Take a look at this really interesting video of an experiment to seal Shapeways 3D printed Nylon with super glue and acetone.
Shapeways community member and Twisty Puzzles Forum member Brandon Enright has shared a really interesting video on YouTube of his experiment to seal a Shapeways Nylon (WSF) 3D print with a mixture of Cyanoacrylate (Super Glue) diluted with Acetone. His experiments show that the mixture quickly penetrates and seals the surface of the nylon giving a glossy texture that is considerably more resistant to getting dirty when tested with tiny particles of copper powder. When compared to unfinished nylon parts there was a massive difference. This is a well documented experiment that is showing some very promising results and we are really looking forward to seeing more results. We also know that people are using floor polish to get a similar effect but you may need to be careful the formulation you use does not yellow over time.
What post processing experiments have you tried on your Shapeways 3D prints? We would love to see more videos of your results.
People in the woodworking and pen turning communities often use CA glue to seal and coat their smaller turned wood products after they are turned on a lathe. CA glue is generally available in thin, medium, and thick formulations. The thin formulation flows much like water, medium clings to a surface and flows slowly, and thick flows even more slowly. The viscosity differences between the formulations are primarily caused by the sizes of the molecules in the formulations and less by the extra fillers in the bottles. Accelerants in spray bottles are also available from the glue manufacturers which will harden your CA glue almost instantaneously. It's not a good idea to swing the wet part around in the air and risk getting droplets of glue in places where you don't want them!
I have experimented using thin CA glue to seal alumide which appears to be much more porous and absorptive than WSF. I would imagine that you could further dilute the thin CA glue with acetone although I find CA glue fumes to be rather noxious and adding acetone would make things worse - especially without a fume hood! Anyway, I have simply dispensed the thin CA glue from the bottle over my alumide test piece to wet the entire piece and then quickly dabbed off the excess with a paper towel. One application should be sufficient unless you want to add shine and thickness. If you dab quickly and thouroughly you won't have any glossy spots and should end up with a finish that is slightly darker than what comes out of the machine (at least for alumide). If you are too slow to dab you may end up with some paper towel lint attached to your item. I suspect that the acetone thinning method shown in the video might also benefit from the dabbing process to make the finish more uniform with less gloss.
Don't forget to always use protective eyewear, rubber gloves, and have good ventilation when using these noxious chemicals. Safety first!
I've only tried it once and I believe I used "Stick Fast" thin CA glue which I probably got at Woodcraft or Menards. Rockler Woodworking also has equivalent CA glues sold under their brand name.
There are also many other products and techniques that woodworkers use that may be considered. Most will probably affect color since they are intended for wood. Some might dissolve your plastic so don't try them on anything that is too valuable! Here are a few that come to mind that people may want to try.
1. MinWax wood hardener. It's a liquid that is meant to soak into wood and stabilize it for repainting. A soaking, quick dunk, or application with a brush should work, followed by dabbing. I have only used this stuff to harden and stabilize the surface of chalk. It's not glue so you don't have to race against the clock to coat and dab it. It should be completely dry after a few days.
2. Lacquer sealers such as the Penn State Industries glossy lacquer sealer. I have tried this on WSF but it will cause the white to turn slightly yellowish brown almost like ivory, but it prevents other oils, greases, or sweat from penetrating the plastic later. 1 to 3 coatings with dabbing between each coat leave a nice matte finish. I am about to try this on some black strong and flexible and dyed items.
3. There are a whole mess of other products that I have not tried that are meant for penetrating and coating wooden bowls or cups so they are non-toxic when dry. Many are also water based which means fewer toxic odors. I have not yet tried these.
4. If you want to do some mad sientist experimentation I have also read about people stabilizing wood by using acrylic plexiglass dissolved in acetone into a mix with a consistency of water. It should provide similar results to what was shown in the video but would require more drying time.