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August 6, 2023 at 5:28 pm #1521937
Hi All
Im a hobby oil painter from Australia. I paint all types of subjects in an attempted loose style mostly inspired by artists such as Sorolla, Sargent, Zorn and Monet.
Im planning to make my own lead white (LW) using the stack process and I would greatly appreciate your advice on some questions regarding its production.
1 My Aim
I would be extremely happy if I could produce a paint similar to the opacity and “body” of what commercial flake white used to be.
(Also I would like to thank the people who were very kind and generous to openly share their knowledge and experience on the subject of making LW.)
2 The Temperatures/ Season
Ive read everything I could find on the subject and came across a statement in one of the articles that the lead white produced was too transparent ..but there was no explanation why.
I assume that it is likely to be caused by the flake crystals growing too large and that this may be a consequence of the temperatures that the process had occurred in (assuming that the lead acetate was adequately washed out of the basic lead carbonate).
So I would like to ask the people who have successfully made their LW what temperatures or season did they make stack process LW in?
3 The Oil
I intend to make my paint using cold pressed, alcohol refined, sun thickened (40 days in mild summer sun), linseed oil.
Im unclear though, if the oil should be made as thick/viscous as possible to produce a thicker paint or if a less viscous oil is required to achieve a thicker paint?
4 The Grinding
From what Ive seen, the LW dries into a fairly solid cake (biscuit). Im wondering if anyone has thought of as SAFE method (without lead being released into the air) to break the biscuit up so that it can be mulled. Im thinking of to break it up while in a plastic bag with a hammer or driving the car over it?
Also do I need to mull with water first for an half hour before mulling with oil?
5 Tube life
What sort of tube life are people getting once they have stored their LW paint in tubes (Aluminum Stearate is difficult to get)?
Im sorry if Ive burdened you with too many questions!!
August 6, 2023 at 6:51 pm #15219494 The Grinding From what Ive seen, the LW dries into a fairly solid cake (biscuit). Im wondering if anyone has thought of as SAFE method (without lead being released into the air) to break the biscuit up so that it can be mulled. Im thinking of to break it up while in a plastic bag with a hammer or driving the car over it? Also do I need to mull with water first for an half hour before mulling with oil? 5 Tube life What sort of tube life are people getting once they have stored their LW paint in tubes (Aluminum Stearate is difficult to get)? Im sorry if Ive burdened you with too many questions!!
Breaking up a biscuit? When the coils of sheet lead are fully corroded, they become friable and crumbly. You certainly don’t have to hammer them or drive a car over them. If there’s still some uncorroded lead sheet there, you haven’t let the corrosion go far enough.
Did you read this guy’s white lead making and washing technique?
https://www.harrysteen.com/stack%20lead.htm
Aluminum Stearate tends to react with white lead pigment and paint gradually hardens in the tube. That’s why companies like Old Holland and Williamsburg use a little Castor Wax melted in the grinding oil to stabilize their white lead paints. White Lead in oil without stabilizer can start to separate and the pigment portion can stiffen in the tube within a year, particularly if you have hot summers. Freezing the tubed paint greatly prolongs the softness in the tube. Natural Pigments’ Rublev oil paints are claimed to have no stabilizers. But they add a small proportion of bodied standoil to the normal, thin grinding oil to act as a suspension agent,
August 6, 2023 at 10:25 pm #1521958Thank you for your reply Antonin.
I have read all the articles you have mentioned. thank you.
By Breaking up a biscuit with hammer I meant, after washing, the lead flake is left to dry. Once dry, it appears to become like a fairly hard “biscuit” or a lump of consolidated lead flake that has to be broken into small mullable pieces .
The videos Ive seen required a knife to break up the dry lead “biscuit”. Im thinking that during that breaking-up process, there is potential for fine lead flake to get released into the working area (eg inside my shed) thereby contaminating it. I did observe that the small pieces are crumbly
Antonin, thanks for the Castor Wax idea, is there any further detail on this? ie percentage by weight that should be added to the grinding oil? I guess you would heat the wax in the grinding oil and heat until wax is dissolved, then use it for the mulling process?
August 7, 2023 at 12:58 am #1521965Thank you for your reply Antonin. I have read all the articles you have mentioned. thank you. By Breaking up a biscuit with hammer I meant, after washing, the lead flake is left to dry. Once dry, it appears to become like a fairly hard “biscuit” or a lump of consolidated lead flake that has to be broken into small mullable pieces . The videos Ive seen required a knife to break up the dry lead “biscuit”. Im thinking that during that breaking-up process, there is potential for fine lead flake to get released into the working area (eg inside my shed) thereby contaminating it. I did observe that the small pieces are crumbly Antonin, thanks for the Castor Wax idea, is there any further detail on this? ie percentage by weight that should be added to the grinding oil? I guess you would heat the wax in the grinding oil and heat until wax is dissolved, then use it for the mulling process?
From the above linked White Lead article:
“Let the water in the Pyrex dish settle, then carefully pour off as much as possible. Put the dish on the hotplate to dry out. If you’re worried about dust, put a piece of glass on top, propped up at an angle on scraps of 1×2 or something. It will cover the dish, but the water condensing on it will run down off the low edge, rather than dripping back into the lead white.
Leave it overnight. To make sure it’s dry, watch for it to stop steaming, then give it a few hours more. The dry lead white will have big cracks running through it like dried mud.
Put on a respirator. Loosen the pigment from the bottom with a spatula or painting knife or something, then spoon it all into a 16 fl.oz jar. Don’t worry that it’s in caked lumps rather than a fine powder; it may even be easier to deal with that way.”
Either break it up outside with a real Respirator, surgical gloves and $10 overalls that you take off outside:
Or make a dust-proof box (out of a transparent storage box). Cut 2 holes large enough for your arms, into 2 of the rounded corners. Be sure there’s a large enough area in the center so you can view what you’re doing with the pigment.
Get some very long rubber gloves (make sure they’re long enough to give you mobility inside the box and to also extend 7″ or 8″outside) and tape them into the storage box (at the appropriate depth) with wide vinyl duct tape; sealing them air-tight without gaps; you don’t want dust escaping.
Then place the Pyrex dish with the chunk of white lead into the clear box with a large SS paint scraper or SS spatula, plus a storage container for the finished broken-down white lead clumps. Think of whatever you’ll need inside the box beforehand, because you’ll seal the lid to the box with more duct tape. You don’t want movement inside the box to allow dust to escape from whatever tiny gap there might be between the box and lid.
When you go to grind it, put on your respirator and surgical gloves. As he says don’t worry if the finished white lead is in caked lumps. Pour some oil over a little pile of White Lead pigment that you’ve placed in the center of your ground plate glass. Take the wide SS paint scraper and use a little gentle up-and-down chopping motion to break up any major lumps. Then place a 4″ glass muller over the pigment pile and start grinding. Be sure to clean up your working area scrupulously after you’ve finished,
August 7, 2023 at 3:33 am #1521971Thanks for your reply Antonin.
Could I inquire if you have made LW paint yourself?
In what weather did you undertake the process?
What paint consistency did you achieve?
Castor Wax idea, is there any further detail on this? ie percentage by weight that should be added to the grinding oil? I guess you would heat the wax in the grinding oil until wax is dissolved, then use it for the mulling process?
I am thinking of a similar sort of “isolation box” setup like you suggest for the mulling process!
Also, I intended to dry the LW flake in the sun.
Harry Steen also mentions the Stack process be done in the summer, but Ive seen much evidence of others that have undertaken the process during autumn and spring temperatures.
Also they do not describe any additional post processing with vinegar as harry does: viz:
” Then fill the jar with vinegar and cap it up. Leave it for a few weeks, stirring it every day. The vinegar will gradually dissolve the small flakes into a fine pigment”
I wonder if these two factors are the cause of the enamel like paint properties which I dont want viz:
” This stack process lead, however, doesn’t work as well; it has a much greater tendency to be enamel-like”
The consistency of LW paint that Oscar Econome and Luis Borrero demonstrate in their videos seems good and not enamel like.
August 7, 2023 at 5:16 am #1521992This is from Natural Pigments website regarding the variety of Castor Wax called Thixcin R (there may be some performance difference depending on the degree of hydrogenation the oil is subjected to):
“Castor Wax is a non-hygroscopic organic derivative of castor oil. Use as a rheology additive in oil and alkyd paint, to add thixotropic body and prevent oil separation. Does not react with pigments and vehicles and does not detract from the durability of paint. Assists in the stabilization of water-in-oil emulsions. Add 1–2% of total pigment weight.
Castor wax is primarily used as a rheological additive to add thixotropic body and increase viscosity, reduce settling of pigments and extenders, control sag without impairing flow to produce optimum leveling in paints, control liquid penetration into porous surfaces and has no adverse effect on durability and lightfastness and is non-yellowing.
How to Use
The optimum use level of castor wax varies depending on the vehicle and on the desired degree of thickening. A typical starting use level is 0.2% to 0.8% by weight of the total paint. Castor wax should be added to the vehicle before grinding with the pigment, preferably by mixing in the vehicle for about five minutes before other components are added. When incorporating castor wax a lower and an upper processing temperature must be observed. A minimum temperature of about 43° C (110° F) is necessary to build the thixotropic structure properly. If a 55° C (130° F) temperature is exceeded, soft gel-like particles may appear on return to room temperature. The presence of aromatic solvents lowers this upper temperature limit. Should this limit be exceeded, the formation of particles can be prevented by continuous stirring during cooling to 45° C (113° F) or below. Within the prescribed temperature range, castor wax should be subjected to as much stirring as possible during processing. The more intense the stirring or grinding action, the more pronounced and immediate is the effect.”https://www.naturalpigments.com/mediums-grounds/resins-gums-waxes/castor-wax.html
I haven’t made stack flake white. I’ve been tempted to over the years, but didn’t have the time – when I was tempted.
I’ve ground commercial flake white a number of times. Initially they were the superior flake whites that were made in the US.
The more recent lead whites are all from China and they tend to be very finely divided, kind of fluffy and characterless.
_____________________________-
You’re referring to “It’s extremely stringy and thixotropic, and produces dense, opaque layers even when quite liquid. When you use it, you quite often find yourself getting little flashes of realization of why certain details in old paintings look the way they do.”
Would you rather treat it with vinegar for smaller flakes or first “grind with water on a glass or stone slab. This makes your lead white powder very fine or textured. 1/2 hour for rough grind or 4 hours for German painting.” like Borrero mentions for Pacheco?
The vinegar treatment may be why Steen’s washed and dried white lead is easily broken up. He’s not using a hammer or driving over it. Maybe you could shorten the vinegar treatment for less finely divided white lead? I like his Pyrex dish idea – the pigment wouldn’t stick to the shiny glass and it wouldn’t scar up like plastic does.
Borrero’s example of finished paint looks pretty stringy – what would be called long paint:
Aren’t you going to add a wax stabilizer anyway? That should take care of any tendency to flow. You could also add a little fumed silica mixed in oil to the paint on the palette as you’re painting. That would also firm up the paint texture.
The readymade oil paints from the time of Sorolla, Sargent and Monet were stabilized with beeswax, Champaign chalk and/or animal fats.
Rembrandt’s whites often had a tiny amount of egg yolk added – try it – it’s surprisingly effective for crisp paint. Just mix in a dried lentil-sized portion to 3/4″ of paint (with a palette knife), when you’re ready to paint.
Look up Osamu Obi. He uses a mayonnaise-like medium of sun-thickened oil, egg yolk with a small amount of vinegar to keep the medium fresh and stable longer. These egg mediums are not used with water – turpentine or odorless thinner are used if thinning is required.
August 13, 2023 at 3:23 am #1522590Hi Antonin
Sorry I didn’t get notified of your response!
The two main issues Im concerned about regarding the paint are, opacity and getting a stiff buttery consistency.
From Borrero’s info, when he ground it for 4 hours it makes the paint enamel like as used in German paintings…So the more its ground the more liquid and therefor less “buttery” it becomes. So if I don’t water grind…it should be at its most “bulky” consistency?
Oscar Econome, advises not to agitate the LW too much even during the stage where its wet just after being washed so as to leave the large particles in tact. He also advises not to grind it from a safety point of view as well. The consistency of his paint appears very similar to Borrero and Steen. So maybe the additional water grinding and vinegar processing are not necessary for what I want.
Thanks to your suggestion, the use of wax may improve the stiffness and tube storage problem in one hit!
Im wondering if Bees wax is better than Castor Wax ?
May I ask if you have had personal experience with the use of either wax and its effect on LW?
How long has the wax kept your LW in suspension?
did you get a buttery stiffness?
Also on the issue of breaking up the LW cake, the caked lumps of LW will need to be broken up into smaller Mull-able pieces. It will be much easier and neater to breakup the cakes in a plastic bag with a hammer (or the car) than inside the “isolation box” where movement will be limited. Borrero showed how his pile of LW was already broken down into small “granular clumps” prior to his water mulling. He did not break-down the cake using the Muller, probably because larger un-crushed cake pieces are too hard to compress with the Muller.
Anyhow, I think this is the type of question that can only be answered by experience.
PS: Not really interested in using Egg whites and such at this stage. Thanks for the suggestion though.
Regards
October 2, 2023 at 1:15 pm #1527908I have made stack process lead white. It is no pun intended a piece of cake. A bit of hard work but not difficult. I yielded 2 kg of purified pigment and split it into 50g plastic containers left over from spices, herbs.
I use it with sun thickened linseed oil and I use a heated oil based on linseed with litharge, black oil namely.
When ground and applied it has a beautiful, pearlescent quality.
October 2, 2023 at 1:21 pm #1527909October 2, 2023 at 4:32 pm #1527934Hi Quiggsy
Thanks for your reply.
Great Pun!
Your LW powder looks great!
- In order to Mull the LW with oil more safely, I’m now thinking it may be feasible to store the washed LW in its “slurry” form (after washing it) in a sealed plastic jar under about an inch of water. By doing this, I avoid its most dangerous form which is when its in powder?
- Do you post process the LW in any way before mulling it ie, like storing it in vinegar for a month?
- I’m now thinking of using cold pressed flax seed oil (that Ive removed the mucilage from) which is sun bleached and slightly pump thickened over 10 days using the CSO method. Id rather not make litharge.
- Does a thicker oil make a thicker paint?
I would be grateful of any comments you may have.
October 5, 2023 at 9:26 pm #1528208Lead white is beautifull…
A friend came by just when I was washing the corroded lead coils, I put out my gloves, and with bare hands I showed him a coiled lead roll out of the box and explaining what I was doing.
My hands where milky white from the lead water, after 10 minutes talking I went inside to wash my hands.
Next day we went for a holliday and early in the morning about 4.00 I wake up feeling very sick, I decide not to wake anyone and to took a run to feel better. During that run I started trowing up, my head was exploding, for ours, and get very very ill, keep this story short, I came in a hospital ‘with lead poisoning’ and almost was gone.
I dont believe the stories that it does not come trought the skin or whatever, we don t know exactly how it came in my blood. After five years there are days I am still not the same.
October 5, 2023 at 11:45 pm #1528227Lead carbonate is mostly safe at the skin barrier, but if I recall correctly lead acetate isn’t. So no, handling bare corroded lead coils or the wash water from them is definitely not recommended.
insert pithy comment here.
October 6, 2023 at 2:20 am #1528241Titanwhite, I’m very sorry to hear what happened. I hope you fully recover soon. Thank you very much for sharing your very unfortunate experience a scary warning!…some on the internet seem so casual about handling this stuff!
Marc Kingsland, thanks for the clarification. Yes, Ive read somewhere that even breathing the Lead acetate vapor is dangerous!!!
So Ill let the the vapors release into open air before getting anything out of the dug heap!
This stuff IS deadly!!!! Sounds like Im right in trying to be very cautious.
Has anyone mulled it in its in its watery “slurry” form?
October 6, 2023 at 11:30 am #1528288Has anyone mulled it in its in its watery “slurry” form?
I haven’t tried this myself, but it was occasionally done historically. The lead white prefers to be bonded to oil so it will gladly cast off the water as it’s mulled. Unknowns to me are, how long can it be kept in a slurry state? And how easy is it to get rid of the water to tube up the paint?
insert pithy comment here.
October 6, 2023 at 2:39 pm #1528301These are the questions I have as well.
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