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Dry. Cracking Bear Skulls

Discussion in 'Beginners' started by joel potie, Oct 11, 2019.

  1. joel potie

    joel potie New Member

    I received two bear skulls from a friend who challenged me to repair them. He tried preserving them on his own, but they ended up looking pretty awful. They are cracking in several spots and still have a lot of grease coming out. I suspect he may have boiled them.

    Now, I am looking for some tips on how to tackle this new project.
    When doing my own, I have used Dawn to soak the skulls for weeks/months to remove the grease. I have heard that soaking in acetone can work well on more stubborn areas, such as the lower mandibles, is this true? How long would one soak in acetone, if this is true? Are there any techniques or products recommended for repairing a dry cracking skull and refinishing it?

    Thanks in advance.
  2. If they are cracking he over cooked them. Sad people boiling skulls think they cook them until the meat come off. NOT SO!

    Anyway you will need to seal the tub the skulls are in if you use acetone. It has a low temp evaporation point. Soak until the grease is gone.
    To fill the cracks thin super glue it he cracks and sprinkle baking soda in to the glue if the crack is large baking soda and then super glue in layers.
    joeym likes this.

  3. Sea Wolf

    Sea Wolf Well-Known Member

    As John said, try a long soak in acetone to start. You can buy the orange Home Depot buckets or any good bucket that has a 2 in the triangle on the bottom. You can easily put both skulls in one bucket if they are black bears. Leave them to sit for at least a couple of months as the grease is now throughout the bone. Check and see if they are better, if not, you can now try soaking them in a really strong ammonia solution 50/50 or more. Try and get the strong 10% stuff from the hardware store. Soak them for another couple of months. Due to the damage of the skulls, you want to handle them as little as possible to keep from breaking off loose parts. For degreasing them, this will be about the best you can do without further damage. You can let them sit in acetone for months as it won't interact with the bone at all. They can sit in the ammonia too but don't keep moving them around as the ammonia is water based and the wet bone will be looser than when dry. When you have done all you think you can, rinse off in hot water a few times and then put into peroxide to sit for a few hours to whiten them better then rinse again in hot water and drain. You can try running a bead of Elmer's glue in the larger cracks and then, gently, use a furniture clamp to bring the cracks together while wet and let them dry. If you fear they will damage more doing this, just let them dry. If they are powdery and flaking, you can now soak them in an alcohol solution of a resin called Paraloid B-72 for a couple of days and then dry. This will saturate the damaged bone with resin and stop any further disintegration. After that, as John said, packing the cracks with baking soda and dripping in super glue will solidify it in there and make a nice white fill that can be sanded smooth to match the skull surface. The paraloid fix will cost some money and you may want to skip that and just chalk this up to the school of hard knocks. Boiling a skull is usually a bad thing in the hands of many. If these are not specimens that mean anything to you, you may not want to be spending all this time and effort when good, raw bear skulls are available pretty cheaply for you to clean on your own. Yes, your friend challenged you to fix his mistakes but maybe he should be investing the time and money and learning to fix his own mistakes.

    Taking the time can fix things. This is a Russian Brown bear that was boiled. No cracks but it is full of grease and sat this way for several years.
    The below photo is the same skull after 6 months in acetone and 6 more months just sitting in ammonia.
    msestak likes this.