Originally published March 2013. Updated May 2020.
If you are asking yourself ‘What kind of resin should I use?’, you have come to the right place.
This is one of the most common questions I get asked about art, jewelry and crafts. There is no ‘one size fits all’ resin, and there are MANY things to consider. I will walk you through how I look at the process, whether I am creating for myself or helping another artist choose a resin.
Let’s imagine you have walked into your favorite butcher shop. You tell the meat cutter at the counter that you want a steak and ask what kind you should buy. One of the responses you’re likely to get is a question asking “What do you want to make?”. Choosing a resin is really no different than this situation. To be more specific, I would frame my response into “What are you hoping the end result to be?”
If you’re a beginner, I cannot stress here enough that you need to start with an epoxy resin. Why? Relatively speaking, epoxy is the ‘easiest’ to work with. It generally doesn’t require wearing a respirator mask and tends to be the most forgiving of environmental factors, such as humidity. Epoxy resin also has the longest shelf life. I also like that it generally has the longest pot time (approximately 20 to 40 minutes to work with it), so it’s great for beginners that are still fumbling and getting used to working with resin.
So you may be asking yourself, “What kind of epoxy resin should I use?” Once again, it depends on what you want your final casting to look like. Here are a few other things to consider when choosing a specific epoxy.
If you want your final project to be clear, you want to make sure to start with a clear resin. Also realize that clear doesn’t necessarily mean ‘color free’. Some clear resins will cure with a yellow tint, depending on the brand. If you’re unsure about how clear the resin is when cast, check with the retailer or manufacturer before making a purchase. Know that the clearer and more color free the resin, the more it will cost.
Fill a space or coat a surface?
Are you trying to cast the resin into something, or are you wanting to put it on as a coating? If you want to place the resin on something without sides, you want to be sure you are using a doming resin. This kind of resin is a bit thicker and has the extra surface tension to make sure it doesn’t run over the sides. Know too though, that this resin being a bit thicker, is also more difficult to remove bubbles from. If you want to fill a mold or space with sides, you want to use a casting resin.
Of course, each has its own specific advantages and disadvantages, so if you’re a beginner, read this article about the differences between these two types.
So if epoxy is so great, why would I use anything else?
Unfortunately, epoxy resin can’t do everything. Relatively speaking, it can cure soft. You may have noticed that when you cast epoxy, you can sometimes dent your fingernail in the finished casting if you try hard enough. Polyester and polyurethane resins both cure very hard. When fully cured, they can have the hardness and clearness of glass. In fact, both can be polished to a high gloss with a polishing wheel and the appropriate compound. Many epoxies cannot withstand the heat produced by a polishing wheel and will turn cloudy on the surface.
I know what you’re thinking, “Oh my gosh, this is exactly what I need! I hate having to do all that extra stuff to epoxy to get it glossy!” Sit down, I have a few downsides to share with you. First polyester and some polyurethanes may require that you wear a respirator mask with them. In my opinion, polyester resin will literally take your breath away the smell is so bad. I would NEVER cast this resin in my house or a space that I needed to occupy in the next 12 hours. When I do resin polyester in my studio, I save it for the last thing in the day. I cast, then leave for the day or I will even cast it outside, weather permitting.
Polyesters do have an advantage over epoxy in that is it generally cheaper and is great for casting deep molds. However, polyester resin has a short pot time (generally 8 to 10 minutes) and the surface exposed to air during the curing will remain tacky. You can either sand this side down or coat with resin gloss sealer spray once cured. If you think you might want to cast polyester resin, here are five things you should know about using polyester resin.
Polyurethanes, on the other hand, generally have fewer curing issues and there is a lot of options when choosing one, but you should know that they are VERY moisture sensitive. If you’re going to venture into casting polyurethanes, you need to make sure to use colorants specifically designed for them.
So here’s my breakdown of how I use resin:
I use epoxy for everything unless I am trying to cast something larger that I want to have a shiny gloss finish. In that case, I use polyester because I can polish it on my buffing wheel instead of using the gloss sealer spray or coating with another layer of resin. I like polyurethanes when I need a casting quickly that doesn’t need to be clear or transparent.
Want more help? Read our RESIN BUYING GUIDE for a complete breakdown explaining what kind of resin should i use.
Unpublished Blog Posts of Resin Obsession, LLC © 2020 Resin Obsession, LLC