We Are Learning 3D Printing Through Our Personal Experience…
One of the drawbacks of the FDM (FFF) 3D printing method is that the result of your printing is a model that is not totally smooth to the touch, you can see and feel the texture created by the layer by layer printing by extruding the thermoplastic material. The smaller the layer size the less noticeable the texture of the printed 3D model is, but it is till there and some people just want to get a smoother glossy or matte object as a result of their 3D printing. There are multiple solutions for smoothing the surface of your ABS or PLA 3D prints to make them look even better as a final product and not seem so much like they were actually 3D printed. The most commonly used approach seems to be the use of various solvents that can help you get a smoother look of the surface of different 3D prints, but you need to be careful with these as solvents might be dangerous to your health and if not properly handled you can also damage your 3D printed models.
One of the most commonly used methods for smoothing the surface of 3D prints made with ABS material is to use Acetone as it melts the ABS plastic and creates a smoother and glossy looking surface. The there are various ways for the application of Acetone for smoothing ABS prints that may produce varying results, so you might want ot try them all and experiment to see what works best for you and gives you the best results. Some people dip the model in acetone, some apply it on the model with a brush and some use Acetone vapors to melt the ABS plastic and give it a smoother finish. Regardless of what you use however you should be careful with Acetone and try to avoid inhaling and also be careful as Acetone is highly flammable. Another alternative to Acetone that might give you the same results for smoothing ABS prints is Methyl ethyl ketone (MEK), also known as Butanone, as some people report successfully using this instead of Acetone. Do note that Acetone and MEK do not seem to work well with PLA filaments like they do with ABS, so do not try them for smoothing PLA 3D prints!
For smoothing the surface of PLA 3D printed objects it seems that so far the best working solvent providing similar effect to Acetone for ABS is Tetrahydrofuran (THF). THF not only works for PLA like Acetone does for ABS, but it also smells similar and might be as dangerous as Acetone to your health if you do not properly handle it, so you should be extra careful when working with any of the solvents mentioned here. It is a wise idea to wear gloves and work in well ventilated area, so you will not be inhaling the fumes of the solvent you are working with, also be very careful when handling any of the mentioned solvents – Acetone, MEK or THF as they are all very flammable. Do note that Acetone is the easiest and most widely available solvent of the mentioned ones and you may have trouble finding or obtaining any of the others mentioned, so do check locally if they are easily accessible.
Another safer for handling alternative that is supposed to work with both ABS and PLA 3D print (as well as many others) is a special product dubbed as high performance 3D print coating called XTC-3D from Smooth-On. It has been getting some attention lately among the 3D printing community, though people are reporting mixed results after trying it out. The product is essentially an epoxy coating consisting of two liquids that are mixed together and then brushed onto any 3D print, the coating is supposed to self-level and wet out uniformly without leaving brush strokes. Working time is 10 minutes and cure time is about 4 hours and after that the XTC-3D should have cured to a hard, impact resistant coating that can be sanded, primed and painted. The problem with the Smooth-On XTC-3D is that it is not widely available, might be easier to obtain in US, but we could not find it available anywhere in Europe or a place to order it from that will deliver here, so that could be a serious problem. Other alternatives include priming and sanding the model and then maybe painting it or painting with PlastiDip rubber like coating directly.