Thank you all!!!
My plastisol has heat stabilizer and I have used more to add to the reheatings… but I didn’t feel it helped much… anyway, I can keep yellowing under some control slowing down the reheats and adding raw plastisol…
I am visiting the US so I planned to take the presto back with me in the baggage, but I will finally go with the vacuum chamber, specially due to the power supply we have in my country (230v and 50hz), because you can’t find presto pots out the US…
So I will go with the chamber while I figure out how to build a similar system with european stuff!
Thank you again for your help!!!!!