Allows Visual Monitoring of Degassing and Casting Operations
See What’s Going On Inside Under Pressure or Vacuum
Right or wrong, and subject to controversy, these are the general steps that can help produce bubble-free parts or molds using resin or silicone rubber:
- Measure out the two parts of the casting/molding material
- Mix any pigments or additives with one part of the resin or rubber, usually recommended by the manufacturer
- Optionally degas the components now – before combining – to minimize entrapped air or moisture. Do not over-pump below material’s vapor pressure, or you will create a nearly endless supply of new bubbles..
- Prepare to work quickly once the materials are mixed in the next step. The clock will be ticking…
- Thoroughly mix the two parts together, stirring and scraping the side walls. Transfer the mix to a new container if desired to minimize unmixed pockets of material.
- Fast-cure resins or mold rubbers may not give you time for this step, but degassing the mixture in a vacuum for a short time will help remove air entrapped in the stirring process.
- Remove the degassed mixture and carefully pour around part or into mold.
- Again, and only if time permits, quickly degas the the resin/mold or the mold-material/pattern to boil off bubbles introduced during the pour
- Apply 45 – 60 psi pressure to the casting chamber for the duration of the material’s cure time.