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How To Harden 3D Printed ABS: The Complete Guide

ABS isn’t always the easiest filament to print with since it has unique thermal properties that make it prone to warping, some printer errors, and an overall weak structure. However, there are ways to harden your ABS prints after peeling them off the print bed that will drastically improve the durability and appearance of your 3D printed objects. 

Here are the best ways to harden 3D printed ABS: 

  1. Anneal the ABS with heat.
  2. Harden the ABS print with epoxy. 
  3. Bathe your ABS in acetone vapors. 

This article will look at the best methods to harden ABS prints. It will also outline the be printing settings to improve the strength of your ABS prints and discuss possible more robust alternatives to ABS for 3D printing.

1. Anneal the ABS With Heat

Annealing ABS involves applying the right amount of heat to the material to recrystallize it, giving it more structural strength. 

During this process, the thinnest parts of your print, such as strings, overhanging layer lines, and badly fused layers, will get warm and soften, while the thicker parts of your model will stay solid. As these finer details soften and shift a bit, they increase layer adhesion and reduce the appearance of layer lines, helping you get a solid print.

ABS has a glass transition temperature of 221 °F (105 °C), and you’ll have to heat it at just below this temperature to get only the thinnest parts to soften. You can then cool it down slowly and let it crystalize to harden. 

While you can use a specialized heating machine to anneal your prints, a regular oven will work just as well. 

Simply heat the oven to the correct temperature, stick your print inside, and leave it for 30 minutes to soften. Use fans to cool it down once the heating process is complete. Since ABS will only melt at 410 °F (210 °C), you don’t have to worry about it melting in the oven! 

Annealing can increase both the strength and stability of your 3D prints. It can also improve the heat resistance of your objects. If you’re only printing a model, there’s no need for annealing. However, if you need to print something for practical use, it’s better to anneal it first. 

2. Harden the ABS Print With Epoxy

Epoxy is one of the most durable materials and resists pressure excellently. So, you can apply an epoxy coat to strengthen your ABS prints and make them less brittle. 

Epoxy glue also has excellent adhesion and can form a protective layer around the material, strengthening weak points. 

There are a couple of ways you can use epoxy paint to strengthen your ABS prints:

  • Coat your ABS prints with a brush. Apply a coat or two on the material’s surface to strengthen it. Wait for the first coat to dry before applying the second coat. Simply painting on epoxy is the easiest way to spread it on your prints, but it can be messy, and you might get streak lines from your brushstrokes. 
  • Immerse the ABS print in epoxy. Let the epoxy soak into the delicate areas of the print and leave it to dry for hardening. Dipping your model is a great way to make your 3D ABS prints as hard as a rock! However, you can’t use it for all ABS prints as the epoxy may damage the print’s finer details when hardened. 

If you are looking for a reliable epoxy that will stick well to ABS, check out this Smooth-On XTC-3D Epoxy (available on Amazon.com), which will work on all your favorite filaments from ABS to PLA and most other rigid materials. This two-part epoxy is for 3D printed parts, so it provides the best, most reliable outer shell with a durable texture. 

3. Bathe Your ABS in Acetone Vapors

Acetone vapor can strengthen the density and rigidness of ABS prints. However, acetone can also dissolve ABS, so you’ll need to be careful if you choose to use this method. Still, since ABS is sensitive to the chemical, it makes for a fast turnaround time. 

To use this method, you’ll need a glass container, a bunch of paper towels and tissues, and a glass plate or some aluminum foil. 

Here are the steps for hardening ABS with acetone vapor: 

  1. Soak your tissues and paper towels in acetone. 
  2. Place the wet paper inside your glass container, then place a couple of pieces of tape over the paper towels or tissues to secure them.
  3. Place your ABS model on a glass plate or sheet of aluminum foil.
  4. Flip the glass container over and place it on your ABS print. The acetone-soaked paper should not touch your print. 
  5. Allow the print to soak in the vapors for around 15 minutes. 
  6. Allow the ABS print to air out, and don’t touch it since it will be slightly tacky and soft. 

Check out this detailed tutorial that will teach you how to bathe your ABS prints in acetone. 

Frequently Asked Questions

Do ABS 3D Prints Break Easily?

ABS prints don’t often break if printed with the correct settings. ABS is more durable than PLA and other standard printing plastic filaments but can be brittle and break under pressure. ABS should never be used to print practical parts without first ensuring the print can handle the application. 

While ABS is a strong plastic, it’s still plastic and will break if you put enough pressure on it. However, you can strengthen ABS prints to make them more functional. 

Sometimes the print’s design can affect how durable the model is, as can the printing technique. So, while the print material does affect the strength of the final product, it’s not the only factor to consider. 

How Do You Achieve Stronger ABS Prints?

While strengthening your ABS prints is a good practice, optimizing your 3D modeling design for impact resistance is always best. Following the correct print settings for quality prints will result in more substantial and durable prints. 

You can achieve stronger ABS prints by altering your CAD design and adding reinforcements, infill, and thicker walls. Adjusting your 3D printer settings can also increase your chances of better layer adhesion.

Here are some tips for printing ABS models that will stand up to pressure: 

  • Set the correct printing density. A higher print density will result in better quality prints. However, take care to avoid warping. 
  • Add thicker layers to the prints. You can tweak the print settings to create thicker layers, resulting in more durable 3D printed objects. 
  • Print at a slower speed. Printing at a slower pace can improve the print quality as there are fewer air gaps in the models. 
  • Cool the print correctly. Did you know the method used to cool the model down can affect the print quality? Use the fans at a lower setting to allow the print to cool down properly, and you’ll get more rigid walls and better layer adhesion. 
  • Use better quality ABS material. The quality of your ABS filament matters a lot in 3D printing. Be sure only to purchase 3D printing filaments from reliable manufacturers. 

Conclusion

ABS is an excellent material for 3D prints but can be brittle at times. You can strengthen your 3D printed parts by annealing the ABS with heat, applying an epoxy coating, or using acetone vapor. 

However, strength starts at the design phase of 3D printing. So, if you want your ABS prints to be durable, be sure to use the correct print settings for ABS and add some thickness and infill.