Here’s one approach to making injection-port lids which I quite like:
- RTV silicone (high-temperature)
- Micropore tape
- Drill two holes in the lid (filter hole slightly larger than injection-port hole)
- Apply a small blob of silicone to one of the holes and swirl it around
- Strong smell from the silicone: work in a well-ventilated space
- Add a second blob of silicone to the same hole on the other side of the lid
- Try to ensure there are no air bubbles between the two blobs of silicone
- Set the lids aside so the silicone can set (24-48 hours)
- Cut Tyvek squares and tape one over the second hole (with micropore tape)
The Tyvek in this case comes from USPS mailing sleeves. I’m not sure if it’s still the case, but you used to be able to get these for free at some USPS mail boxes. I have also found Tyvek locally in the form of reusable shopping bags.
Another approach is to cut a square of Tvyek roughly 1.5 - 2 times the diameter of the mouth of the jar. Fill the jar with grain / liquid culture, place the Tyvek square over the jar opening, then screw the lid on over the Tyvek. One hole has the injection port, the other is covered with a layer of micropore tape. When injecting LC into the jar, pierce the injection port and the Tyvek filter.
Feel free to share your preferred lid-prep techniques here! It’s nice to have a range of different techniques to employ when certain materials or resources aren’t available.