How to Print Clear Filament, More Clearly

Clear 3D Printing. It can be a bit of an enigma, the success of your clear prints down to a number of things. If you’ve tried it before, ended up watching countless videos explaining how to 3D print transparent filaments and are still non the wiser – this ‘how to print clear filament’ guide should clear things up for you (sorry, although we can’t promise that will be the last pun in this article).

Different filaments have different tendancies, so it’s important you know what you’re dealing with to get the best results. What are you trying to print, how are you printing it, what are you printing it with – these are all questions to ask yourself.

 

Transparent PLA Filament

(Want the best translucency? Print 1 layer thick...)

The STL model:

It doesn’t matter how clear a clear filament you use, if the STL file you’re trying to print is solid or extremely complex. The clearest printing filaments won’t keep an internally complex model clear, no matter what you do. Because each layer of filament, each extra layer deep – that’s more and more light being dispersed inside your print.

For example, 1 window is pretty clear. But if you stacked 100 windows infront of each other, you’re probably not going to see a huge amount of light coming through the other end?

Each layer refracts the light further – so clear filament will never create perfectly clear prints unfortunately, simply due to limitations with your printer. But there are things you can do to improve the translucency, so that it will allow light to pass through it.  

If you want to make a model that’s got high translucency, we recommend printing very thin wall thicknesses (ideally only 1 layer thick), with no or very little infill.

Slow, Hot and BIG:

It helps if you print most filaments at the top end temperature that they’re recommended at, this keeps the definition between each layer as minuscule as possible. You may lose a little detail, but you should gain smoothness. And in this game (the printing clear prints game) smoothness means more light passing through.

You also want to print a little slower than normal. Ideally your printer wants to be very accurate, the more accurate your printer – the better your prints look typically, and the clearer they’ll look. Make sure your belts are appropriately tight, so that there’s no overshooting of the print head (even by fractions of a mm) that could lead to less accuracy.

Big layers. If your layer height is larger, you won’t need as many layers. So it may make sense to print thicker layer heights and even using larger nozzle sizes. However if your printer is really accurate, printing very thin nozzle diameters can also yield nice results on 1 layer wall thicknesses.

Which Filament to Use?

Let’s take a look at the various options you have in the form of transparent 3D printing filaments and the positives, negatives and best printing tips for each. The most commonly available clear or translucent 3d printer filaments are: PMMA, PETG, Clear (Natural) PLA, Clear ABS and Polycarbonate.

It goes without saying that you’ll get out of this what you put into it. If your using cheap, poor quality filament that isn’t either as clear as it could be, or pure resin for printing – then your results will be restricted. 

PMMA Filament

If you’ve used this filament before, you’ll know that it is a clear plastic acrylic material with high impact strength. Due to its strength and impact resistance, PMMA is commonly used to replace glass in certain applications. Typical PMMA grades allow up to 92% of light to pass through its surface, which is more than other plastics and, surprisingly, even glass.

PMMA is available in a nice range of colours, and prints quite clearly in comparison to other materials.

Clear ABS Filament

ABS isn’t naturally clear – like the other materials. This means that we need to blend it with an additive to make it clear. And by clear, really we mean translucent at best. If you absolutely need to print in ABS, then using clear or translucent colours of ABS is a good compromise – but ultimately it won’t print as clear as some of the other materials.

ABS can be post print finished with Acetone vapour smoothing though, which is a bonus. This means you can get the layers very smooth – which helps light transmission immensely.

 

Clear PLA Filament

(this RC Spitfire wing is printed in our clear PLA with a 1 layer skin)

Natural PLA Filament

A lot of natural PLA filaments aren’t actually clear, but the good quality ones are. Ours is about as clear as PLA gets, although it has a very faint yellow tinge to it which is natural with PLA - you can just see this in the Spitfire wing above. 

Again, like ABS, this is a commonly used filament. It also has the added benefit of being biodegradable, so less damage is inflicted on the environment, so you can feel a little better about yourself when using it.

Clear PLA filament is one of the easiest to print clearly and get good results. Good quality PLA can also be easily sanded afterwards – which for this material is the best way of getting a good smooth finish to let light pass through uninterrupted.

It’s important to use a fine grit, depending on the layer height you printed with. Thicker layers and you’ll need a courser sandpaper. Then use finer and finer grits, sanding in a circular motion each time (this bit is important, because you’re trying to remove all surface imperfections). Start at maybe 400 grit, and upwards in 200 increments from there. Finish with 3000 or higher grit to get a really smooth finish.

If you can do this on both sides of a print wall, you can get a very clear finish.

For best results make sure the sandpaper is wet, and don’t be too aggressive and heat up the surface by going too fast.

 

Clear Polycarbonate Filament

(printing the same 1 layer thick vase as above, but in PC)

Polycarbonate Filament

This is an extremely durable and optically transparent 3D printing filament that is best printed in a warm environment. Due to its durability, it can be bent repeatedly without cracking, making it great for creating all sorts of hipster jewelry that looks like it was made for a seven-year-old girl.

But seriously, Polycarbonate (PC) is immensely underrated material to print with. It finishes with a nice glossy sheen to it. It needs a very hot extruder to print it normally, and if you’re looking for translucent results, we’d recommend going even hotter still (300C+).

A great advantage with PC is that it can be smoothed with acetone similar to ABS to bring out clearer results.

 

PETG Vase

(vase printed in our Orange PETG)

PETG Filament

This is a really durable filament with excellent layer adhesion (almost unbreakable) and, with less shrinkage than other filaments; it’s great for printing big stuff that won’t break under pressure. The ladies love it. It is odourless when printing and often produces clear, smooth finishes. Thus making it the ideal material when you want something with a bit of flex that won’t break.

The colours we offer are very vivid for PETG. It can’t be smoothed with acetone though, and although it can be sanded – it doesn’t sand as nicely as PLA. You should find PETG prints quite nicely though, meaning it’s less likely to require post print finishing.

The final pep-talk

Transparent 3D printing is quite finicky business. Even the slightest miscalculation in nozzle temperature, printing speed and cooling can all affect how clear your print is. While it isn’t rocket science, there’s certainly a method to it.

It’s worth bearing in mind that each printer and filament often requires settings specific to itself, meaning what works for rigid.ink clear ABS might not work so well for Taulman’s T-Glase PET.

With that in mind, you’re really best getting one material you think will be most suitable to what you need and experimenting with printing and post printing techniques mentioned above to get the best results.

I hope this guide helped you, and as always – if you have any questions please don’t hesitate to pop them in the comments below. I’ll be happy to help.

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