I had a question from a woman in a paper making group I belong to about how I got my sheets so nice and flat. The answer is easy: a restrained dryer. They are really simple to put together, and I thought I'd share pictures of the one I use at Paper Circle.
This was made with some plywood, some archival corrugated cardboard, some cotton linter blotters, and most importantly, a fan.
First you make a 3-sided box. Ours measures about 22 x 28 inside - but you can make them any size. On the back side, there should be a large hole in the middle. You stack your cardboard and blotters in this box and run the fan from behind.
When running the dryer, you want to be sure to do a couple of things. I couch my sheets on to Pellon (an interfacing) and use this to transfer my sheets from post to press to dryer. In the dryer, I sandwich these between cotton linter blotters to help absorb some of the moisture. These blotters then have the cardboard on either side. The corrugations should run perpendicular to the fan.(so that some air is being pushed through) My dryer "sandwich" goes cardboard, blotter, Pellon, blotter, cardboard. Pictured here are some sheets in the dryer:
The other thing to remember when you make a box like this is to leave a couple of inches between the cardboard and the back of the box where the fan is. This allows for air to circulate and aid in the drying. (pictured right)
A board is then placed on top with some light weights. (we use water filled jugs) The board should go all the way to the back of the box and be above the hole in the center of the back board. (we have to put in some "filler" layers of foam insulation to achieve this) This can be seen in the first picture I included.
I have also seen this same set up without the box. It is just the stacked cardboard with a weight on top and a fan behind. I'm not sure of the difference between the two. I'm guessing since the flowing air is not trapped in that space, it may take a little longer for the sheets to dry. In our dryer, it usually takes about 24 hours.
I hope this information is useful in making your own dryer. The beautiful flat sheets are well worth the work!
Happy building! And happy paper making!