10%: 45 mL vaseline, 5 mL mineral oil
15%: 50 mL vaseline, 7.5 mL mineral oil (for better accuracy: 68mL Vaseline and 12mL mineral oil - LH)
- Add Vaseline to a 100ml beaker and heat until liquefied on a heating plate. Add more as necessary.
- Add mineral oil.
- Mix to combine well with a spatula.
- Label syringes (10% or 15%) with label tape. (Remove needles if not already removed.)
- Keep the heat on, and while the mixture is still warm, submerge the tip of the syringe and pull the plunger SLOWLY to collect the Vaseline mixture. (Fill the syringes up to the desired level, usually ~6-8mL.)
- Wipe the tip of the syringe with a Kimwipe.
- Flip the syringe and push the plunger to push out the largest air bubble. Try not to push out the Vaseline itself, as when it accumulates at the top, it becomes hard to attach the needle onto the syringe tip.
- Leave a sticky note with your name and the date the syringes were made.
- Allow to cool down and solidify VERTICALLY for at least 1 day (this allows bubbles to accumulate either at the top or bottom and not in the middle or along one side of the syringe.)
- Once solidified, place into the container on the dissection bench.
To bend the needle tip, use wire cutters to cut off the sharp part of the syringe tip, then use pliers to open the tip (press on the ends of the tip that were squished by the wire cutter) and bend the tip about halfway up to the desired angle. Opening the tip is more important for the lower %s as the formula becomes harder to push out of the syringe.
Tweak the ratio of mineral oil to Vaseline to for desired consistency. Lower ratios will be harder to push out of the syringe, higher ratios will be easier.