How to get a smooth finish on a PLA printed part

[Jules]

No arguments here.....had a near fatal experience with lye and an unexpected gust of wind ten years ago...now I keep everything from the little doctor's ear-loop masks to full face Israeli M15s, although I'm hoping to be able to keep it dialed back to a half-face NIOSH 6001 filter....aside from being uncomfortably hot and limiting your vision, it tends to scare the neighbors if you run around in an M15.

Since I don't have a fume hood, I'd prefer to do that kind of thing out back on the deck anyway. It's wired. (Don't want to kill the cats either - they live in the garage.)

What masks have you found that work best for this kind of fumes?

[ajmadison]

Someone suggested that I sand plastic with wet paper and submerge the part in water while sanding, to avoid fine plastic dust in the air you are breathing. I have no idea how important this is, so it sounded sensible to me at the time, and that is what I've done the few times I've tried.

I must say I have never heard of that! I work as a modelmaker, so I like to think I have heard it all when it comes to sanding techniques. All this does is sound...inconvenient.

The water or polishing fluid is there to lubricate the surfaces and cool down the part to prevent any...ugliness. if you are sanding something and creating so much dust it becomes and issue, use a dust mask. that won't get in the way of your...wrist action...like working against water would.

if you are sanding flat sided elements, put the paper on a level block/table and work the piece on top of it, in a figure of eight movement. it maintains the flatness and should stop you from creating a bias to one side.

FYI, another model making trick is to put a drop or two of dish washing liquid in your water for a wet sand. Dish wash liquid is or has a surfactant in it. A surfactant reduces the surface tension in water, in other words, makes better contact between the water and your sandpaper and the object to abraided. Makes the wet/dry paper last longer because the abraided particles are less likely to get stuck in the paper, and the abraided particles are lifted from the sanded surface. The surfactant properties is also why a couple of drops of dish wash liquid in water is the recommended lubricant for applying Kapton tape to the heater bed.