Resin SIG/Equipment101
Resin Casting Equipment 101- Using the Pressure Pot and Vacuum Chamber
Pressure Pot : A pressure pot is an enclosed steel container which can be filled with compressed air to create an atmospherically pressurized environment. Traditionally, a pressure pot is used with painting equipment, but it can be modified for casting resin. Each pot has a maximum pressure rating measured in Pounds per Square Inch (PSI), and this maximum MUST never be exceeded or the pot can explode causing severe injury or death. For the Blue pot in CA, the max is 70 psi.
Vacuum Chamber : The vacuum chamber removes atmosphere within the chamber, and is mostly used to degas compounds and test for leaks. They are relatively safe unless shocked under a full vacuum (e.g. dropping a fully vacuumed chamber), at which point implosion can occur. Users should always be careful when moving a vacuum chamber under full vacuum, and if possible, should try to pull a vacuum in the location the chamber will ultimately rest. 28-29 Hg is the sweet spot for this tool.
Sizing : BEFORE using either tool, ensure that your work-piece will fit inside. In the case of pressure casting resin, make sure of a comfortable fit in the pot after it has been locked down, as it may actually feel like it fits with the lid resting on the top and then not when you go to lock it. Also verify that your container will fit comfortably in the vacuum chamber and keep it away from the vacuum pump inlet. If there is a boil over in the vacuum chamber, any liquids that spill into the valve will be pulled into the vacuum pump and damage it.
Mold usage and Leveling : Ensure a reasonable amount of overhead on any mold used in the pressure pot, and at least 2-3 inches of overhead in the vacuum chamber. When air filling the pressure pot make sure to fill with air slowly so that the airflow in the pot does not blast your resin out of the mold. A reasonable overhead on the mold will ensure that any shifting won’t cause spillage into the bottom of the pot. Note that reasonable here is proportionate to the volume of resin being used; a small jewelry mold may not do much damage but a 5x5 inch bowl blank mold will hold a considerable amount of resin. When the Vacuum chamber is used for degassing or stabilizing a large amount of air will be pulled out and can boil over out of your container and into the chamber. Keep a close eye and know you might have to lock the chamber and allow the boil to subside prior to continuing to pull a vacuum. While using the equipment please ensure it is as level as possible. Cured resin is very difficult to remove from the equipment.
Etiquette for use : The maximum usage time on either tool is 24 hours. After setting up, you must add a note to the outside of the tool with your name, phone number, date and time of when you added your project, and the date and time it can be removed. Each resin has a different curing time and removal time should be based on when the manufacturer states you can remove from a pressurized environment, NOT when the full cure will be finished. Once removed, you may move your mold and your note to the cure shelf if needed. If you are at DMS to use the pressure pot or vacuum chamber and they are in use, you are ONLY permitted to remove items from them if it is AFTER the prior users end time, as notated on their taped note. In this case, please carefully move their item to the cure shelf and tape their note to the mold. Do not disturb their resin! DO NOT remove a vacuum or pressure prior to the end time of the prior users note, this can result in ruining their project. If you come back to the equipment after your pressure time is complete, and another member is using the equipment, please check the cure shelf for your project.
Abandoned Work : After 7 days on the cure shelf, we will call the member to come remove the item. Any items left for an additional 7 days, for a total of 14 days, will be removed and sent to off-site storage.
Violations : Violations to the above requirements, damage to the equipment without notifying a CA chair or Resin SIG leader, or willful damage to another members project will result in the following disciplinary actions. The 1st offense will range, based on severity of the issue, from a verbal warning, retraining required, or a temporary ban from use of the equipment. The 2nd offense will result in removal from the AD group and retraining required, or a ban from use (temporary or permanent depending on the severity of the issue). The 3rd offense, or blatant disregard for training required and use of the equipment without having taken the safety class or being grandfathered in, will result in a permanent ban from using the equipment.
