SoliForum - 3D Printing Community — Yet another smoothing station

Re: Yet another smoothing station

null@example.com (IanJohnson) — Mon, 04 Mar 2013 17:46:44 +0000

Someone posted a stirrer on Thingiverse that they made by using a fan to spin the magnet under the vessel. If you have a strong enough magnet you should be able to spin another fan with a magnet glued to it inside the jar. You wouldn't need much airflow, you just need a little movement to get the acetone up off of the bottom.

http://www.thingiverse.com/thing:42445

Stirring the acetone itself might help throw off a little more vapor as well.

Re: Yet another smoothing station

null@example.com (lotw_1) — Mon, 04 Mar 2013 16:27:05 +0000

I like the setup, but I would use a solar panel for powering the fan, if possible. Good way to just set outside without needing a power source or batteries.

Re: Yet another smoothing station

null@example.com (tealvince) — Mon, 04 Mar 2013 16:22:54 +0000

Looks like a squirrel torture device!

If the fan is brushless, I think it would be okay, but I'd get the lowest voltage fan possible just in case. I can't imagine a 3V brushless fan would pose much risk. As an alternative to suspending the fan inside, I'm curious if anybody has thought of using one of those magnetic stirrers they have in labs (or rigging up an equivalent)?

Also, about avoiding sealed containers, since my acetone came in a sealed container (albeit with a narrow neck), how much pressure are we talking about here? It's been years since I had to do this type of calculation, but the vapor pressure of acetone is 230mm-Hg at 25 deg C, which is about 5psi, I think. For that, it seems like a small stovetop pressure cooker would suffice if you used it just as a vessel at room temperature, since they normally run at 15psi above atmospheric pressure. Then you could use it (more) safely indoors and wouldn't waste acetone by evaporation. Crazy idea?

Re: Yet another smoothing station

null@example.com (Kvirre) — Mon, 04 Mar 2013 13:55:41 +0000

Since I used it outdoors for safety reason, (-1 C) in Sweden, It took much longer time than needed (about 6 h)
(Based on the fact that boiled acetone-vapor smooths in less then 1 minute, it's safe to assume it's temperature-dependent)

From what I read-up on from others experiments, 4 hours in room-temperature should do it.

Re: Yet another smoothing station

null@example.com (Zarni) — Mon, 04 Mar 2013 13:02:49 +0000

I guess it comes down to the type of plastic that the fan is made of.
If you had a metal lid you could make up a simple fan blade from a bit of tin can and have the motor on the outside.

When you say wait.........for how long? A minute, an hour, a week?

Re: Yet another smoothing station

null@example.com (Kvirre) — Mon, 04 Mar 2013 12:29:07 +0000

I ran it for 6 hours straight, no problem so far.

Re: Yet another smoothing station

null@example.com (Gordym) — Mon, 04 Mar 2013 11:58:28 +0000

I considered adding a fan to my smoothing station but was concerned that the acetone might attack the plastics in the fan.

Yet another smoothing station

null@example.com (Kvirre) — Mon, 04 Mar 2013 11:27:40 +0000

I took the experiment someone did with the paint-bucket and acetone and made another version.
Since Acetone-Vapor is heavier than air, I tried to stir the air around using a fan.

No heating, just wait.

WARNING

- The cigarette was there just to study airflow (no acetone obviously used at this step)
- After adding the acetone and removing the cig. this fan could "possibly" ignite the fumes?
- Don't use a tightly sealed container, I only had the lid resting on top, and not stripped down!

Be careful, I would be upset if somebody got hurt ...