You 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 bat. What’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
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.
Hi Dorothy, it sounds like you might be using doming resins for your cubes. Our deep pour casting resin is a great choice for a project like this. You can buy it in our store here: https://shop.resinobsession.com/collections/resin/resin-obsession-deep-pour-resin
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
Hi David, it sounds like your resin is getting too hot.
how would I find a person to fix my jade table with a crack in the resined top
Hi Sara, you can put your request in the commissions section of our forum. One of our readers may be able to help you: https://resinobsession.com/forums/forum/commissions/
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!
You’re so welcome, Beth. I’m glad we can help you with your endeavors!
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?
Hi Sona, the new resin should stick to the old resin provided the surface is clean.
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
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.
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 😭🤦♀️
Hi Nikki, I’m afraid there isn’t a way to fix resin when it looks like a windshield. 🙁
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
Thnx
I made a beautiful resin countertop river table for the bathroom. Then I dropped It and cracked the corners. I’m so mad. I’m hoping I can Somehow fix it.
I did an old time looking Santa on an antique window about 2 years ago. Sold it to a friend and she had it hanging in her home. Talked with her today and she said there is a crack in the resin. What could have happened and can this be fixed. If you rub your hand over the crack you can feel the crack.
Thank you
Debbie
A crack in the resin on your Santa art piece could have been caused by several factors, and the good news is that it can likely be fixed! Let’s explore the potential causes and a step-by-step solution to restore it.
Possible Causes of the Resin Crack
Temperature Fluctuations:
Resin can expand and contract with temperature changes. If the window was exposed to extreme heat or cold, this could stress the resin and cause a crack.
Improper Mixing or Application:
If the resin wasn’t mixed properly or applied too thickly, it may not have cured evenly, leading to weaknesses that developed into cracks over time.
Movement or Pressure:
If the window flexed or experienced pressure (e.g., during cleaning or hanging), the resin layer might have cracked.
Aging or Resin Type:
Some resins can become brittle over time, especially if exposed to UV light or if they weren’t UV-stabilized.
Steps to Fix the Crack in the Resin
1. Clean the Surface
Gently clean the area with a soft cloth and isopropyl alcohol (90% or higher) to remove dust, oils, and debris.
Let the surface dry completely before proceeding.
2. Sand the Cracked Area
Lightly sand the area around the crack with fine-grit sandpaper (e.g., 320-400 grit) to smooth the edges and create a surface for the repair resin to adhere to.
Wipe away sanding dust with a clean, dry cloth.
3. Mix and Apply a Fresh Layer of Resin
Use the same type of resin you originally used, or a clear, UV-stabilized resin if the original resin isn’t available.
Mix the resin and hardener according to the manufacturer’s instructions.
Apply a thin layer of resin over the crack, extending slightly beyond the damaged area to blend it seamlessly.
4. Level and Remove Bubbles
Use a small brush or toothpick to spread the resin evenly.
Remove air bubbles by gently passing a torch, heat gun, or straw over the surface.
5. Cure the Resin
Allow the resin to cure fully according to the manufacturer’s instructions, ensuring the piece is placed on a level surface and protected from dust.
6. Sand and Polish (Optional)
If the repair area feels uneven after curing, wet-sand it with fine-grit sandpaper, progressing to higher grits (e.g., 800, 1200, 2000) for a smooth finish.
Polish the area with a resin polish or car polish to restore the shine.
Preventing Future Cracks
Temperature Control: Advise your friend to hang the piece in a stable environment, away from direct sunlight, heat vents, or drafty windows.
UV Protection: If the window is in a sunny area, apply a UV-protective spray or coat over the resin to prevent brittleness.
Proper Hanging: Ensure the piece is securely hung to minimize movement or stress on the resin.
This repair should restore the piece and ensure it looks great for years to come. Let me know if you need help selecting the right resin or tools!