Smoothing PLA with Sandpaper

Smoothing PLA with Sandpaper


Hi, Welcome to Tinkerine Experiments. This
is a new series where we will take different myths and rumors around 3D printing and test
them out for ourselves. Today we are going to start things off with
something simple. We will take these PLA prints and some sandpaper to try to polish the surface.
We have 320 grit sandpaper which is very fine and 100 grit sandpaper which is very rough.
Since we know PLA starts to soften around 60 degrees celsius. We will be trying out
a few methods. First of all, sanding non-stop and sanding periodically which is
every couple seconds to let it cool down and see if there is a difference. We will also
be trying dry sanding and wet sanding to see if the water will help cool down the temperature on the PLA model.
Here are the PLA prints before the post-processing. I can feel the PLA heat up on both methods
but it is less hot when periodically sanding. I can also feel the PLA soften under the heat.
This is the same when using 320 grit sandpaper. Let’s take a look at the results. 100 grit
non-stop sanding looks rough but it is actually smooth to the touch. You can see the PLA smudge
and the surface is very stringy. The same can be seen in 100 grit periodically sanding,
not much of a difference. 320 grit non-stop sanding looks smoother and
less PLA smudging and the stringy surface that we saw in non-stop.
320 grit periodic sanding looks relatively the same as non-stop. Surface is very smooth.
Let’s move on to wet sanding. For wet sanding non-stop and periodically,
I can’t tell if the PLA is smudging on the surface or not but there is definitely no
heat in sanding with both techniques. The same is seen in 320 grit sanding. We will
just have to see with the results. Moving to the results.
100 grit non-stop wet sanding is a bit scratchy but the surface is really smooth.
100 grit periodically wet sanding achieved the same results as non-stop.
320 grit non-stop wet sanding is very fine and smooth, and we don’t see the stringy and
smudging on the surface like dry sanding. Last in line, 320 grit periodically wet sanding
achieves the same results but it takes a bit longer. Here is a summary of all the sanding. Well there you have it, we post processed
these two PLA prints with dry sanding and wet sanding. From our observation, it seems
like wet sanding produces a better surface finish than dry sanding. 320 grit sandpaper
also produces a finger and smoother surface than 100 grit.
Therefore if you are looking to post-process your prints with sanding, I would recommend
wet-sanding. If you liked our experiment, like and subscribe
below and leave a comment on what experiments you would like us to try in the future!
Thank you for watching.

21 thoughts on “Smoothing PLA with Sandpaper

  1. ok.. you just have no idea how to use a wet sandpaper… you let it sink for a couple minute, and you don'T need a constant flow of water, you can use a bowl for god sake…

  2. Could I work up to 1500 grit and get really smooth and shiny results or is there a limit due to the material structure?

  3. Pretty nice tests.. but seems you don't know some basics of sanding.. you up the grid on every few passes. Each next grid removes the marks from previous. If you change direction of sanding on each grit change you can see when the scratches from previous grit are removed. Also use a much higher than 320 to finish. For wet sanding you only need to wet the sandpaper every now and then.. no need to have constant flow. Wet sanding will produce more fine finish as it removes any debris that scratch the model as you're sanding – also it will prevent sand paper from clogging.

  4. This is a great video. You've saved me the trouble of experimenting with different methods myself. Thank you for your work ๐Ÿ™‚

  5. i gonna made more test tomorrow but i find an "easy way" to sand pla with using hot water instead of cold water ๐Ÿ™‚

  6. Okay so… wetsanding under running water is pointless. The entire point of wetsanding is to build up grit under the sandpaper that is lubricated. When you do this under running water, you're literally washing away any grit buildup as soon as it forms. You might as well be trying to sand with your barehand. Proper technique: let the sandpaper soak in warm, soapy water for several minutes until it's completely saturated. Then apply sandpaper to object with light pressure until you feel the friction "break", once that happens, rinse (and repeat if necessary). Always rinse between different size grits as well, otherwise you'll still be sanding with the same grit of the former paper…

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