MikeC Report post Posted October 11, 2011 I have some gum copal, not sure what kind or origin, that's all the container says. Thinking of trying to make some varnish with it. I found this recipe Take copal in powder, 1 oz.; essential oil of lavender, 2 oz.; essence of turpentine, 6 oz. Put the essential oil of lavender into a matrass of a proper size, placed on a sand-bath heated gently. Add to the oil while very warm, and at several times, the copal powder, and stir the mixture with a stick of white wood rounded at the end. When the copal has entirely disappeared, add at three different times the essence almost in a state of ebullition, and keep continually stirring the mixture. You varnish experts... Joe? What do you think of that recipe. Are there other recipes that you would recommend? Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 Kremer pigments lists 15 different types of copal If you succeed in making varnish from the material you have will you ever be able to make more of it? I wouldn't bother making varnish from an unknown resin, the chances of success are limited and the reward for success is frustration. The recipe seems sketchy. It assumes a melting point of 100c (water boiling point) which is very low-likely to result in a varnish that's too soft and delicate. Besides most copals have a higher melting point. Oded Quote Share this post Link to post Share on other sites
Michael_Molnar Report post Posted October 12, 2011 Mike, Oded is on target. Don't go down a path just because it's there. Quote Share this post Link to post Share on other sites
actonern Report post Posted October 12, 2011 And PLEASE, if you do, don't be using power tools to stir it! :) :) :) :) Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 And PLEASE, if you do, don't be using power tools to stir it! :) :) :) :) LOL Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 I have almost a pound of it. I may as well try doing something with it. what the heck, just for fun. In case no one noticed. I'm a code slinger by profession, sometimes fx trader, and an all around computer nerd. So I'm the guy who goes in the server room and says Hey! let's press this button and see what happens! LOL different varieties. hmm... is there any way to guestimate what kind it might be by it's melting point or hardness or specific gravity or something? Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 You've been warned! Most copals need to be 'run' (melted and cooked) before they will fuse with oil to make varnish. First thing i would do is crush a bit and put it in alcohol. If it's soluble in alcohol you're done. If not then I would put it away and not think about it for a few years. Oded Quote Share this post Link to post Share on other sites
Jeffrey Holmes Report post Posted October 12, 2011 I have almost a pound of it. I may as well try doing something with it. what the heck, just for fun. In case no one noticed. I'm a code slinger by profession, sometimes fx trader, and an all around computer nerd. So I'm the guy who goes in the server room and says Hey! let's press this button and see what happens! LOL different varieties. hmm... is there any way to guestimate what kind it might be by it's melting point or hardness or specific gravity or something? Try covering a bit of it with alcohol. If it softens, it's probably Manilla Copal. Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 You've been warned! Most copals need to be 'run' (melted and cooked) before they will fuse with oil to make varnish. First thing i would do is crush a bit and put it in alcohol. If it's soluble in alcohol you're done. If not then I would put it away and not think about it for a few years. Oded Sounds like a plan, at least the alcohol part. Maybe I should use everclear so if the copal doesn't melt... So manila copal is the only kind that will dissolve in alcohol? I'll try it and see. Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 Lots of varnish wisdom at this site including a section on cooking an oil varnish. Oded Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 Thanks, I read Darnton's pdfs. I'll read them again. Downloaded and saved them. Quote Share this post Link to post Share on other sites
Brad Dorsey Report post Posted October 12, 2011 I have made spirit varnish for retouching by dissolving copal in alcohol and filtering it, then mixing it with dissolved, filtered sandarac and store-bought pre-mixed white shellac. Quote Share this post Link to post Share on other sites
Adam Edwards Report post Posted October 12, 2011 What you have is ok , try adding it to your normal varnish ( cold ) to fortify it Quote Share this post Link to post Share on other sites
CarloBartolini Report post Posted October 12, 2011 This book has a lot of info on resins, may be able to help you identify the kind of copal you have. Good luck and have fun, don't blow anything, except speakers. http://openlibrary.o...s_and_varnishes from the book: In fusibility the hardest copals have the highest melting points. Zanzibar melts at 24O°-25o° C.: West African copals melt at 120°-180° C.; Sierra L,eone, 125°-137° C.; Manila and Kauri, H5°-i40° C.; Hymenea copal (fossil), i8o°-200° C., but the softer varieties melt below'115° C. The fusibility depends essentially on the age, the new varieties fusing at lower temperatures. In view of the complexity of composition no fixed temperature can be assigned to any variety. It must be pointed out that the resins first soften and then slowly liquefy and the running temperature is the point when suitable fluidity is attained which may or may not coincide with the melting point. For each gum there is a temperature below which it cannot be incorporated with linseed oil. Morrell, R. S. (Robert Selby), 1867-1946; Waele, A. de (Armand), b. 1887. Rubber, resins, paints and varnishes (Kindle Locations 1727-1733). London, Baillière, Tindall and Cox. Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 Thanks Carlo, I downloaded the book Quote Share this post Link to post Share on other sites
CarloBartolini Report post Posted October 12, 2011 Thanks Carlo, I downloaded the book I love kindle search......found this, lots of good info on identifying copal Chapter IV Copal The Manufacture of varnishes and kindred industries - 1908 http://openlibrary.o...dred_industries Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 Very cool books but there is a danger of being completely distracted and spending the rest of your life chasing ephemera. Keep in mind that basically violin varnish was found to contain two ingredients, oil (linseed or walnut) and pine resin. Varnish making and research should be regulated by the DEA as being highly addictive. You've been warned ! Oded Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 Hi Oded with the copal I was thinking more of a ground than a varnish. The ground I've been experimenting with is mostly pine resin. It has some nice charactheristics but some other resin might be harder & more durable. Maybe a blend, one for looks and one for toughness. I'm already adictied! Quote Share this post Link to post Share on other sites
Jeffrey Holmes Report post Posted October 12, 2011 So manila copal is the only kind that will dissolve in alcohol? I'll try it and see. Since you've downloaded the book and pdfs, you probably know more than I do now. :-) I don't believe Manilla Copal is the "only" one, but it is common, and goes into alcohol relatively easily. It can also be melted and cooked into oil. I've made some rather nice workable oil varnishes (in combination with one or two other resins) with it. Brad mentioned touchup varnish. I sometimes use a small amount (low ratio w/other resins) in alcohol based touchup varnish as well, but careful... it can be rather shiny. Used in larger ratios, and allowed to "settle out", it can make a very good base for fill varnish. Quote Share this post Link to post Share on other sites
fiddlecollector Report post Posted October 12, 2011 I made some varnish recently using copal that i had had lying about for years, which Joe Robson said was probably Pontiak. I run it twice and left it cooking for quite a while after initially not heating it long enough.The colour was very nice and i cooked it directly afterwards with some slightly softer resin and oil. It turned out very nice ,good colour and it drys very well and fast,even without UV. Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 http://www.pearsondental.com/catalog/product.asp?majcatid=8&catid=2873&subcatid=1763&pid=61457 Copal varnish used in dentistry? Cool! I can do my own dental work now! Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 It must be very hard to stand up to chewing. Quote Share this post Link to post Share on other sites
MikeC Report post Posted October 12, 2011 I found more recipes... http://chestofbooks.com/crafts/metal/Tin-Sheet-Iron-Copper-Plate/Copal-Varnishes.html I'm cooking chili tonight. Hopefully I won't get the recipes mixed up. Of course, the chili spices might give a nice brown stain to the violin but I don't think my teeth would look good with a golden ground. hmmm... Quote Share this post Link to post Share on other sites
Michael_Molnar Report post Posted October 12, 2011 And PLEASE, if you do, don't be using power tools to stir it! :) :) :) :) Why ruin my fun? John Masters suggested this. Quote Share this post Link to post Share on other sites
Oded Kishony Report post Posted October 12, 2011 I would guess that he's doing this for his emulsions. Normally varnishes don't need that much stirring. OK Quote Share this post Link to post Share on other sites
