Some preliminary experiments with THF smoothing of PLA prints

[madoverlord 0]

So after reading the http://www.protoparadigm.com/blog/2013/06/vapor-smoothing-and-polishing-pla-with-tetrahydrofuran-thf/ about smoothing PLA with http://en.wikipedia.org/wiki/Thf, I got some of the solvent and started playing.

It goes without saying that this stuff, like acetone, is nasty and should only be messed with outdoors, with a respirator, googles, and nitrile gloves on.

Anyway, I built a simple vapor smoother but I was not particularly happy with the results. Also it can form explosive peroxides if you let it dry out, and that's always a risk with vaporizing the stuff.

I tried the el-cheapo cold vapor method (solvent in the bottom of a jar, nuts and bolts to form a platform that keeps the part out of the solvent, no heat) but my initial results were not promising. By the time you get significant smoothing, the parts start to crack. There may be a sweet spot in timing but I flashed on a different idea.

This was inspired in part by a

that bathes the part in a flow of solvent, which struck me as very complicated. But I put it together with some previous experiments I'd done in mechanical smoothing, and came up with this system.

 

• Fill a small jar about 1/3 full of THF.
  
• Insert part and seal lid (I made a gasket out of a sacrificial nitrile glove).
  
• Use a rock-tumbler to ensure an even coating.
  

 

Here's https://www.dropbox.com/s/q5vkfa2ehv0pcmj/CIMG3121.jpg and https://www.dropbox.com/s/duly97d4fwuvrxo/CIMG3127.jpg pics of my first attempt, which was 5 minutes of agitation of a broken scrap part. Let me know what you think and what suggestions for improvements you might have.

Update: here's what the https://www.dropbox.com/s/uwincyw1dy48ulm/CIMG3130.jpg after another 5 minutes in the chemical jacuzzi...