build up as the pour cures. Heat build up in resin cures can cause a variety of mishaps and if you have a large, deep pour you may want to set up a fan to help cool down the pour as it cures to help prevent any flaws that may occur. Once again, if you have had a large and or deep pour it is always best to check with the manufacturer or the seller for any advice they may have on these.
If you have to, especially for bigger pours, it's a good idea to write down what you will be doing ahead of time at least in point form, just so don't forget a critical part. Better this than wasting wood and resin in a pour that fails for want of a simple step that was omitted.
In the end ... some remarkable and innovative ideas can really augment your woodworking projects, and often it doesn't take a TON of epoxy to do this, sometimes just adding a bit of color or a unique build can set your woodworking apart and it's fun to experiment with new ideas and materials. It may not be something you use on a regular basis but it's nice to know there is another tool in your woodworking bag that you can use when needed ...
Copyright Colin Knecht