[daArch]

Although all these calcimine, casein, milk, blood paints have great properties, they become a nightmare when someone in the future wants to apply a modern day oil or latex paint on that surface.

The calcimine/casein paints were great on RAW plaster ceilings because they were dead flat, filled (actually HEALED) cracks, leveled real well, and easily maintained.

Milk paints were also FLAT and adhered very well (protein is a very strong adhesive). And the blood paints you mentioned were actually just a by-product from slaughtering farm animals.

It's great to be able to recreate historical coatings, and I applaud your inquisitiveness and research :thumbup:, but please understand we ain't living in the 18th century and some day someone is going to want to apply 21st century coatings.

I've stripped enough of ALL the above and will do all I can to discourage the use of them unless you are applying to a historical building to retain historical authenticity forever.

 

[daArch]

Arch, you saying BM Calcimime Recoater (306) doesn't live up to name?

I also think it is great he is recreating historical coatings, and think it doubly awesome he is sharing it here with us.

If anything, I want JourneymanBrian to go an extra step further and put some (306) on it to see how it reacts. If promising, then put a 21st century finish coat over the (306).

Keep going!

I too think it's great and admirable he's recreating these finishes. I wish Calcimine/casein ceilings were always kept as is. They are fabulous coatings . . . . if one don't try to PAINT over them

 

[daArch]

When I teach finishing classes for the students in the furniture program at the local university, one of the finishes that we spend a fair amount of time on is milk paint. It has a number of great attributes. It's green, it's relatively innocuous, repairable, easily top coated with oil, etc.

PS. Another finish I teach them about is soap...just soap. Clean up is a snap.

Again, it's a very durable finish, and a bane if ever needed to be stripped.

But, I'm not sure green is the only color is can be made :whistling2: :jester:

 

[daArch]

Not sure why you'd need to strip it. We've gone over it with oil primer without any issue.

can't remember WHY we stripped a banister painted with milk paint (my memory from the early 70's is a little hazed) but we did it per the HO's request. I DO remember it was one of the toughest coatings I've ever stripped.

 

[daArch]

Thanks for all the comments, guys.

As to the repainting issue, are you sure youre not confusing with distemper paint (wallpaper paste as binder)
I ask especially because someone mentioned old ceilings, which here Ive only seen with distemper paint.

Ive noticed the coat can be worn off with strong abrasion + water, but it wont chalk when rubbed with a wet finger like distemper paints do.

Supposedly this is due to the formation of water-insoluble soaps in the reaction of casein/lime.

Maybe paint thinner would dissolve the coat, I havent tried.

Another subtlety is that "milk paint" is also used to describe casein-oil tempera paint, in which the milk functions as an emulsifier of water+oil and/or resin.

I know this topic is more academic than practical, but the green painting forum is so seldomly used, I thought Id give it a bit of stimulation [emoji14]

As you allude, there can be confusion between these coatings: casein, milk paint, distemper, and calcimine.

First, calcimine is very similar to whitewash but with a glue - sometimes casein. And with use of milk protein (casein) as the glue, immediately a confusion arises between it and casein paint.

And since casein is milk protein, there exists confusion between casein paint and milk paint.

And since distemper is chalk and any number of ill defined glues . . . .

Well, I can understand how the terms are confused.

In my experience, surfaces coated with a lime (chalk) based coating need to have it washed off before an oil or waterbased paint is used.

 

[daArch]

This is our chance to prove Jack Ford correct!

http://www.painttalk.com/f2/gardz-coverstain-45170/#post834970

I'll let YOU test it out. :whistling2:

 

[daArch]

The binding agent is the key factor here:

(pure) lime paint: lime

lime/casein paint: water-insoluble glue or water-insoluble glue plus lime, depending on share of each in mixture.

casein tempera: oil (and/or resin)

distemper: wallpaper-paste (reversible, water-soluble glue)

Lime chalk (or any other anorganic pigment) can be used as pigment in all of these.
In pure lime, you dont need additional pigment, as its already white.

The blood paint works the same way as the lime/casein, substituting blood for casein.

as I said, much confusion around the world as to the definitions and ingredients. :thumbup:

 

[daArch]

A house we did back in the 70's/80's had calcimine on all wood work, previously painted woodwork. Although we never tested it, the age would indicate oil paint with lead. The calcimine was tenacious.

It's probably the only time I saw calcimine on top of a previously painted surface, and definitely the only time I ever saw calcimine on wood trim.