Happy New Year, may it be a good one for all. I have been asked to share my papercrete recipe/technique. So, after a summer of experimentation, this is what works best for me.
Tear paper into about 2" square pieces. I use a combination of bond and newspaper, whatever I have on hand. In a large pail with a sealing lid, I completely cover the paper with hot to boiling water and let sit for 2 to 3 days, stirring it whenever you think about it. Boil for about ten minutes and then use a drill with a paint mixer attachment to bring the pulp to the consistency of fine oatmeal. (Great tip about sharpening the drill, thank you lava nsÂ). Place several handfuls into a dish towel and squeeze out most of the moisture. The pulp is ready to use, or can be stored in the fridge for a week or more without any problems.
Papercrete recipe (by volume):
1 pt sand
2 pt cement
4-6 pt* paper pulp
Sufficient fortifier** to produce a moist to slightly wet ÂclayÂ;
*I find a 4 pt pulp mixture is slightly easier to work with. It produces a heavier, denser, presumably stronger piece with a smoother finish.
**Fortifier: 1 pt Acrylic admix or concrete bonding admix to 4 pt water.
Note: As no hardware in Jamaica has ever heard of this material, I ended up using a local product called Ponal. It is described as a Âready for use synthetic resin glue for all types of woodworkÂ. I am still not clear what these admix products are all about, possibly someone on this forum can define them a little better and tell me if I am using the right type of product??
Mix cement and sand. Blend with paper pulp using drill and paint mixer attachment. Add enough fortifier to produce a workable clay. I prefer to keep it on the drier side and add more fortifier as I mold the clay.
I place the finished piece in full sun with a breeze, but protected from rain. Do not cover or moisten as you do with hypertufa. I let it dry for 1 to 2 days before unmolding, depending on the size of the piece and weather conditions and allow to cure for at least two weeks before applying any finish.
So far I have painted and sealed all my pieces because of the high humidity and heavy rains we experience. I have used the following colorants: acrylic craft paint, spray paint, Chinese lacquer, oil base paint (thinned), latex paint (thinned), gentian violet and even food coloring. I seal with either marine spar varnish or latex cement sealer. So far all my finished pieces are holding up very nicely, although it has been only a few months for most. I intend to try several pieces au natural to see what happens.
Here are some sites that I recommend and thank the authors of the posts. I credit them with much of the information I have presented.