Someone mentioned this to me on an off hand comment.
Basically using methylene chloride in a metal container with a glass roof which is then gently heated until it turns to a vapour. The vapour “melts” the top surface smoothing it out giving a great finish. I know it works with only certain types of plastics and was wondering if anyone had played with it with the form labs resin before I go and buy some?
FYI methylene chloride is VERY nasty stuff so make sure you take appropriate precautions with it!
I’m basically looking to find a good way to finish parts with a lot of little details that mechanical sanding would just be impossible on.
Thanks for carrying out the test. I suspect that if acetone didn’t cause the polishing effect then something more aggressive also wouldn’t unless there’s a chemist in the building that could say otherwise?
Other techniques that jump to mind would be flame polishing or even just a very gentle oven bake but these obviously have their own issues when it comes to the dimensional stability of the model.
Here’s a pic of the kind of thing I’m looking to print off and polish up and as you can see, polishing in amongst all the details would be a right pain manually!
I have had the little one for a couple of decades now and it works really well really quickly to take off build lines without destroying details. It will leave a mat finish behind.
Personally I would be weary about using any kind of solvent on plastic, you don’t know what it does to the material over time. Cooking chemicals in your house doesn’t sound like a very good idea.
That would depend on the type of part, some may be too fragile.
Air eraser works really well, if you have a big plastic container you can spray towards that to gather the media and re-use it. The media doesn’t float around but you should wear some sort of mask so you don’t breath any in.
Since this is a UV cured resin, it will be tough to find something safe that will smooth it like acetone does with ABS. For the example part in the pic an easy way to make it shiny would be to dip it in resin or paint it on and then cure it in sunlight or a UVoven. It gives a smooth shiny surface as seen if you have ever repaired a part with resin or simply had a drop of it cure on something.
If the part is real “ridgey”, you could sandblast first and then coat it.
Best bet is to sand or use an air eraser to clean up and smooth the surface then for a shiny polished surface spray a light coat of varnish. Many shops that print from polyjet printers use an acrylic varnish to give it that gloss look.
