| Posted: Sat Jan 5th, 2013 10:44 pm |
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Don Burt
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When I'm tracing the paint will crawl and shrink sometimes. I was never certain as to the reason. The obvious thought is that the glass must be unclean. Dick taught us to clean the glass with a little moist whiting. That doesn't work for me. Clean it with alcohol, not any better. Clean it with lacquer thinner, not any better. Add airbrush thinning medium to the paint: makes it worse. Try vinegar instead of water...no better. But then it occurred to me why this happens: it's Satan that wills this problem to occur. There can be no other answer. So I added a little lightweight liquid soap to the paint. That fixes it. It all has come together for me and I'm painting glorious trace strokes that stay where I put them.
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| Posted: Sat Jan 5th, 2013 11:26 pm |
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David Crane
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Hi Don,
Your mention of SATAN! caught my attention......
Damn Satan!
Tantalizing message....
I am guessing you are using water and gum. Please correct me if wrong.
What is "lightweight" liquid soap may I ask?
Does it affect the fire in any way?
Happy glorious tracing!
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| Posted: Sat Jan 5th, 2013 11:42 pm |
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Don Burt
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Hi David. Maybe I overstated the infernal origin of the problems. I used some airbrush cleaning soap, which couldn't be anything special. I assume that dish soap would work. It doesn't affect the firing results.
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| Posted: Sun Jan 6th, 2013 12:26 am |
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Mary Clerkin Higgins
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Great observation. Thanks, I'm going to try it. I've always used a wash of the paint, rubbed off, to clean the glass.
Happy New Year! Mary
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| Posted: Sun Jan 6th, 2013 12:39 pm |
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Don Burt
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Google leads me to understand that the topics at hand are surface coating rheology, and surfactants, rather than demonology. If I understand correctly, the soap acts as a 'wetting agent': It reduces the surface tension of the paint mixture. If thats the case, we could try what the watercolorists use: 'Ox Gall'. I think its a lot cooler to assert that your paint medium must have a drop of 'Ox Gall', than it does 'Dawn Dish Detergent'. I also like the idea of 'de-ionized water' that I heard Art mention in a video for the Tiffany Angel exhibit. I want to have a reason to use 'de-ionized' water. I'm sure it will help something. Distilled water does apparently have a lower surface tension than tap water, but I doubt that there is a practical difference in paint made with distilled vs tap, because after all, you're adding powdered metals and glass back into the water. Still, you have to admit the appeal of using Ox Gall and de-ionized water in your paint. Last edited on Sun Jan 6th, 2013 12:41 pm by Don Burt
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| Posted: Sun Jan 6th, 2013 05:33 pm |
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David Crane
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Yes!
Exotic sounding secret stuff to confound the hoi polli and then you can charge more!
I'm still going to add "demonized" water to my repertoire and pretend I didn't hear right. Well maybe not for church work.....
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| Posted: Mon Jan 7th, 2013 01:19 am |
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Vic
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since I am NOT a painter, I will add my 2 cents. How do you clean your brushes? Is there a possibility of "stuff" (technical term) on the brush causing your problem?
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| Posted: Mon Jan 7th, 2013 04:35 pm |
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Mary Clerkin Higgins
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It's usually an issue of something on the glass that repels the paint, so a wetting agent is an interesting idea. You'd still have to clean the glass well, but it might encourage smoother paint flow. Some use glycerine for that.
Best, Mary
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| Posted: Mon Jan 7th, 2013 06:32 pm |
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Don Burt
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Vic wrote:
since I am NOT a painter, I will add my 2 cents. How do you clean your brushes? Is there a possibility of "stuff" (technical term) on the brush causing your problem?
I wash my tracing brushes with plain old dish soap. I can't recall ever having had the crawling problem using an oil medium, but I don't use the same brushes for oil. Clearly the glass surface quality is causal. Because you can be painting along with a tracing brush fine, and all of a sudden the paint won't stay on a spot. You clean up the spot, and sometimes it helps, but sometimes it still rejects the paint. Its a pain to be cleaning a piece that you've already got paint on, and I've had some spots that I've cleaned the hell out of (to continue the motif) that still resisted every attempt to trace on it. So I look for a solution other than fixing the cause: I look to the paint and wish that it was less crawly by nature. My tracing paint is usually:
Paint
Klyr-Fyre liquid medium (a CMC dilute) - I can't believe its much differnt than gum-arabic
Rubbing Alcohol or
Water - scandalously ionized
Last night I was tracing the same piece that provoked this thread, and hit another bad spot. I cleaned the spot. I added a few scant drops of airbrush soap to the little bowl of water, and cleaned my brush with it, and regathered paint, and tried again and it failed again. I had hoped that would be sufficient. So next I added a drop of soap directly to the paint on the pallet. I'd guess it was 1/50th of the medium. And then I was able to trace over the spot.Last edited on Mon Jan 7th, 2013 06:32 pm by Don Burt
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kathy
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I'm still reeling about the Ox Gall... Now I have to google Klyr-Fyre. What the hell (staying on the same theme)is a CMC dilute?
Kathy J.
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Don Burt
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CMC is a binder. Potters use it. Some chemical whose last letter stands for cellulose.
Klyr-Fire (spelled correctly, but stupidly) is a Thompson Enamel product. It's a nice medium for water or alcohol.Last edited on Mon Jan 7th, 2013 08:28 pm by Don Burt
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gwsg
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Don,
When you hit one of those spots where the paint won't take, slowly breathe moisture/steam from your mouth over the spot and immediately trace it again. The paint will take.
Cheers
Geoff
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Don Burt
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gwsg wrote:
Don,
When you hit one of those spots where the paint won't take, slowly breathe moisture/steam from your mouth over the spot and immediately trace it again. The paint will take.
Cheers
Geoff
I'll give it a try. But I'll bet its more effective if you take a drink of ox gall first.
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gwsg
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Sorry, I meant vapour not steam. Must have been all the talk about demonology.
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joseph2bears
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Hi Kathy, and friends. CMC is Carboxyl Methyl Cellulose. It is derived predominantly from cotton lint. It comes in 3 different grades. Industrial grade is used by potters as a binder in glaze formulations. It is a white/tan color and can be obtained from any ceramic supply house. It is also used by glass artists to make a glass paste with powdered frit. This is used in the Pate de Verre casting process or in creating sculptural 3D effects on flat glass. There has been some chat about the impurities in the industrial grade leaving unwanted residues in the fired glass and for that reason some artists prefer the food grade (which of course is more expensive). I have used both and cannot tell the difference in the little bit of work I have done.
The food grade CMC is eggshell white. Some glass distributors now stock and sell it, but you are better off going to bakery outlet suppliers. If you check the ingredient label on your next package of tortillas, you will find CMC listed.
The pharmaceutical grade is ultra purified and therefore very expensive. There is no reason to use it in glass work. If you check the ingredients label on gel-type eyedrops, you will find CMC listed.
CMC powder is mixed with boiling water. It forms a clear gel that is lumpy. You leave it overnight and it smooths out to an even consistency. Depending on the ratio of powder to water you can make a gel that is as thick as Jello, or as thin as syrup. Always prepare on the thick side. You can always thin it to the consistency you desire by adding water, but you can never thicken it by adding more powder. Adding powder simply does not work. I always use distilled water and I add a tablespoon of rubbing alcohol when stirring the mixture. The rubbing alcohol acts as a preservative and lets me keep the mixture in the shop at room temperature for up to 6 months. CMC is organic so it will grow mold if left unrefrigerated or untreated with alcohol. I find the alcohol treatment easier than refrigeration. After 6 months the mixture starts to decompose and gets runny. Throw it out and make a new batch as needed.
CMC does burn out cleanly when fired. Of course, impurities/minerals in the water or the industrial grade powder will be left behind in the glass. Some claim they have seen a haze in the glass left by these impurities, but I have not. Of course, I am stage 2 cataract now so there are things I don't see very well any more.
I hope this has been helpful.
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kathy
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Am I missing something? I understand the three explanations for it's use, but why paint with it? What are the benefits?
Kathy J.
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Don Burt
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kathy wrote:
Am I missing something? I understand the three explanations for it's use, but why paint with it? What are the benefits?
Kathy J.
I think it raises three questions.
1. Why use a liquid medium w/binder? (Klyr-Fire, 7up, Liquid Gum Arabic)
2. Why make your own liquid medium? (boil CMC, boil powdered sugar)
3. Why use powdered gum arabic in your paint?
My answers are:
1. convenience. Binder strength isn't that important. Premixed medium facilitates consistent paint. But really, its just convenient.
2. I don't know. I don't make my own. Some people get off on making their own stuff. A lot of glass fusers want to make their own paint, even, to add a kind of alchemical panache to their artist's statement. Actually I think the things that we choose to do manually, and what we choose to do with a machine or computer, and what we choose to let others do for us, says a lot about our art. But thats another discussion. I need to stop or this thread's going to rival an H-net putty thread.
3. You want to control the binder strength carefully in each batch of paint, a little more gum arabic for tracing, less for a matt, less yet for an alcohol overmatt. I don't find myself doing that. I put a teaspoon of enamel on a palette, squirt about an equal volume of KlyrFire in it, and work it with the knife adding alcohol or water until its like I want it. The resulting paint is delicate in green strength, but I get by ok. Except when the goddamned paint crawls.
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kathy
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Hi Don,
I use a liquid medium; Reusche D1368. It behaves like an oil and thins with water, stays open long enough to play. Simple. No binder required. Cleans up in a flash. I supose you could add a binder especially if you wanted to work on the piece once it is dry, prior to firing. For the most part, I work wet when using this technique.
Sounds like our approach is similar, just different liquid mediums. We may have different ratios of pigment to medium. Through the years, I've watched China painters mix stiff batches of paint; a toothpaste consistency and thin with a very "conditioned" (the medium and/or thinning adgent is worked into the hairs of the brush) brush, drawing from the main mixture into the center of the palette. I am fascinated with how methodical these steps are.
So, I guess I'm more fussy about the application process then measuring? Shoot...through some ox gall in there and kiss a cow.
Kathy
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Don Burt
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I have a little D1368 that I got with a Reusche sample kit. I used it for some screen printing because it is a propylene product and those are supposed to be good for screen printing if you want a water miscable medium. D1368 is a propylene/cellulose (not CMC cellulose, but something similar) product, apparently. I looked up the MSDS. It would be suitable as a safe laxative irrespective of any value as a paint medium.
Will you teach how to use it in the Painting Intensive class?
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