DIY Blue Spotting Blues!

[graham-xrf]

The Pthalocyanine Blue Pigment + plastic bottle of Sulfonated Caster Oil from the soap-making shop, has arrived. If this works, it will be more blue spotting goo than I ever need in my life!

The passing dark thought is anyone into this soap-making thing, with the essential oils and fragrances and all, adding pthalo-blue from that shop, will definitely end up looking like a smurf!

 

[graham-xrf]

black soot mixed with linseed oil and a binder. GM formula for older wood truck beds. one of mine is done that way and is still like new 15 years later

If the carbon black worked with the way oil, it might also work with the blue stuff. OK - it still needs spirit or alcohol to wipe away, but this will be something I will try.

I am thinking the spotting goo may not be too much of a big deal. Maybe just about any colour pigment that is fine enough, and is definitely made of particles insoluble in water, can be mixed in with just about any oil that has the right thickness to spread nicely, will do.

With linseed oil, you end up with artist's paint.

 

[homebrewed]

The main thing is that the pigment particles have to be fine enough so they don't interfere with the marking process, and THEY shouldn't be abrasive, either. I'm thinking about red iron oxide, also known as rouge.

I could be overthinking this. Old hands at this probably don't worry overmuch about it if they mix up their own spotting compounds. Richard would be THE source for this kind of knowledge (and I'm glad he's around to help keep our feet on the floor, difficult as that can be at times ).

 

[graham-xrf]

I did mention that my 200ml (that's big) "XL studio" tube of ocre-rouge oil colour for artists, "pebo" brand. It does appear to be red iron oxide. Hmm - a blob of this stuff just might get put under HM-XRF someday .

It was a fraction of the price of a tube of "Micrometer" blue, and it works just the same. It wipes up with spirit or alcohol.
I know I could press on using the various oil-based goops, but I was looking for water washable Canode replacement, reasonably low cost, convenient, and the better if I could hang together a good DIY recipe at home.

I think with what I have, I have probably got all I need. The rest will be a spell of experimentation.

 

[graham-xrf]

The main thing is that the pigment particles have to be fine enough so they don't interfere with the marking process, and THEY shouldn't be abrasive, either. I'm thinking about red iron oxide, also known as rouge.

I could be overthinking this. Old hands at this probably don't worry overmuch about it if they mix up their own spotting compounds. Richard would be THE source for this kind of knowledge (and I'm glad he's around to help keep our feet on the floor, difficult as that can be at times ).

Maybe not an abrasive problem. The amount taken off in a scrape, even though about half a tenth, or a tenth would take a long time with hard going to be removed by polishing action of rouge. When I ground a telescope mirror, and got down to rouge, it seemed I could go forever without fundamentally changing the dimension. A full polishing with the rouge stage adjusts the surface by less than one or two millionths. It is because rouge cuts so slowly that cerium(IV) oxide is used instead.

The rusty red looking spotting compound we see being used in the videos has a very high probability of being iron oxide.

[EDIT: Just a heads up for anyone who gets around to messing with Pthalo-Blue. If you lose even a some milligrams onto any surface, the effort to clean it up will contaminate you, your disposable gloves, anything you touch, and anything you touch even after the cleanup. It spreads, and spreads, forever. The tips of my fingers are going blue again, maybe from keyboard keys. It does wash off skin with liquid soap and water, but only by getting ever fainter. Final stains can be picked up with plastic eraser. One hopes it sticks to and stays in sulfonated caster oil better than it sticks to most everything else].