Horse Skull Question

I would say the grease settled in one side. That combined with exposure on the other. If you can submerge that in something, I use a Rubbermaid trash can for these, I use water and ammonia 50/50. It is a lot of ammonia but horses are greasy/oily pretty bad. The last one I did, I set it in a heated garage. The water was not heated but I just left it for about 4 or 5 months. If I had heated it, it probably would have gone faster. I don't think there is enough grease left in that to warrant changing the solution. Try using Dawn and ammonia heated but still leave it for a couple of months and see. Looks like there are some nice "wolf" teeth on that.
The last one I did looked like this when it arrived. Dripping oil and just plain nasty.


This is what I ended up with.

 

Wasn't wet and been been sitting for some time. It arrived in the summer and the heat was causing grease to be seeping out of the lower jaw. The rest was pretty well petrified.
If your heater doesn't appear to have any exposed metal keep an eye on it. Don't reach your hand into the water without unplugging it first just to be sure. If something is going to corrode, it won't be right away but it is a good habit to get into anyway.

As for space, You don't want to have a huge volume of water to heat but you also need to have enough solution to carry the grease away and keep it in suspension. It sounds like your tub will be ok. Just make sure the entire skull is covered well.

The only time I had that many skulls in a container was the time I tested myself. Bear, cougar, wolverine, wolf, fox, coyote, lynx and a couple of others .. all in the same container macerating and then degreasing. Was a huge pile of teeth but they all got sorted very quickly. Unless you have each skull in a mesh bag to keep the parts together, you are going to have an unpleasant time trying to get teeth to fit. With so many animals of the like kind together, the teeth will be all mixed together and most teeth will only fit correctly in one place. You will not be able to set random teeth back into the jaws.

The temp of 115 would be fine for the horse. If it drifts up to 120 it won't hurt anything. As for the acetone, for the sheer expense of buying enough of that to submerge your skull would be cost prohibitive. If your container does not have a 2 on the bottom in a triangle .. it will also be dissolved by the acetone. I only use it for last ditch effort skulls that are not responding to any other method.

 

That would work for degreasing but I would wonder if too many bags packed together might slow the process. Maybe moving them all around a few times a week would help. I know others have used mesh bags for maceration but the thought of rotting goo getting caught up in the material and having to handle that to get at what is inside gives me nightmares.

 

I'd drop that in a bath with iron out, that will remove iron from blood and minerals may have leached in from the ground as well and then put it back in the degreaser. Deadheads can be a pain, no question. When I do an iron out soak, In the morning I'll fill a container big enough with hot water and as much iron out as I feel will get the job done, drop the skull in, agitate the solution through the day and at the end of the day rinse it off well and back into the degreaser.

 

Ditto on the Iron Out. There is a recent post on here where someone had a pretty badly stained/discolored hyena skull. A soak in Iron Out did a lot for it. Look in the hardware store for the powdered version. Grocery store might have it too. After Iron Out, do NOT use peroxide. So, what you might want to do is use peroxide on it to whiten it then use Iron Out to remove the rest of the stains as best you can. Some stains will be permanent from it laying out and rotting on the ground but you can make a dent in them.

 

I have never had issues with soaking in iron out and back into degreaser and let dry, then into peroxide. In fact I have taken out of peroxide and let dry and then into iron out soak. I always rinse and dry before anything goes onto the next step other than from maceration to degrease, I only rinse there.

 

Nothing should remain enough to interfere with paint as long as it is completely degreased and dry prior to painting. That hinge location on bottom jaws can be a pain but they will come clean, it just may take multiple different formulas or applications. On things that will fit in a small enclosed container like that, I often use acetone to soak stubborn things like that. This I do outside and will leave it in there fro a week or two and then back into my degreasing solution, after the acetone has evaporated that is.

 

Those areas you circled are still greasy. Don't remember if you have already but try soaking it in a strong solution of ammonia. Gallon of ammonia to 3 of water. Let it sit. The horse skull I did took 5 months of sitting in ammonia to get the grease out. It wasn't heated, just room temp. Heating it might speed it up some but be patient. These are really greasy animals. Any paint used is going to bubble and peel off of any greasy area in time. If those areas are in places where she isn't going to paint on them it should be fine. With peroxide, when dry, nothing remains. It all breaks down into hydrogen and water. With Iron Out, after a soaking rinse, I think most of the product is leached out of the bone. I would not worry about either reacting to paint.

 

Scrolled back and saw that you were using ammonia. You are good with that. What I see is more iron/mineral stains than grease. If you have a barrel to hold enough water to cover the skull, mix up a solution of the iron out and let it soak for several hours. That should get rid of the mineral stains (most of them anyway) and you can see better where you have grease issues. I would put it back into the degreaser after that and keep an eye on it. It's going to take months to get the grease out of those joint areas especially. It will be up to the owner to decide when they are happy with it I guess. Your setup is a good one. That foam core pink stuff is great and a lot safer to handle than pink insulation. I do enough skulls that I made an outdoor hot box to do a bunch of them at a time. The interior of the box is heated to 90 which heats everything else inside to 90 too. Acetone can work but it is highly volatile and expensive. Unless you have a container that is acetone proof and you can seal it, I would not spend the money to use it. Ammonia is not volatile and you may have just gotten used to the smell of it. The stuff from the hardware store is ferocious and might not let you off so easily. The owner might not want to wait another 3 months but, as she is going to paint on it, she might not mind the grease in areas that are not part of her design.

 

If you can find the industrial stuff at the hardware stores, it's 10%. Cleaning supply places may have it too but the hardware store might be cheaper.