One of the standout traits of filament printing is that it gives you a wide choice of materials to play with. You can select between materials like metal, PLA, and even conductive filament to create prints with specific characteristics.
When selecting filament it is important to note its individual characteristics. While PLA is easy to print, it is also notorious for being brittle. Nylon is strong but hygroscopic and polycarbonate produces a print almost as strong as metal without being as heavy.
Whatever the requirements of your project, you need to choose the appropriate material. For example, items intended for outdoor use need to be temperature and moisture-resistant. In this case, you would use a material that is UV resistant. But which material would you pick? Find out in this guide where we explore UV-resistant polymers.
What Filament Won’t Melt In The Sun?
Heat resistance is a necessary characteristic of 3D prints produced for outdoor use. ABS and ASA have high glass transition temperatures so will not melt in the sun. This makes them adequate materials for producing 3D prints like tools or fixtures that will be exposed to heat from the sun through outdoor use.
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What Is Glass Transition Temperature?
The glass transition temperature is an important metric used to measure the heat resistance of a material. It is the temperature at which material goes from hard to soft when exposed to heat. Source
When considering materials, we use glass transition to evaluate the heat resistance and therefore the suitability of a material for outdoor or other use where heat is a factor.
Acrylonitrile butadiene styrene (ABS)
ABS is the second most commonly used filament behind PLA. While it has a tendency to warp and is slightly harder to print than PLA, ABS will give you stronger 3D prints. Both PLA and ABS are regarded as being more suited for indoor use due to their lower temperature resistance.
With that said, ABS is a cheaper material for outdoor prints. ABS has a glass transition of 105°C. While it won’t melt in the sun but it is not the best option for outdoor use. For outdoor prints, ASA is a much better option.
Acrylonitrile styrene acrylate (ASA)
ASA is a filament specifically developed for outdoor use. It is also used to produce parts for the automotive industry. Compared to ABS, ASA has a higher UV resistance and can retain its shape and color for much longer.
ASA has a glass transition of about 110°C. On the whole, ASA prints will stand up to heat from the sun much better than ABS. ASA is used to make items that undergo intense heat like car cup holders and outside sprinkler heads for example.
Will PETG Melt In The Sun?
PETG is an improvement on PLA for producing outdoor prints. It is as easy to print but with the distinction of having a higher glass transition of about 85°C compared to 65°C for PLA. It will not melt in the sun. It does, however, have a lower glass transition than ABS (105°C).
Polyethylene terephthalate glycol (PETG)
PETG is a derivative of PET, the material used to make plastic bottles, fast food packaging, and up to 30 percent of the plastics we use. Glycol is added to the PET to improve its strength and durability.
Compared to ABS, PETG is less prone to warping and does not present as much of a challenge when printing, especially for beginners. Source
Does PETG Block UV Light?
PETG has a higher UV resistance compared to similar filaments like PLA and ABS. While ABS has a higher glass transition, PETG typically performs better outdoors. The difference between them is that UV radiation from the sun tends to discolor ABS prints faster. This is one of the reasons why it is less favored for outdoor use.
Which Is Stronger ASA Or PETG? Vs UV
ASA is a 3D printing filament with high heat, UV and chemical resistance. These qualities make it the standout choice for outdoor applications. It is, however, more difficult to print with. While PETG is a stronger alternative to ABS, it does not perform as well as ASA with regard to heat or UV resistance.
ASA outperforms most materials when it comes to weathering. Aside from being harder to print with, the only other disadvantage to ASA is the higher price. ASA is more expensive than either ABS or PETG. That being said, if you need a material that will last the longest for outdoor use, ASA is the best option.
Does PLA Degrade In UV Light?
PLA does not degrade when exposed to UV light. It does, however, display poor performance when exposed to heat due to its low glass transition (between 60 to 65°C). Poor heat resistance is the main reason why PLA is more suited for indoor use.
Of the four materials we have covered, PETG, ABS, ASA, and PLA, the latter is the least suited for prints that require temperature and UV radiation resistance. PLA melts much faster than any of the other materials.
For example, if you were printing a light fixture or candle holder, PLA would not be your first option. While it might work depending on the temperatures, it would not hold up as long as either ASA, ABS or PETG.
How Long Does PLA Last In The Sun?
PLA has a low heat resistance and a short lifespan when exposed to direct sunlight. Indirect sunlight does not have as severe an impact. Direct sunlight typically weakens PLA prints, causing them to warp or melt.
For example, a car cup holder printed from PLA can deform and lose its color within a few hours due to the high temperatures inside a car.
How Do I Protect My 3D Printing From UV?
Protecting a 3D print from UV can be approached in two ways. The first would be to strengthen the print through heat treatment. The second would be to reduce the exposure of the print to UV by simply painting it or coating it in another material.
Paint is possibly the simplest fix. Paint not only improves the appearance of an item, but it can also protect it. For example, painting a 3D print in a bright color will reflect light and heat whereas a dark color will make it more absorbent.
Paint provides a layer of protection from direct exposure to sunlight for an outdoor print.
Annealing is a heat treatment technique that improves the material strength of a 3D print. Annealing involves heating a material to just below its melting point to let the material relax. Heat treatment is said to be especially effective for strengthening PLA prints.