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About jonnie

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  1. Enamel Chemistry?

    Yes you are probably right once cured but spraying really does up your potential exposure - I regularly use fibreglass and cyanate hardners in paint brush application (non spray) the problem with spray is everything goes airborne not just volatiles - occassional use for me is fine but I dont want occupational exposure without a whole lot of investment in spray booths and so on.
  2. Enamel Chemistry?

    HI Biglou Interesting searches on these products ! Not sure about the high temperature stuff but the others I believe are polymers ( resins ) which are sprayed - not unlike a "2pak" car paint. I looked into 2pak paints but the toxicity issues put me off as the catalyst is often a cyanate compound - one thing to layer by painting ( for instance fibreglass ) but another to atomise in a spray gun which is a game changer - probably ok to use a spray can now and then but I wouldnt want to be exposed on a daily basis. Enamel does contain heavy metals but the way I use it is pretty safe, hand application (no spray) and wet grinding (no dust) with water filtration to remove dust before the water re-enters the environment. Thanks these are certainly interesting leads and I will dig a bit deeper.
  3. Enamel Chemistry?

    Thanks Tyler - it would be great for me if your suspicion is correct as that would suggest that copper that has been electroplated is as good as regular sheet copper (with a few assumptions of course!). >>"It's true that you've got some time and expense ahead of you, but enamel frit is going to be be absolute least of your costs". Yup - I am tying together several techniques and each has questions and ultimately requires me to invest to get the right gear and take the leap. I guess the reason I dont want to rely only on experimentation and observation is that the finished products will be sold ( one man artisan business ) and I figure that just because an enamel "looks" ok it doesnt mean that the bonding is as good as it could be or that fatal stresses are present just waiting to make the whole thing go "ping" when someone knocks it so I would like to understand whether metal-enamel bonding or COE is the dominant issue here. Appreciated your reply! Jon
  4. Enamel Pigmentation - Diy?

    Hi Tyler, I should have added in the original post that the intended use as far as Thompson are concerned is as a paint on surface pigmentation so it is performing as the manufacturer expects. To answer your other question single color enamel (powders) are firing just fine. Most of the enamaling texts/books suggest that true blending of colors is not possible but I guess I am asking is how the manufacturer managed an even dispersion of a pigment in the first case. When I use a light blue enamel on its own I cannot magnify it sufficiently to see anything else but light blue - no pigment blotchiness appears its smooth and uniform. What I am hoping to uncover here is whether I should be trying different pigments or whether my temperatures are simply too low to achieve real color blending. It might be the case that if someone wants to make an inbetween color from two other colors they need to fire to a much higher temperature for a longer time and then re-grind the result to get a new single color enamel? I am getting the impression here that just because a glass or frit has fused its not necessarily really mixing or allowing diffusion of pigment in the way that many liquids would behave. I am wondering whether temperature or "soak" time are variables that I need to explore. I could imagine going to the trouble of building a small high temperature kiln just for the purpose of being able to alter colors (from purchased 'base' colors) to my liking - it would be worth it for me.
  5. Enamel Pigmentation - Diy?

    In case anyone finds it interesting... two pics. The first (blue and white) shows a photo taken through my computer USB-microscope at 400x of a finely mixed blend of a light blue and off-white enamel showing total refusal to blend color at all. The second (again 400x) shows the result of sprinkling a mustard colored ceramic pigment (from Thompson enamels) on a freshly ground off-white enamel surface - the whole lot was fired at around (850C | 1562 F) for a minute or so using a torch and then reground to remove the unwanted gloss finish. Some pigmentation does appear to have taken into the surface but I know from previous experiment that a few more passes with the diamond file and it would all be gone - its only superficial no real depth or penetration. I have tried mixing the ceramic pigment into the enamel ( rather than just dusting on the surface as in the mustard colored case above ) but the results are again only skin deep as the pigment all seems to rise up to form a surface layer but nothing within the "body" of the enamel - three strokes of a diamond file and its all gone. Again in brief I am hoping to connect with someone who can point me in the direction of information about how pigments are introduced to (enamel) frits and I suppose ultimately info on how to create a colored frit from scratch. In reality I am happy to simply purchase existing powdered enamels and then to try and shift the color by small degrees to give myself an expanded palette to achieve amongst other things subtle color gradients. Jon
  6. Enamel - microscope photos of surface

    uploaded some photos taken of results of attempts to "Blend" color with Thompson enamels. Looking for information to help me learn more about pigmentation of frits.
  7. I would like to ask those with experience about pigmentation of enamels ( the type intended for use on metal ). I am interested in creating "inbetween" colors for color graduations. My experiments have been as follows... 1. Finely mix two differently colored powdered (opaque) enamels >>> result - "spotty" 2. Finely mix, grind and sieve two powdered enamels >>> result - much better but still "spotty" 3. Finely mix, grind and fire ( typically 850 C | 1562 F ) two enamel powders, regrind, re-fire and repeat >>> result - best yet - hard to tell due to limitations in my method ( need to build a decent device for reducing larger flakes before grinding to a powder ). 4. Introduction of ceramic pigments from Thompson enamel supplies. I believe these are fritted and not pure oxides >>> result poor - pigment floats to the surface and is grainy. Not the desired result since I then go on to grind the surface smooth for a matt finish which is my preference - pigment is not taken into the body of the enamel its a superficial surface effect. Any pointers to reference material or similar that will help me educate myself on the subject of how pigments are ( or are not ) fully absorbed into frits and glazes would be gratefully received. At the moment I am working on the assumption that perhaps my temperature range ( traditional enamel temperatures up to 850 C | 1562 F ) are not capable of fully dissolving pigments into the glass - however I read somewhere that good pigments are insoluble in glass so I am probably off the mark here? Bit confused! Jon
  8. Enamel Chemistry?

    Dear Tyler and all, I hope Tyler will not mind me adding questions on a related theme... I am interested in enamelling copper plated steel - enamel stockists always seem to supply either a special base coat for steel ( onto which they say regular copper enamels can be used ) or a specialised range for steel. I ask myself whether this is a bonding issue or a thermal expansion issue as this will determine whether a copper enamel or a steel enamel should be used to enamel copper plated steel. My guess is that its to do with bonding 1. Most online sources of expansion data suggest that steel is actually closer in terms of expansion coefficients to most glasses than copper, I am not sure about enamel frits, I am still struggling with the kind of COE Tyler mentions "258-360 (cubic expansion)" compared with the data presented (say here) http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html 2. If its all about expansion then its interesting that a thin layer of "steel base coat" can then reportedly iron out the imcompatiable expansion rates of the materials either side ( steel and regular copper enamel ). Please rip through my inexperienced guesses. I know the obvious answer is to suck it and see but I have significant investments in time and cash ahead of me and I want to start on a path that is more likely to succeed. Advanced apologies if I have hijacked the thread - I am a newbie but I did figure this was sufficiently ontopic. I would also like to ask questions regards how pigments intersperse in frits at different temperatures as I am very much intested in making subtle changes to the colors of purchased enamels but I think I should probably start a new thread for that one. Jon