Monday, December 1, 2014

cold acetone fuming

I posted a video on cold acetone fuming several weeks ago, but I thought some people might like to see the results of this fuming process. In teaching courses on 3D printing, I find that students will try anything that they find on the internet (regardless of possible dangers), so I thought it best to discuss cold acetone fuming as a way of warding off any disasters from heating acetone. Honestly, I am not a fan of how the fumed parts look, but I have to admit that the strength of the parts does make it a process worth doing on functional non dimensional parts.

Here is a part that has had the supports removed and just a bit of filing done to the inside surfaces where the supports were. The outside top section shows striations due to the angled position as it was oriented on the print bed.

For cold acetone fuming you will need an airtight acetone resistant container, some acetone, aluminum foil, and some paper towels.

I make a bottom liner out of aluminum foil so that it lines the bottom of the bucket. This will prevent the 3D printed part from sticking to your container. At this point make sure that your printed part will fit inside the container without touching the sides, etc.

I then dampen the paper towels with acetone (making sure that they are not dripping with acetone). I drape the towels over the side of the bucket and again make sure not to get any acetone droplets onto the 3D printed part.

Seal the container by placing the lid.

It may be necessary to re dampen the paper towels with acetone over the course of the fuming period. I let this particular part fume for a full workday so I ended up reapplying acetone twice since my lid did not seal well the first time I closed the bucket. Once I was pleased with the surface, I removed the print by lifting out the entire aluminum foil liner. The print will be very sticky at this point, so you need to allow time for the print to re-soildify and off gas. Be patient!

After a few hours you should be able to pick the part up and complete assembly as needed. You may notice that the striations on the sides of the part are gone. The top surface will still show the layering of the print regardless of time. Keep in mind that you could use a vibratory tumbler or rotational tumbler with abrasive media if you were looking for a less shiny surface. I have also experimented with a sandblasting cabinet with various media. Using baking soda as a blast media leaves a nice satin finish that many of you may like.

Caution: please make sure to use acetone resistant gloves when handling the acetone and paper towels. A respirator and well ventilated area is recommended. I like to leave my sealed cold vapor bath container in a ventilated spray booth. Exposure to acetone should be taken very seriously and necessary safety precautions are advised.


raster said...

Nice! I've not seen the cold method before, but it does seem easier (and safer) than the hot method, as long as you don't mind how long it takes. I'll have to give this a try, once I get my printer printing again. :/

Frankie Flood said...

Yes! Much better tan heating acetone.