Casting resin pen blanks is an absolute blast, whether they are pure resin or hybrid pen blanks that include various types of wood and resin together. I love making something real and beautiful out of what was, an hour before, two clear jugs sitting on my workspace. I want to cover some common topics when I get asked "How to cast resin pen blanks" in this article.
Casting ResinWhen it comes to casting resins, there is a variety available on the market. Some are used in the marine world for boats, others focus on being topcoats for countertops and bar tables, and others may be geared for heavy-duty use like the types of epoxies used to coat garage floors.
Whether you're making pen blanks, ring blanks, game calls, or other craft style applications, a few names come to mind. While not at all an all-inclusive list below, if you're just starting out, these are usually the 3 names you'll likely come across in the various Facebook groups.
- Royal Palm
- Liquid Diamond
Before diving into the virtues of each, it is probably important to talk about the different types of resins out there so you know what's available and what will best suit your needs. Epoxy resins, polyurethane, and polyester resins are what you will likely run across on various websites selling these products.
Epoxy resins tend to cure clear and usually, they will not turn cloudy if there is moisture in your mold or in the room you are casting. The long open time gives you plenty of time to mix in colors, pigments, and dyes, and usually, Epoxy resins will stick to pretty much anything. For that reason, a lot of hybrid pen blanks, those that are a combination of wood (or other additives) and resin, tend to be made with epoxy resins. These resins will often take longer to cure, sometimes days, and they can be one of the more expensive resins to use, but if done right and the directions are followed, you'll end up with some really nice blanks. Note, these resins don't do well in cold weather so if you're trying to cast in your outdoor shop or garage in Wisconsin in January, you're probably going to want to bring stuff inside.
First, you need to know that polyurethane resins flat out don't like moisture at all and it'll react to CA (gases are given off by the glue, even if you let the glue counter cure for days), as well as being really touchy when it comes to your measuring of the parts. Usually mixed by weight, it is a good idea to have a Grams scale that can go to the .01 reading. If your mixture is off by a little, it is not a huge deal, provided you're mixing a big batch, but the smaller your batch, the more an "off" mixture can harm the outcome. You'll end up with pen blanks that don't cure at all and then you're stuck with the difficult task of trying to get incredibly sticky uncured resin out of your molds. Having done this several times myself, it is a lesson better learned by reading a blog post like this than having to go through it yourself. But if directions are followed and your measurements are perfect, polyurethane resins work well with mica powders or liquid dyes and they have a pretty quick working time, so getting good color separation isn't difficult. You'll likely need a pressure pot, though, as the short work time means that there is not a lot of time for air bubbles to naturally float to the top before curing.
Polyester resins stink, literally. I don't like using these because of the odor and the fact that the stuff is considered toxic. Even with good ventilation, or casting in a shop or garage, you're going to notice the irritating smell. It also is touchy when it comes to the moisture in the air and the temperature of your casting area. It doesn't like humidity and you'll have issues if it is too cold or too hot. With that said, you can weigh the positives against it as being relatively inexpensive, you don't need to cast under pressure, and you can usually get this type of resin at hobby stores such as Michael's or Hobby Lobby so you won't need to make a special order online and pay heavy shipping costs. It casts clear so it is a decent resin to use if you are trying to label cast a blank. You'll likely need to do a test if you plan to color the resin, though, because the chemical make-up of it can alter the dyes and pigment powders you try to use so a small test in a tiny cup using your coloring agent is always a good idea before trying to cast a big block.
So with the types of resins now covered, let's talk about a few specific products you will likely see being used.
Liquid Diamond casting resin
"Liquid Diamonds casting resin is specifically designed for seamless castings and super clear coatings. This resin cures clear, shiny, & bubble-free. Excellent for castings, jewelry making, artwork, and fine coatings. This product is easy to work with and safe to use indoors. VOC free and virtually no smell."
I've enjoyed using Liquid Diamond casting resin, an epoxy, on many pen blanks. What I like about it is that it is very thin and because of this, any air bubbles that form when you are stirring the resin parts or adding various coloring agents, like pigment powders or dyes, will inevitably "shake themselves out" before the resin cures. For this reason, many pen blank makers will use Liquid Diamond because you don't necessarily "need" a pressure pot to use it. But a consideration that must be taken into account is that because of the long work time and long cure time if you are trying to pour blanks with multiple colors and are looking for very good color separation, instead of the colors bleeding together, it's more difficult to achieve this with Liquid Diamond casting resin. Buy Liquid Diamonds
Royal Palm casting resin
"Royal Palm Resin is an epoxy resin. It comes in 2 types a thin and an original formula. The thin formula is very fluid (a bit thicker than water) and the original is a more viscous type (more like thick syrup or honey)."
Similar to Liquid Diamond, Royal Palm resin is also very thin and easy to work with. They do have a thicker version as well, but you'll be able to achieve the same results using either.
Alumilite casting resin
This is usually my go-to and there are several versions to choose from, depending on what you're looking to do. Most casters will use "Clear Slow" or "Clear", while others will opt for the "Amazing Clear".
This is a great resin to use if you're looking to get good color separation. The work time is pretty low, only a few minutes, so after your resin is thoroughly mixed, you can add the colors and then begin your multi-color pour relatively quickly. Once poured, you'll want to put your casts into a pressure pot to eliminate the bubbles. You can usually pop your molds out of the pot after an hour or two and they'll be hard and beautiful, though full cure takes longer (read the directions!). Buy Alumilite Clear
Alumilite Clear Slow
Also a great resin for color separation, the clear slow version has a longer work time, but only by about 10 minutes. So if you're a bit on the slower side of things, or you're casting a few large batches of pen blanks, this version gives you more time to get your pours done and the molds into your pressure pot before it starts to cure. Like Clear, you can usually take the Clear Slow molds out of the pressure pot after a few hours. Remember to read the directions to get the full cure time before you go turning any, though. Buy Clear Slow
Alumilite Amazing Clear
This stuff is a bit different than the other two versions, which are very thin, almost like water. Amazing Clear is thicker and heavier and has a much longer work time, 30-40 minutes. Because of this, color separation is a bit more difficult because in order to get to the temperature that is needed for the resin to start to cure, the resin becomes gummy and thick. So it doesn't pour great and you'll end up trying to pour it before it becomes gummy, and that causes the colors to bleed together more than you'd get with the above two options. This stuff still works very well, though, and if you're doing a single color pour or you purposefully want your colors to bleed and blend together, this cheaper alternative to "Clear" or "Clear Slow" can do the trick. Buy Amazing Clear
There is a lot more to cover when it comes to resins but this should be enough to get you started on learning the difference between resin types and understanding the role that each brand can play in the pen blank making world.