What’s Your Best Chance to Fix Resin Cracking?

why is my resin crackingYou just made something gorgeous with resin. Like you’re already dreaming about showing it off. Or selling it in your Etsy store. Or maybe, this one is good enough to keep for yourself. Then, you check on it later and immediately start screaming. Your resin now looks like a windshield your ex hit with a baseball batWhat’s going on? Your resin is cracking.

Why does resin cracking happen?

Cracking happens when resin gets too hot and cools off quickly.

Why does resin get hot?

Two-part resins include a part A (resin) and part B (hardener). When you combine the liquids, the resin mixture heats up and hardens into a solid mass. While a little bit of heat is necessary, too much heat can cause resin cracking.

How do you fix resin cracking?

Step 1:  Wait for the resin to cure and completely cool.

Step 2:  Sand the resin down to the level of the crack.

Step 3:  Coat it with a tabletop coating resin or polish the resin.

You can also cut out the area of the damage and refill it with resin, but you will see a seam line.

What if you don’t fix the resin cracks?

If there is only a crack or two, and you don’t mind the look, you can leave the resin cracking as is. Most people won’t notice.

If there are many cracks, or if you’re worried the piece’s structural integrity is compromised, then scrap your resin project and start over. You don’t want anyone to use what you’ve made with resin, only to have the piece fail later.

How can you prevent resin cracking?

Controlling resin cracking means controlling the heat of the resin reaction. To do that, there are three things you need to pay attention to:

1.  Don’t mix too much resin and hardener at once.

Resin kits have a maximum mixing amount. This is the maximum amount of resin and hardener you should mix together in one cup at a time. Mix more than this, and the resin will overheat and crack.

⭐️ BONUS: Get the maximum mixing amount for the resins sold in the Resin Obsession store in our resin buying guide.

2.  Don’t pour too thick.

The thicker you pour resin layers, the more heat builds in the resin mass. If you need to pour in thick layers, use a resin designed for that purpose. The Resin Obsession deep pour epoxy resin cures slowly, allowing heat to build gradually. You can pour it up to two inches thick at once. That makes it ideal for epoxy river tables and memorial flower paperweights.

3.  Cool the resin.

While it seems a little odd to say this, cooling resin may be necessary during the curing phase. You can do this by elevating the mold surface and allowing cool air to circulate underneath. You can also lower your room temperature.

⭐️ BONUS: Get more helpful hints in this article about making an epoxy table.

You should always prepare for epoxy resin cracking.

Worst case scenario–your resin may get hot enough to smoke or catch your container on fire.

I know because I’ve done it. You can see what happened when my epoxy resin overheated and cracked.

Hate making resin mistakes?

Me too. It’s why I wrote the ebook, Resin Fundamentals. I’ve condensed my 16 years of experience into what beginners need to know to be successful starting on day one. Buy the PDF book now for less than the price of a resin kit and get a download link in your email inbox in minutes.

Unpublished Blog Posts of Resin Obsession, LLC © 2023 Resin Obsession, LLC

Like this post? You may be interested in  How To Use Epoxy: 10 Dumb Mistakes To Avoid

15 thoughts on “What’s Your Best Chance to Fix Resin Cracking?

  1. I’ve been doing large or 4×6 photos cubes and my constant battle is bubbles micro now after being advised to pour in small amounts. I also notice the lines between pours that are driving me nuts. I’m more concerns with the micro bubbles. I’ve research and what I’m finding is something about a pressurized process which seems to be a bit much. please help.

  2. Hi I have been making tumblers and I bought the amazing brand resin epoxy. I tried the 2 small bottle and the epoxycame out nice and shinny. I purchased the half gallon jugs the epoxy dries with fine cracks all through the epoxy like shattered glass. We cant get it to stop doin it no matter what we try. Any help would be helpful. Thank you

  3. Your article on applying resin to glass was very informative! I understand now that the properties in resin and glass are different and react differently to heat and cold. I will be applying a thin layer of resin to my glass project, so I don’t expect this to be a problem. Your resin for art sounds like the perfect product for me, and I will place an order when you get your supply of translucent color tints back in stock. I am going to order your beginners ebook on everything you need to know about resin. Your web site has been most helpful and educational! Thank you for sharing your knowledge and experience!

  4. I have a lamp with resin and wood. the resin is cracking up and the wood pieces are coming out. If I want to fix it, I can try to mix a new batch and pour over the old resin. Do you think it will help?

  5. Hi, i have made mixture of granite, silica powder,and polyester resin, and added catalyst & cobalt to make hard this mixture, material is hard properly at that time no any crack found but after 1 month on this plate crack observed, i cant understand why it happens,
    can you please help me for that

  6. Had river table 120” by 8”. Used deep pour. Had a crack to substrate about 6” on width About 1/4” wide. Used deep pour to prevent. 2” thick. Baffled.

  7. I’ve done quite a few resin projects but just recently gotten into making jars. I made 2 beautiful and flawless mushroom jars! On #3, my resin started getting super hot and smoking! I cooled it down as quickly as I could but all around the bottom looks like a busted windshield 😭 do you think I will be able to fix this or will I need to start over? It makes me so sad! This was going to be the first jar I’ve made that I’d actually get to keep for myself 😭🤦‍♀️

    1. Hi Nikki, I’m afraid there isn’t a way to fix resin when it looks like a windshield. 🙁

  8. It’s been a while since I am doing resin projects but every project I do the base layer always crack like a glass ,even pieces come off.I work in the kitchen so I am now thinking can or be because it’s hot there and that is contributing into that.I was told it’s good that the temperature is high but all my pieces r cracked and when I try to fix it gets areas where resin don’t stay no matter what I do so at the end my pieces r wasted .Any suggestions how to handle this as resin here is too expensive and I’m doing my paintings on it and losing my work

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