how transparent is transparent filament?

[Zak Kus]

I was looking for some "clear" filament, to effectively provide a little window. Makerbot sells some translusent natural pla. Has anyone used this? How "translucent" is translucent.? Clear enough to see whats inside, or is it really just intended to let light (like an led lamp) through?

[notstarman]

I cannot talk about makerbots filament directly but natural pla can be crystal clear.

The issues is that it no matter how clear pla is it still refracts light. This causes light to be slightly redirected every time it enters and leaves the pla. Because a 3d printed object is made of hundreds of layers resulting the resulting finishes similar to privacy glass. So it may not be what you were expecting.

I would suggest printing a mold and using a clear resin to cast your clear object.

[musk]

This is a diagram from Taulman using their t-glase material, but it also explains a similar principle with clear PLA.  You'll get clearer results from using larger layer heights that produce fewer internal reflections.

[Franc Falco]

So on a standard rep 2 with a 0.4 nozzle the max layer height would be 0.4mm?

[Ryan Carlyle]

Layer height needs to be less than nozzle width, or it won't mash plastic down and it won't stick between layers.

You CAN however tell your slicer that your nozzle is wider than it actually is. You may need to slow down printing speed but otherwise that works fine because it will just push more plastic out. With a 0.4mm nozzle you can set a nozzle width of, say, 0.6mm and a layer height of 0.45mm.

[Zak Kus]

Simplify3D does an interesting thing if you set the layer height too high. It'll warn you with a message:

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Unusual Width/Height Ratio

The chosen layer height and extrusion width settings have resulted in a primary width/height ratio below 1.2.

This is typically not recommended and may cause poor layer adhesion.

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that 1.2 ratio seems like a good rule of thumb

[sy mark]

I have Makerbot natural PLA and prints look exactly like they do on their website.  It's not clear like glass, more frosty than anything even on a single layer.  Notstarman explanation sounds logical.