Resin and Calibration

Resin tools

To work with the resin, I bought a few tools. Below are the useful ones.

• Polyethlene tubing - used to siphon off salt water without removing the top layer of resin
• Fine mesh strainer - stir the vat before printing, and filter the resin after a print
• Paint scraper - removal of the object from the lift, pop bubbles, squeegee resin off lift after a print
• Diagonal snips - cut supports from a printed object 
• Latex gloves - keep the hands clean
• Isopropyl (rubbing) alcohol - cleaning resin off prints
• Polypropylene containers - sinks for the alcohol. Ziploc or Gladware work fine.

Once I had tools to clean, I loaded a vat up with water, salted it, and poured in a little resin. The resin sunk, when it should have floated. I added more salt, until I was out. The resin still sank, but slower. After some wikipedia research, I found that half of a 367g salt container was definitely not enough for 5 liters of water! I went to Home Depot for some rock salt. Since I live in a hot climate that doesn't get snow, I had to use the kind meant for water softeners, not melting ice. After putting something like 1.5 solo cups of rock salt into my already salted water, I finally saturated the water with salt. Now the resin floated!

40 pounds of flavor

I put the resin vat under the lift, and started the calibration sequence. I wrote a calibration because I don't know how long to expose the resin. I print 9 cylinders in the sequence, each with a different exposure time for each layer. At the end, I measure the height of each cylinder as well as compare their relative quality.

My first calibration sequence looked like this:

Layers floated away

I ran into a big issue: the layers didn't stick to my lift plate. In watching the resin during the dipping process, very little resin came through the holes, with most coming in a large wave from the sides. There also seems to be water spots on the top layer of resin, possibly being brought up by the lift when it dipped into the resin. However, I did find that exposing the resin about 6 seconds for a layer works well!