This is my current process and formula for making blocks for printmaking. For very detailed blocks and engraving , the "Top Layer Calculation" below is based on the recipie for Resingrave. The Resingrave blocks that Richard Woodman made had a thicker layer of resin at about 1.5 mm. You can use this calculator by copying Google Sheet to your own Google account using the link below. The formula that Richard Woodman developed used a 4:1 type epoxy, I am using 1:1 (Hardener/Resin) here so you will need to adjust based on what you are using.
Sealer
For blocks that do not have a lot of detail the seal coat alone seems to work well for mokuhanga and western printing techniques. It also hardens the surface plus waterproofs the MDF. Here is a a video of preparing a block using just the sealer. NOTE: If you are doing the second layer with the Resingrave coating then you can skip the skim layer of fast set drywall compound.
NOTE: Recently I have first sealed the MDF with the "seal coat" in the worksheet, then sanded, filled with fast set drywall compount, sanded then sealed again with with the "seal coat". The second sealer over the filler will require about 1/3 of the calculated amount used in the initial sealing of the MDF.
Resingrave Top Layer
Materials
Sealed board from step one above.
Epoxy Resin
Titanium Dioxide
Calcium Carbonate
Magnesium Carbonate
Protective gloves
"popsicle" sticks
Containers for mixing
190 micron paint strainer
Hair pick
Weigh scale
Leveling table or shims
Process ( Casting the Resingrave layer)
Sand the "sealer" layer and wipe clean.
Build a dam around the perimeter of the board using masking tape and burnish to prevent the resin from leaking out.
Level the board with shims or a leveling table.
Filter the powders with the 190 micron cone filters.
Measure out the B part (hardner) and add the powders and mix well. Heat in microwave in short bursts, I wend to 115 F and continue mixing until well mixed.
Measure out the A part (resing) and add to the mixed B part and powders. MIx well usually 2 minutes.
Heat the mixture back to 115 F to lower the viscosity.
Pour through a 190 micron cone filter on to the block.
Spread out the epoxy using the popsicle sticks and the hairpick.
After you have the surface coated and leveled a quick blast with a propane torch or heat gun will help reduce the bubbles from mixing.
Let set. The resin I have been using takes at least 12 hours.
Process (flattening and sanding)