Hello.
Yes, you can use Grey V4 mixed with remains of Grey V3.
Explained: I had the following situation. It is known, that Formlabs recommend to use standard resin tank for 2 liters of resin. As soon as i have finished first liter on Grey V3, it was impossible to buy V3 due to it’s upgrade to V4. I asked Formlabs support if i can mix V3 and V4, and they confirmed that.
- Pour remains of V3 somewhere to left resin tank out of it as much as you can. Do not use any cleaners of something like that to avoid damaging a tank. Small amount of V3 may left there. Put it back into printer.
- Insert new V4 cartridge, do not forget to check it’s injection.
- Reprogram your tank to V4. (do not remember the exact process, but there was nothing unusual there) Printer will notice you, that tank should be EMPTY.
After starting a new print, tank will be filled with huge amount of new V4 resin. As it is new and empty. That’s why you should proceed step 1 carefully to avoid any issues.
Have already printed nearly 200 ml with such mix. No problem. I print small precise items on 25 microns mostly, and bigger parts with 50 microns resolution.
Good luck