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#1 |
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Gentlemen,
The knife from the attached pictures has been found in North-Western Bulgaria. To me, it looks like a short seax, but I may be wrong and I would be very interested in your opnion on its appropriate identification. The hilt looks like ivory. Does anyone know if it is normal for ivory to get this greenish hue after being in the ground for a while? Finally, my friend who owns it wonders what is the best way to preserve a blade in such a condition? Should he try to conserve with phosphorus or would some kind of lacquer be more appropriate? Thank you in advance for your answers, Teodor |
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#2 |
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looks very seaxy to me! the ivory could have picked up some copper salts from any brass or bronze (the bolster/guard possibly?) in the area, looks like the green starts at the guard and works it's way up the grip....
maybe looked somewhat like this when it was a bit newer: ![]() |
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#3 |
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Location: Bavaria, Germany - the center of 15th and 16th century gunmaking
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Hi Teodor,
As to conservation, there is only one truly professional way to save the piece once and for all. Put the item just the way it is right away in a water proof box and cover it with distilled water. The water should be renewed daily until no more bubbles can be noticed arising. By then, all the obnoxious yellowish salt particles should have been washed out. Next, thoroughly dry the piece in an oven at ca. 150° Celsius for about two hours and let it cool down. Then make a watered solution of tannin, a yellowish powder available at drugstores, and let the item rest in that solution, completely covered, for about 24 hours; turn it around one or two times. Take it out and rub it dry and there will no more problems arise whatsoever. The method you suggested is purely chaotic and bound to destroy the item in the long run as the salt particles will unharmed remain in the metal and continue their destructive work beneath the lacquer or wax layer. Any acid cleaning will lead to heavy substantial losses and ruin the surface irrevocably. Best, Michael Last edited by Matchlock; 8th October 2009 at 11:22 AM. |
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#4 |
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I do not think the grip is actually of ivory, it is most probably staghorn or bone instead.
I have often seen excavated bone grips turned green, mostly from copper oxidation (verdigris); maybe the iron sleeve at the base of the grip is copper or brass brazed. Michael |
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#5 |
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Michael,
Thank you very much for your reply and conservations tip - I will advise my friend to try the procedure you suggested. In the final step, is there a recommended ratio for the tannin solution, such as this many grams of tannin per this many liters of water? Thank you, Teodor |
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#6 | |
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#7 |
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Hi Teodor,
I would suggest a ratio of tannin : water of 1 : 4. Sorry for not mentioning that. Best, Michael |
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#8 | |
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You have been of tremendous help. Sorry for all of my questions, but me and my friend are new to this field, as our collections tend to be of mostly 19th century items. I was just wondering, for all the manipulations, should the seax be submerged blade down into the distilled water/tannin solution with the hilt left sticking out of the container, or is it safe to submerge the hilt as well? I am afraid disattaching blade and hilt is impossible. Thank you, Teodor |
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#9 |
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My understanding is that washing may be the best option, and that the tannin treatment really doesnt do anything.
For the last word, you may be interested in this book, recently published, pretty much the only book on conservation of iron/steel. http://www.amazon.com/Iron-Steel-Cor.../dp/1904982050 |
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#10 | |
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Sorry to differ but in my 30 years of restoring experience, tannin has definitely proved to have a both cementing and tightening effect. Moreover it generates a very smooth and homogenous black surface. Nor more problems with material losses of excavated iron objects! You may ask any good museum restorer. Michael |
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#11 |
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Teodor,
Let the bone covered hilt stick out of the tannin solution, otherwise it will get blackened. Michael |
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#12 |
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Re iron and tannin: Iron tannate is a very nice, fairly permanent black ink (it's the basis of that iron and oak gall medieval ink recipe).
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#13 | |
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Michael- I'm no expert, and I'm not trying to contradict you or your experience- just passing along info I gathered from Dr. David Scott, Chair of the UCLA/Getty Conservation Center, professor at UCLA, and author of the two most important metals conservation books to be published yet. Regarding the knife, does it appear the bone handle has been turned to shape? |
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#14 |
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Thank you everyone,
I will leave it up to my friend, but I do not see any reason why he should not try the tannin solution. I am not certain what "turned to shape" means. Regards, Teodor |
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#15 |
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I was just wondering if the bone handle was turned on a lathe
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#16 | |
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#17 |
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lathe for turning objects
![]() a piece of wood or bone held between two points and rotated, a cutting tool (chisel) is then pressed against it to produce a rounded object of circular cross section like a chair leg, or a knife grip. the illustration is the earliest known inscription found in ptolomeic egypt. the rotation is by a cord wrapped around one end and the free ends are pulled to spin the object alternately clockwise and counter-clockwise. similar lathes are still in use in parts of asia. see 'pole lathe' in google. this is 'turning'. another one, foot operated ![]() (i'm a degreed mechanical engineer, so my mind is geared to know these things ![]() |
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