Resin refers to the liquid that is used in many 3D printers, as well as the finished 3D print. It is a chemical of particular interest in shops because it, and the alcohol used to clean it, create the most serious hazards many makers will be exposed to.  The reason why shops adopt resin printing is because resin prints often have much higher resolution (fine details), survive use and storage better than FDM prints, and are less challenging to manufacture. Additional information on resin printing can be found on the Masters page.

Sections:

• Special Notes
• Risks
• Collected resin printing profiles (Future work)

Special Note on Siraya Tech Blu:

Bio-compatible resins are safe AFTER they have been printed and cleaned following the manufacturer's recommended procedures. You cannot skip steps or change the process in any way, as the liquid resin and dirty prints will still cause skin irritation. The prints only achieve their bio-compatible status after an initial rinse in alcohol, an ultrasonic bath in additional clean alcohol, a low temperature bake-out of residuals, and a 20 minute UV post cure. Instructions for proper cleaning can be found HERE. Even then, this does not make Siraya Tech Blu safe for all uses. You should not use this resin to 3D print and sell toys or use it to mold food items. This is not to imply that it would be dangerous for those uses but rather that we have no idea IF it is dangerous for those uses. The main risk of using Blu is the need to use an ultrasonic bath filled with alcohol. The Siraya Tech webpage has information on using an ultrasonic bath but does not properly prepare you for the process. It cannot be stressed enough how dangerous the process can be with only half the knowledge. If you will be going this route please read the page on Solvent Cleaning with Ultrasonics. Also, be aware that dialing in Blu may take a little longer than other resins as it is fairly temperature-sensitive. 

Special Note on Water Washable Resin:

Water washable resins are NOT safer than alcohol washable resins. Polyurethanes are hydrophobic in nature and insoluble in water. In order to make a water washable resin it must be modified in some way to make it soluble. This very often means adding diluents or modifying the resin in ways that increase the health risks associated with using it. It is also not acceptable to dispose of water used for cleaning by dumping it down the drain. Some sources have stated that water can be put out into the sun until the UV rays cause the dissolved resin to cure and precipitate at which point the contaminated water is safe to handle and throw out--HOWEVER, there is no testing to back up this conclusion. Water used to wash these parts should be taken to a waste management location for disposal. From the safety data sheet for Elegoo Water Washable: 

Resin Printing Precautions

• Fumes: Resin Printing produces fumes that need to be vented out of the house. Consider purchasing a VOC meter to check air quality in and around the machines after setup and whenever using a new resin. Grow tents made for the marijuana industry are a good solution for fumes on a budget.
• Skin Exposure: When washing parts in alcohol, use thick rubber gloves. Either dispose of the gloves after use or wear regular gloves underneath the thicker gloves to avoid contaminating the inside and subsequently exposing yourself. For handling other than washing in alcohol, a single pair of nitrile gloves is often sufficient. Secondhand exposure is commonplace around resin printers. Create a "Contaminated" area around the printer that will contain any tools used for the prints and all resin. Wear gloves when working in or with anything in this area and remove them before working in any other area to avoid cross contamination.
• Fire: Many resins must be cleaned with IPA (an alcohol). Large quantities of alcohol pose a fire hazard, thus, a fire extinguisher that covers type B should be on hand. This includes many home fire extinguishers, which are type ABC. If you have never used a fire extinguisher before, spend the $30 to buy one and try it out so you know what to expect and how to activate it. IPA fumes reach LEL (lower explosive limit where they ignite in air) at only 2%. Lack of ventilation or the use of heated IPA or an ultrasonic bath can quickly hit the LEL where the room is a fuel air bomb looking for an ignition source. In many situations where alcohol is called for, a mixture of alcohol and water below 40% or water plus a cleaning agent like simple green provides an adequate solution with less dangers.

Collected Resin Printing Profiles

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