QUESTION: I have a 3D printer that works in ABS plastic but sometimes with internal overhangs the plastic strings don't stick together as well. I was wondering if there is a glaze that can fill in gaps of a surface and give it a somewhat finished look?
If the nozzle is too far away from the bed, the bottom surface can show unwanted lines, and/or the first layer might not stick. Does this sound like the problem?
If this is the case, you can try using your printer's software to re-level the print bed. Cleaning the the bed of fingerprints, can help, as can applying a fine film of glue to the bed before printing.
Or is this a case of "Over-extrusion", meaning that the printer supplies more material than needed. This results in excess material on the outside of the model printed. If this is the case, it can be due to the extrusion multiplier or flow setting in your slicing software being set too high.
If neither of these scenarios sound like your problem, can you send me a picture of a printed sample that has the problem you described?
I hope I've been a help,
---------- FOLLOW-UP ----------
QUESTION: No my machine is well calibrated, but like most extrusion 3D printers there is a limited range of degrees before there are overhang issues. I made a hollow dome shape and the inside gets a little messy. Is there a glaze that would smooth it out on the inside? The inside won't be seen much but I would still prefer it appear more finished even if the color and texture is different. I just want to fill in tough areas that can't be sanded.
There is a process that uses Acetone to smooth ABS plastic. You can read about it, and watch a video on the subject here:
Although there's no heating involved in this process, you don't want to do this anywhere near open flames! Acetone vapors can explode!
Alternatively, there is a two step epoxy coating called "XTC-3D Epoxy" used to smooth ABS prints. Another product to consider is "Z-Poxy PT-39 30 Minute epoxy". I'm not at all sure if any two step epoxy product (resin and epoxy hardener) will work just as well. It might be worth experimenting with.
Read about it here:
---------- FOLLOW-UP ----------
QUESTION: I have done the acetone steam cooker method to smooth some models, but I am not looking to melt the plastic. The inside of the dome is a lot of loose threads that didn't quite take because it's nearly at 0 degrees. I want to make it not bristly up in there, and don't mind if it is an opaque coating inside. It doesn't need to be 3D printing specific. Could be a more general art product. Any other suggestions?
I would first remove the threads with some 400 grit sandpaper, then try using Acrylic medium of some sort to fill the gaps.
There are several kinds of acrylic mediums, since I still haven't seen a picture of the piece you're referring to, I can't suggest a specific kind.
You might consider a self-leveling gel medium, or molding or modeling paste mediums. Molding and Modeling pastes come in a range of viscosity as well as hardness.
Other things that might work are:
Silicone aquarium sealant
Plastic Wood wood filler
Acrylic Plastic Filler
Fine Surface Speckle (the kind used to fix small holes in a wall)
I hope that helps.