Re: Home made Paint
I made some paint a few weeks ago.
I didn't quite get enough drier into it, working without a scale, but it is slowly, very slowly, polymerizing. I'll have another bash at it soon when I get some time.
You can make effective white paint with Sunflower oil. In fact, many of the better quality oil based paints use sunflower.
Paint making is actually a quite simple process and for artwork it's even simpler, because you don't really care if it lasts in the marine environment.
You need different ratios of driers for different oil bases.
Sunflower is a semi-drying oil and so definitely needs some driers. I tried to use Cobalt acetylacetonate at about 0.05% + Zn acetylacetonate at about 1.5% but I didn't get the measuring right as stated above.
Cobalt is a surface drying drier and too much will cause wrinkling, while the Zn drier helps to dry right through the paint layer and serves to control the wrinkling a bit.
Titanium dioxide is the white pigment that almost all paints use, whether they are coloured or not. Good quality paint is about 27% by weight TiO2, and the pigments for specific colours are usually added on top of this. TiO2 is about 800 USD per ton. Artists paint are usually higher in solids to make them stiff.
If you want a gloss paint you will need to include a resin of some sort. I just bought a 100g bag of gomma (refined) from an Italian place. It cost 6 euros. the amount to use is determined by trial and error - make a few small batches. Melt it into the oil base and mix everything up from there. The resin will make it shiny and also harder and more durable. If you want to prctice a little you should be able to come up with adequate paint quite easily. Alkyd resins in most modern paint are made using food oils as raw ingredients. The process is a little complicated for home use. Any good quality hard resin can be used instead, Eg, shellac, or kauri gum (not easily available now...).
The Oil should ideally be de-waxed first, and there are processes to do this. Some involve treating with a little acid, and also boiling. and removing the precipitated waxes. (also something about soaps in there but I can't remember exactly.)
Linseed is a drying Oil meaning it will dry (eventually) without driers. Ting oil also but it dries faster. You can include these in paints to change the properties of the drying.
Solvents (mineral turpentine etc) help to keep the paint flowing at the correct consistency and the evaporation of these is the first part of the paint drying process.
For art work it's definitely worth making your own.
For boat work, you can, if you need lots of paint and you know what you're doing, make perfectly adequate to quite good paint, for less than you'd pay for it.
If you know someone at a university you can probably get the drier chemicals through them. Also, if you can use a zirconium compound instead of the cobalt you take the minimal risk even lower. Cobalt is not especially toxic, and Zinc and Zirconium are almost non-toxic. The oils are food oils, and TiO2 is often added to food...
Mineral turpentine is, well, mineral turpentine.
Si Dieu n'existait pas, il faudrait l'inventer -- Voltaire