What kind of resin should I use?
Posted February 27, 2013 by Katherine Swift
What kind of resin should I use for making jewelry and other projects?
This is one of the most common questions I get asked about making things with resin. There is no ‘one size fits all’ resin, and there are MANY things to consider when choosing a resin. I will walk you through how I look at the process, whether I am doing resin for myself or helping another resin crafter make a decision.
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 resin caster, I cannot stress here enough that you need to start with an epoxy resin . Why? Relatively speaking, epoxy resin is the ‘easiest’ to work with. It generally doesn’t require a respirator mask and tends to be the most forgiving of environmental factors, such as humidity. It also usually mixes as 1:1 to 2:1 ratios, so it’s easier to get the proper measurements (versus drops into ounces). You will still need to take the proper resin safety precautions. but I generally don’t worry about using epoxy resin in my home like I do when using polyester or polyurethane resin. Epoxy resin is also generally widely available and usually has the fewest shipping restrictions (some can ship by air). I also like that epoxy resin 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, “Which kind of epoxy resin should I use?” Once again, it depends on what you want your final casting to look like. Here’s a few other things to consider when choosing a specific epoxy resin.
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 have a yellow tint to them, which varies depending on the kind of resin. If you’re unsure about how clear the resin is when cast, be sure to 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 (extra expense to remove the impurities). Know too that if you’re going to add color, having a color free clear resin probably isn’t as big a deal since the yellow tint will make a minimal impact to the final casting. You may even want to consider using an opaque resin, which will save you some money.
Mold or no mold?:
Are you trying to cast the resin into something, or are you wanting to put the resin on as ‘stand alone’? 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.
Of course each epoxy resin has its own specific advantages and disadvantages, so if you’re a beginner resin jewelry maker, I would suggest you experiment with different kinds of resin. You will eventually develop a preference based upon your experiences!
So if epoxy resin is so great, why would I use anything else?
Unfortunately, epoxy resin can’t do everything. Relatively speaking, epoxy is a ‘soft’ resin. You may have noticed that when you cast epoxy resin, you
can dent your fingernail in the finished casting if you try hard enough. Polyester and polyurethane resin both cure very hard. When you’re done, 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. (Epoxy resin won’t 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 resin to get it glossy!” Sit down, I have a few downsides to share with you. First polyester and some polyurethanes require that you wear a respirator mask with them. In fact, polyester resin will literally take your breath away the smell is so bad. I would NEVER do this 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 the resin then leave for the day.)
Polyester resin does 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 .) Oh, and one more thing about polyester resin, while it may be crystal clear on the day you cast it, it will yellow with time. This yellowing is also sped up by exposure to UV light. (Now that being said, I have experimented with polyester and put finished castings in the Florida sun for days to see what happens. Overall, I’ve been pleased so far — so I’m thinking this yellowing will happen in years, not months or days.)
Polyurethane resin, on the other hand, generally has fewer curing issues and there is a lot of options when choosing one, but you should know that polyurethane resin is VERY moisture sensitive. In fact, it hates humid weather. The only way I could get polyurethane resin to work for me in Florida (moderate to high humidity) was to completely seal off a room and run the dehumidifier constantly. While I loved the finished product and loved that some of these polyurethanes allow you to have a completely cured and demolded piece in 15 minutes (yes, I said minutes), it was just too difficult to make all of that work. (A 15 minute cure time meant I only had a 2 minute pot time, which meant it was nutty trying to mix and pour in under 120 seconds!) You can get polyurethanes with longer pot (and cure) times, but that meant, at least for me, a longer period of time to run the dehumidifier to make sure it cured properly. If you’re going to venture into polyurethanes, also know that since polyurethanes hate moisture, 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. If I lived in a less humid environment (like the desert), I would definitely do more with polyurethane resin as I suspect I could work with it without needing a dehumidifier.
So now that you know a little more about the resins you can use for making jewelry and other resin crafts, don’t forget to read our article on how to make resin jewelry . You can also find all of our jewelry quality resin in our resin category.
What else do you consider when choosing a resin for jewelry making or crafting?Source: www.resinobsession.com