Searched far and wide, bamboo forums, INBAR, Googled it to death, but still cannot find out how to make the beautiful red casien used to paint and protect bamboo in China for centuries? Anyone know?

If you google 'how to make red casien' there is a website that tells you

Copied from somewhere !!

Making Casein Emulsion and Paint

Stage 1 – Creating the Glue:

1 ounce casein powder

5 ounces distilled water (room temperature)

Stir into a container, cover it, and let sit overnight (@ 8 hours.) It turns into a stiff gel.

Water amount can vary. A very wet emulsion will cause the paint to act more like watercolor or ink.

The gel will smell like musty cheese. If it smells bitter or like vinegar (sour milk,) don’t use it.

Stage 2 – Making the Emulsion with Borax:

1 ounce borax

5 ounces distilled water

Casein glue mixture

Heat the water (not to boiling – just hot to touch,) stir Borax in water until dissolved.

Add Borax solution to Casein solution slowly and stir until it’s all combined.

Let mixture sit for @ 2-4 hours.

Pour mixture into a double boiler on low heat until it liquefies (heat to @ 140°.) See note below.*

Let it cool to room temperature and it’s ready to use.

Stage 3 – Wetting Pigment:

1 ounce pigment

Ready supply of distilled water

Caution: almost all pigment is hazardous, so handle with care. Protect yourself from inhaling it or getting into open sores. Don’t work in the kitchen, even for washing. Refer to paint-making sites for health and handling issues.

Place pigment powder in a pile on work area. Glass or marble works nicely.

Make a small hole in pile and add @ 1 teaspoon water.

Fold pigment into water. A long flat palette knife works well.

Add drops of water until you get a paste that doesn’t cake, and not too fluid.

Stage 4 – Add Emulsion to Paint:

Add small amounts of emulsion to pigment paste (not paste to emulsion,) about 1 teaspoon at a time.

Mix it together until you reach desired opacity and viscosity. Amount will vary by chosen pigment.

Test on spare paper for proper adhesion. If it’s too weak (rubs off easily when dry) add more emulsion.

If paint gets too liquid, you can thicken it by adding it to more pigment paste, or add whiting, or chalk.

Those fillers can make the paint pale when it dries.

Notes:

The casein powder can be found at various paint-making places, and “milk paint” suppliers.

 

This site shows how to make it from cottage cheese, which I’ve never bothered to do:

http://www.angelfire.com/yt/modot/painting.html

*In Stage 2, the use of double boiler heating is not absolutely necessary, but will help make the emulsion less viscous.

Raw pigment can often be rough and gritty, so invest in a mortar & pistil or glass muller for further grinding. A good source for pigment is places that supply ceramic or pottery material for glazes; although, they tend to not have vibrant colors.

Different pigments require varying amounts of emulsion to get a decent paint. There’s no standard amount that works for all, so experiment. The measurements above are approximated to give me a decent wet paint. They can vary to your own taste, especially the pigment paste Step 3.

In place of borax, ammonia can also be used, ideally ammonia hydrogen carbonate. Ammonia thins the gel somewhat and adds that odor you need to deal with. I’m investigating if trisodium phoshate (TSP) works the same, or with any drawbacks. I’ve read of certain preservatives that can be added to extend it further (formaldehyde & Dowacide A,) but I prefer not to use them, and I’d have to account for the thinning they cause.

Glycerin is a nice additive to use to increase flow and slow the drying of the paint without severely thinning it as you would with water. Use in small amounts. Tip: works with gouache too, and possibly egg tempera.

This glue is very strong and is a good substitute for PVA or hide-glue applications. The emulsion makes a good glue for gesso (whiting and pigment,) a good sizing alternative, and when diluted, coating paper to make it a little less absorbent for casein paint. It dries somewhat brittle, so keep it thin and don’t use on a flexible surface (unmounted or thin paper,) or else expect to see cracks. Remember that it is still milk, so certain pests may enjoy tasting it.

Thankyou both for your replies. I'd been searching Google with keywords like how to make ... and red casein recipes (which alarmingly threw up just one site advising the use of ox blood as the colourent:ermm:). Tad wary of the 'some pests might like it as it's made from milk', particularly as I've tried everything from house emulsion/enamel paint to ship's varnish in the past, all to no avail, but will have a go with this casein. After all, Chinese houses have stood for years using this coating.

Thanks again:)

We built a bamboo house earlier this year, so I'm very interested to hear about this paint. As it contains borax, it will have help prevent mold and bug attack, however I don't think it will be completely effective against the latter if it is only a surface coating.