1

I've just started making epoxy resin jewellery as a hobby, but I'm having trouble getting it to not be sticky.

I've used the AB resin 1:1 instead of 2:1 and that takes ages to set and is still sticky. I've now gotten a UV resin and with light it's getting hard but still sticky.

Where am I going wrong?

Improve this question
2
  • 1
    Epoxy does not dry, it cures ( polymerizes) if it has the correct mixture.
    – blacksmith37
    Jan 27 at 15:12
  • 2
    When you say that you're using 1:1 instead of 2:1, do you mean that you're using a specific type of resin that uses a One-to-One Ratio rather than a Two-to-One ratio (Wisebond Deep Pour, for example). Or that you're mixing a Two-to-One resin with a One-to-One ratio for a specific reason (EG, you're doing something different from that which is suggested by the manufacturer)?
    – Aaargh Zombies
    Jan 28 at 19:28

2 Answers 2

Reset to default
6

2-part epoxy must always be mixed in the correct ratio.

The chemical components of 2-part epoxy are designed to bond with each other. Each unbound component is liquid, but as soon as they bond, they become solid. Intentionally using a different mixing ratio results in unbound (liquid) components left in the final object, so part of it is still liquid. You always get the best results with 2-part epoxy if you mix it as precisely as possible according to manufacturer guidelines. Please keep in mind that some ratios are given in weight and some in volume.

UV resin is also a mix of chemicals that is initially liquid, but the components only react with each other if exposed to UV light. Depending on the chemicals used (for example this is very common in UV nail gels), this reaction does produce some by-product that forms a sticky, almost oily film on top of the resin. If you pour a very thick layer of UV resin, this by-product cannot escape to the surface and is trapped in the resin instead. For UV nail gels it's recommended to wipe the cured resin with nail polish remover after it's cured.

As Chris H mentioned in the comments, UV resin also requires a certain amount of light to cure. Shining a small UV flashlight on it may not be enough to cure the resin properly, even if you shine it for longer. Also keep in mind that opaque or colored UV resins need a lot more light and longer to cure because the color blocks the UV light from reaching deeper layers.

Improve this answer
2
  • 2
    (Industrial) UV resins I've used in the past have had an additional failure mode leading to stickiness: time doesn't necessarily make up for low UV intensity if you don't achieve the minimum illumination
    – Chris H
    Jan 26 at 17:43
  • 2
    With UV resin, it's critical to work in thin layers as it's hard for the UV to penetrate. It's extra steps, but don't worry about "layer lines"; it all melds together with no visible signs of layers.
    – fixer1234 ♦
    Jan 26 at 19:23
3

Presuming that you've mixed the resin to the correct ratio, mixed the two parts together sufficiently, and allowed the correct amount of time for them to set, it's possible that your resin is too cold. This can slow down the curing process, causing it to be sticky long after it should have fully cured.

If this is the case, place them somewhere warm and allow them additional time to cure. Overnight next to a radiator, for example. But not too close in case they warp.

If this isn't the case, you should look at any additives that you are using to color the resin.

For example, if you are using alcohol based inks that aren't properly mixed in with the resin, are allowed to sit on the surface of the resin, or if you use too much alcohol based ink and have changed the composition of the resin.

As you're experiencing the same problem with both UV and two part epoxy resin I would suggest the latter of these two may be the case.

Improve this answer
3
  • 2
    The question states that they're using a ratio different than specified for the epoxy. That alone explains the epoxy cure problem. With UV resin, the almost universal issue is too thick a layer or inadequate curing. Also, they're using it for jewelry, with no indication it is anything but plain resin, the most common mode of use. If you think it's possible that for both types of resin, the issue is a colorant not mentioned in the question, it might be worth asking for clarification in a comment on the question. There's an expression, "When you hear hoofbeats, think horses, not zebras." :-)
    – fixer1234 ♦
    Jan 27 at 21:43
  • @fixer1234, While the OP hasn't explicitly mentioned the use of colorants, this could be a possible explanation for why they are having an identical problem with both one part and two part resin as alcohol inks can have this effect on both. If you believe that pour volume or thickness may be the answer then it might be the basis for an answer of your own.
    – Aaargh Zombies
    Jan 28 at 12:01
  • 1
    @fixer1234, I read the question as meaning that they were using a 1:1 ration resin, rather than a 2:1 ratio resin. Not that they were mixing a 2:1 resin at 1:1. (Widsebond deep pour uses a 2:1 ratio, so it is a thing). I've added a comment asking for clarification.
    – Aaargh Zombies
    Jan 28 at 19:32

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .