Make:

This is a follow up to my previous thread on using dextrin to coat the paper for a 100% toner transfer to the PCB. In that discussion we found that some application methods work better than others with most leaving a heavy curl on the paper or a lot of warping. Here is one that produces an undistorted sheet of paper, except for perhaps a very slight curl, but not enough to cause feeding problems:

Materials: Kiwi Camp Dry spray (says 13% silicone), dextrin solution as thick as you can make it by reducing over burner, glossy laser paper like Staples brand or other, rubber roller, and a clean Teflon cookie sheet.

In the cookie sheet, place a sheet of paper, spray with silicone. Saturate it good on both sides. The paper should be translucent without any spots missed. Squeegee out all you can with the roller, flip and do it again.

Use a paper towel to wipe down the sheet so as to remove any excess silicone on either side. Set aside to dry - the paper will look about normal when the drying is complete and will have no wrinkling or warping whatsoever. Do this for however many sheets you will be making in the batch.

Clean the tray with soapy water and dry throughly.

Drop in a dried piece of paper from the first step and sprinkle a few drops of dextrin solution on the top side. Use a rubber roller and lots of downward pressure to spread the solution evenly over the surface. Keep rolling it until it begins to feel tacky, but not so sticky that the roller peals it up off the tray. Let the sheet sit in the tray for a few seconds (not longer or it will stick to the tray) and remove to dry somewhere. It will be dry to the touch within a few seconds, but should not be used for at least 10-15 min.

Print your board design on the dextrin side and fuse this to your PCB using an iron or laminator. You will need to use soapy water to release the dextrin from the paper because of the silicone resisting water penetration. When the paper is translucent from the soapy water it should slide off on its own and 100% of the toner will be transferred to the PCB.

It sounds like a long process, but it really does go quickly after the first few sheets.

Possible improvements:
Use of something other than silicone spray. Deck sealer by the gallon?