What's smoother? Acetone treated PLA or ABS
From my understanding, both PLA and ABS can be treated with acetone to make them smoother. So when they are treated with acetone, which is smother PLA or ABS or are they about the same?
When I search online, all I find is how to treat the objects.
@tjb1 That is not quite true. I have noticed that a PLA part (which I used as a stand when smoothing ABS parts) did get noticeably smoother after a few uses. I'm not sure if that's due to the PLA being impure, but I'm not convinced PLA is entirely insoluble in acetone.
@TomvanderZanden soluble would indicate that the material dissolves in the liquid. I've never seen any of the PLA I have dissolve in Acetone and I've not found anything online that shows it dissolving or changing the color of the Acetone. I have found references to PLA swelling in Acetone but not dissolving.
Just to clarify, you say `When I search online, all I find is how to treat the objects.` - by *objects*, do you mean the finished printed items? Do you want to smooth the printed items, or something else (i.e the filament itself)? Or are you saying that the articles that you found only describe how to *treat* the prints, but they do not *compare* the smoothness of treated PLA and ABS? I guess you mean the latter. This article Acetone Finishing on PLA has some good points raised in the comments about whether PLA can be treated
@TomvanderZanden Most PLA filament has additives, sometimes including ABS, sometimes just dye. Often, those additives dissolve in acetone. I have never been happier with the result after trying to smooth PLA with acetone than I was before I started. Usually, it just seems to permanently soften and become porous, which is not a good look.
ABS filaments will smooth well with using acetone, it's been used for a while now.
For PLA filaments it's a different story, pure PLA will not smooth out in acetone and it will likely only cause structural failure of the product.
However most PLA filaments aren't pure PLA, they contain additives including ABS that react differently when exposed to acetone and the reaction will really depend on the manufacturer of the filament, only a few PLA filaments are known to smooth like ABS when in an acetone vapor bath, it is the case for ColorFabb PLA filaments and it is absolutely not the case for bq PLA filaments that only soften and break when exposed to acetone.
You'll have to make small tests with different brands of filament to see which smooth well and which don't but if you want to go fast either go with ABS or use other smoothing techniques such as sanding + 3D print Smooth On epoxy.