Liquid Asphaltum
Printed From: Collodion Photography
Category: Workshops & Events
Forum Name: Workshops & Demonstrations
Forum Discription: Announcements and information for wet plate Collodion training and demonstrations.
URL: http://www.collodion.com/forum_posts.asp?TID=436
Printed Date: 18 April 2024 at 22:28
Topic: Liquid Asphaltum
Posted By: quinn
Subject: Liquid Asphaltum
Date Posted: 22 February 2006 at 20:34
Has anyone ever tried baking tins with liquid asphaltum? ------------- Regards, Quinn Jacobson |
Replies:
Posted By: Guests
Date Posted: 22 February 2006 at 21:19
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From what I have heard, it doesn't work for japanning tins, but it does work
(if thinned a bit) for blacking the back of ambrotypes. |
Posted By: admin
Date Posted: 23 February 2006 at 06:01
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Thanks Jason. It would definitely make a good blacking for Ambrotypes. I wonder what the issues are with it? The problem with experimenting with "surfaces" is that you risk messing up your silver bath and $120 per pound, it's a big risk. I've messed around enough to know that you can spend days, sometimes weeks, trying to recover a bath from an experiment, so it's expensive both in time and money. Maybe I should write a grant or two for experimenting with wet plate chemistry. That way, I could try everything without going broke. ------------- |
Posted By: PastInk
Date Posted: 30 March 2006 at 06:56
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Just stumbled across this thread and it has made me curious. I checked the maker's web site for more information and have emailed them for an MSDS and sent a long a couple of questions. My first impression of this product is that it is just what it says it is "asphaltum". Early Black Japan formulae call for chloroform, asphaltum and Canada balsam, or from the Silver Sunbeam oil of turpentine, asphaltum and Canada balsam. These were suitable for cold coating. However, Estabrooke described the tin type japanning as simply asphaltum (tar) in linseed oil. If the linseed oil used is boiled oil or stand oil which are quite different from standard linseed oil as the cross linking process has been started and carried along to a particular degree, then you have made a simple drying oil varnish. The basis of all early Japanning finishes was the "stoving" of a dried film capable of cross linking through high heat. The older the boiled oil the thicker it becomes and the better for use. At that point I would add a bit of turpentine or mineral spirits to thin for use. Apparently multiple coats were applied sometimes to the tin prior to use. Thin coats would always better in this regard. Well I will try some as soon as I can get my hands on some asphaltum. Sounds like an experiment is needed. Anyone been there already? Mark MacKenzie ------------- Art Conservator, Electronicist and Sometime Wet Plate Photographer Alcalde, New Mexico |
Posted By: admin
Date Posted: 30 March 2006 at 10:22
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Mark, ------------- |
Posted By: PastInk
Date Posted: 30 March 2006 at 15:35
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Great Quinn. I looked at the japanned plates you are carrying and thought that you were already into using that or a similar material. I have done a lot of research over the years in historical finishes. It is part of what I do professionaly. I would think of working with an HVLP spray gun (a touch up gun should work well). Set up a rack, you will have to figure out whether it should be inclined and if so how much. I think the less pitch angle the better. Thin the coating only as much as needed. I would experiment with whether mineral spirits or using MEK which would evaporate much more quickly might work well. Several thin coats with drying time may be the answer. I don't know whether stoving in between is the answer. I might guess that a light heating to drive off residual solvent is going to be necessary. When you are multicoating you must not have trapped solvent. You might find that the first heat/curing while you are building coats might work with IR lamps like chick brooder lamps arranged a foot or so above the drying plates. A second coat, a bit of air dry and then under the lamps again. Getting rid of the solvent prior to stoving should really help. Final stoving should be driving off the very last of the solvent, and volatiles of the resins. The rest of the stoving/heating process is causing cross linking within the linseed oil. The asphaltum is an inherently non-cross linking material or so I believe. When doing multiples of anything for small runs I always found time savings in doing several things at the same time. Well you know what I mean. Spray the plates, set to dry. Go do something else which makes you happy or money or both and so on. By the way, how are you degreasing your tin plate to start with? If you are using solvent degreasing and having many rejects I would strongly suggest going to an alkaline built detergent. Simple ones can be made with dishwasher detergent. They are highly alkaline. Wear gloves. If you heat the water to 150 degress F. there is a reaction wherein further alkali is released from the soap and it is really alkaline. This is one of ther reasons the dish washer instructions talk about needing 150 degree F or there abouts hot water. You can just use the soap in hot water. If you need more alkalinity for cleaning just add some sodium bicarbonate, about a couple of teaspoons per quart of washing liquid. The alkaline nature of the bath even though it is water prevents the sheet steel from corroding. It can't corrode, it is passivated at that pH. Well, you have plenty of time to rinse in hot water and air dry under the IR lamps if you wish. This is one of our regimes used in conserving archaeological iron artefacts. Gosh this is getting long winded. Hope there is something in here you can use. Let me know how things are with your process. What I can't help with I will emulate in my own practise. Regards Mark MacKenzie ------------- Art Conservator, Electronicist and Sometime Wet Plate Photographer Alcalde, New Mexico |
Posted By: quinn
Date Posted: 30 March 2006 at 16:54
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Thanks Mark! That is some great info. I may pick your brain a bit about modify/streamlining this process. ------------- Regards, Quinn Jacobson |
Posted By: autochrome
Date Posted: 28 April 2006 at 13:59
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Quinn - I do reverse glass painting and use asphaltum as a protection after
you apply the gold leafing - The problem with asphatum is the more you thin it the less it adheres to the surface - Baking it on might solve that problem. john |
Posted By: quinn
Date Posted: 01 May 2006 at 07:56
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Hello John, I ran a few tests with this and found that it works quite well. However, you are right about it losing it ability to adhere as it is thinned down. I don't want to spend the time doing three or four coats and baking each one. I'm convinced that it CAN be used to make Tintypes, no doubt in my mind, it's just finding the right combo of mineral spirits and baking times. ------------- Regards, Quinn Jacobson |
Posted By: Petzval Paul
Date Posted: 10 May 2006 at 08:05
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Morning y' all, I really liked the way that the liquid asphaltum looked on Quinn's "pulling the cap" ambro and I'd like to give it a shot. In John Coffer's "Doer's Guide" he suggests using "Naptha" to thin it out. I would definately prefer to stay away from such a volite and noxious chemical...are mineral spirits OK for thining it? Any suggestions as to a ratio for mixing? Oh, and should I paint or pour? Thanks for any advice in advance. - Paul ------------- www.sacredbluephoto.blogspot.com |
Posted By: admin
Date Posted: 10 May 2006 at 08:09
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Hi Paul, Mineral spirits worked great for me. As far as ratio, start with small amounts and work up. You'll find what you like. ------------- |