Starch
Way back when - in the 1950's - my Mom would make a big bowl of starch that I think was Argo (navy blue and white box) starch, water, and Satina.
I am guessing the bowl held at least two gallons of starch - she dipped the item in it, wrung it out by hand or ran it through the wringer of the washing machine, and then the item was line dried.
When it was time to iron it, it was sprinkled, rolled up, and when it was evenly damp - usually the next day (if it did not go in the freezer!) , it was ironed.
It seems like dunking a large piece of fabric in a large bowl of starch would work well for large pieces of fabric - but I have not figured out what would be the equivalent of running the piece through a wringer.