Difference between "paint" and "Jappaning"

[scott spencer]

Can anyone of you point me to the difference between paint and Jappaning? As I look to restore the Bedrock 605 (http://sawmillcreek.org/showthread.php?t=105057) I posted about last month, I'd prefer to do it right if it's feasible.

Thanks!

[David Keller NC]

Scott - "Japanning", at least in the old-school formulations, is asphaltum and lamp black in a linseed oil carrier. Theoretically, it could also be called "paint", because old paint formulations for black were often lamp black, linseed oil, and white lead (lead II oxide).

However, the difference is in the method it was applied and cured - Stanley applied the coating in a thick, single coat, and then the casting was baked to drive off the linseed oil, polymerize what didn't vaporize, and to "set" the coating. Incidentally, the historical practice as I understand it also included the annealing of the raw grey iron casting - the japanning and annealing were all done in one step.

Afterwards, the casting was machined to its final surface.

Paint, of course, is designed to cure without the requirement of firing, and so it contained a higher fraction of metallic driers - this was white lead before the 1970's, and salts of cobalt thereafter.

From the standpoint of restoration, Derek Cohen's published his experiences with a product that's designed to look like japanning, and I believe contains the same asphaltum, but will cure at room temperature over a couple of weeks. You might check out his website for additional info.

[scott spencer]

Excellent and useful response David! Do I detect "Chemistese" in your accept?! ;)

Thank you.

[David Keller NC]

Yeah, I'm a chemical engineer (PhD). I've an interest in old paints and finishes (though typically from the 18th century). The only problem with reproducing a lot of these old formulations is that some of the components are quite toxic or potentially dangerous. For example, the original laquer formulations that Stanley came up with for finishing their rules and levels requires the manufacture of gun cotton (nitrocellulose) as a step in the process -not exactly a safe endeavor!

[scott spencer]

Having worked with several great chemists and chemical engineers at Kodak over the years (many of them PhDs), your descriptions definitely conjured up memories of their discussions. I sure do miss some of them.

[Matt Z Wilson]

And some people wonder why old scientists were "mad". Back when I was in the lab, we did a lot of inorganic chemistry with transition metal complexes (like iron, manganese, and nickel). My PI was interested in cyanide compounds. One of our syntheses involved dinitro-toluene, which is just a little different than TNT. We joked that if he ever had a bad day then a whole lot of people were in trouble.

[Jerome Hanby]

You can order Asphaultium (sp) from some Art Supply sellers. I found several good articles on Japanning by googling. I picked up a toaster oven off of Freecycle since I figure my wife would kill me if she found me baking plane bodies in the kitchen. Also picked up some washing soda and rebar. So, one of these days I'm going to put on my mad scientist hat and electrolosize away the rust and re-japan some of these old planes I bough off the bay.

[Berl Mendenhall]

Thank you David. I had wondered what Japaning really was but just never looked it up. Very informative. Now I know.
Berl

[David Keller NC]

Jerome - If you don't want to fool with the electrolytic method for rust removal (admittedly, it's messy and potentially dangerous), citric acid works really, really well is dirt cheap to boot. Its advantage over acetic acid (vinegar) is that it has nowhere near the amount of bad smell, and acetic will eventually attack iron if left in too concentrated a solution or for long periods (days). You can get citric at home brewery supply sellers or at some pharmacies.

Evaporust apparently works very well too, as reported by some of the forum members. I haven't tried it - it costs too much and citric works too well.

[Casey Gooding]

FWIW, Semi-Gloss Rustoleum looks almost the same. Easier to apply.

[Stephen Shepherd]

I have found a good mixture of 50% asphaltum (quality roof tar) and 50% McCloskey's Marine Varnish (gloss).

It will dry in a few hours depending on temperature and humidity and cures over the course of a couple of weeks. This mixture remains somewhat flexible and doesn't require an oven to cure.

Stephen

[Jerome Hanby]

Probably says something about me, the messy and potentially dangerous part is what I like about the idea :D

Thanks or the citric acid tip!


Jerome - If you don't want to fool with the electrolytic method for rust removal (admittedly, it's messy and potentially dangerous), citric acid works really, really well is dirt cheap to boot. Its advantage over acetic acid (vinegar) is that it has nowhere near the amount of bad smell, and acetic will eventually attack iron if left in too concentrated a solution or for long periods (days). You can get citric at home brewery supply sellers or at some pharmacies.

Evaporust apparently works very well too, as reported by some of the forum members. I haven't tried it - it costs too much and citric works too well.

[Justin Green]

How long do you keep citric acid around once mixed up? Will it "keep"?

[Mike Brady]

I mix one cup of dry powder to a gallon of hot water for derusting. Any unused dilute citric acid will keep for a very long time. It turns a pale yellow color, but remains just as effective. I would't keep used stuff.
This is my 605 after restoration and repainting:http://i234.photobucket.com/albums/ee300/finefettle/MWTCA004.jpg