What is the smoothest plastic available (like glass)?

[cadenza]

Hello all,
Does anyone here know of a plastic to use that is extremely smooth for 3D printing? I'm talking about something that is as smooth as glass when you touch it. You shouldn't feel any rough texture on it when you touch it. I'm new to the 3d printing scene and am trying to understand the types of plastics out there.

I appreciate any help I can get for this.

[fred_dot_u]

One can print with ABS which would have the typical layer lines. After the print is completed, a method known as acetone smoothing will remove those lines and create an extremely smooth surface. It's important to note that using this method will result in some dimensional changes to the item, as part of the surface is dissolved and flows into adjacent areas. I've used the hot vapor acetone smoothing method of many objects and the results are very likely what you seek. There is another product of which I have no experience. Polysmooth is similar to PLA and vaporized isopropyl alcohol is used to make the surface smooth. From the linked site, I see that one can also spray the alcohol on the object multiple times to create the smooth surface. The product is more expensive than ABS or ordinary PLA.

[cadenza]

Thank you, Fred. I looked up some videos on YouTube on acetone smoothing. Looks like something I can try. I appreciate the very detailed response.

[fred_dot_u]

If you have the resources, consider to use the hot vapor method. It's faster than the other options and I feel the results are more consistently good. All this is done outside as the vapors are dangerous to one's health and also explosive. I used a large glass cookie jar in a double-boiler configuration. In my case, it is a hot plate with a frying pan filled with water. The acetone occupies only a few millimeters of the closed glass jar. One can view the internal condensation of the evaporated acetone on the glass. Once the level reaches the height to manage the object being smoothed, it is lowered into the vapor for twenty to thirty seconds. It is necessary to construct a secure object caddy. A piece of wire mesh such as hardware cloth will work, along with a wire cage to keep one's hands clear of the vapors. Any contact of the item with the caddy will leave a mark, which means one should aim for small contact points in unobtrusive locations. One of my better results can be found on Thingiverse, in the shape of a banana.