Cleaning Mammoth Tusk Pieces

[Opera Director]

I just purchased some beautiful mammoth tusk pieces that I will hopefully restore into a tusk that will be at least 20 inches long down to within 2 inches of the tip (which is missing).  It is a project I am working on with my daughter.  I want to start by cleaning the pieces which are very dusty and dirty.  I read to avoid water and maybe use rubbing alcohol but many of the pieces have a beautiful blue color to them and I am afraid of ruining that.  Any suggestions?  Thanks in advance.

[Ptychodus04]

1 hour ago, Opera Director said:

I just purchased some beautiful mammoth tusk pieces that I will hopefully restore into a tusk that will be at least 20 inches long down to within 2 inches of the tip (which is missing).  It is a project I am working on with my daughter.  I want to start by cleaning the pieces which are very dusty and dirty.  I read to avoid water and maybe use rubbing alcohol but many of the pieces have a beautiful blue color to them and I am afraid of ruining that.  Any suggestions?  Thanks in advance.

 

Can you post some photos? Avoid water at all costs. I would also avoid rubbing alcohol for this reason as most is only 30% alcohol. Denatured alcohol (available in the paint department at hardware stores) is a better option. If the blue color is part of the fossil itself, the alcohol shouldn't bother it.

[steelhead9]

The blue color is due to vivianite present during mineralization. It is usually paper thin and very easily lost in preparation. Abrasives will blow the color off the tusk. The only way I have found to prep a tusk with vivianite is to very laboriously sand it. Here is a a photo of a blue tusk I prepped by using a dremel with a small disk. I used fine sand paper with sticky backing cut to the size of the dremel disk. The tusk was very rough and covered with dirt when I started. It took FOREVER, but I managed to retain all of the blue color. Any solvent or consolident will destroy the vivianite. I finished the tusk with a coat of buffed butchers wax. Good luck!

[Ptychodus04]

3 hours ago, steelhead9 said:

The blue color is due to vivianite present during mineralization. It is usually paper thin and very easily lost in preparation. Abrasives will blow the color off the tusk. The only way I have found to prep a tusk with vivianite is to very laboriously sand it. Here is a a photo of a blue tusk I prepped by using a dremel with a small disk. I used fine sand paper with sticky backing cut to the size of the dremel disk. The tusk was very rough and covered with dirt when I started. It took FOREVER, but I managed to retain all of the blue color. Any solvent or consolident will destroy the vivianite. I finished the tusk with a coat of buffed butchers wax. Good luck!

 

Now, that is some useful knowledge. Thanks for sharing.

[RJB]

One learns something eveyday on this forum. 

 

RB

[Opera Director]

Wow, beautiful!  Great tips from you and Ptychodus 04, many thanks!  The blue extends only part way down and is very chalky, I don't think it is going to last.  My next thought is about adhesive and whether to fill or not.  There aren't any real voids, just crack and I like a more natural look even with flaws. Here is a couple of photos, there are eleven pieces total.  Won't be a museum specimen by any means but I am thrilled to have them!!

 

 

12 hours ago, RJB said:

 

 

 

IMG_0489.pdf

[steelhead9]

On 12/15/2017 at 7:33 PM, Opera Director said:

Wow, beautiful!  Great tips from you and Ptychodus 04, many thanks!  The blue extends only part way down and is very chalky, I don't think it is going to last.  My next thought is about adhesive and whether to fill or not.  There aren't any real voids, just crack and I like a more natural look even with flaws. Here is a couple of photos, there are eleven pieces total.  Won't be a museum specimen by any means but I am thrilled to have them!!

 

 

 

 

IMG_0489.pdf

The powdery blue is the actual vivianite. Under the powder is (usually) a paper thin layer of tusk surface that has mineralized with the vivianite. The trick is to expose that mineralized surface without going through it to the ivory below. The mineralized ivory will be a much darker blue than the vivianite powder. In the photo I included earlier in this thread you can see the difference at the base of the tusk. Inside the base you can see the lighter blue vivianite that was not removed from that area.

[Ptychodus04]

That looks like a nice project. I would use some medium to thick cyanoacrylate (super glue) on this one. The thicker glue will help to fill the internal voids and cracks. The higher viscosity glues do not have an instant bond so you will have to support the joint. I like to glue in stages and the wrap the section up with rubber bands to hold it together. It's a slow process but works well.

[JohnBrewer]

5 hours ago, Ptychodus04 said:

That looks like a nice project.

Yeah, not too many pieces too deal with eh Kris  

[Ptychodus04]

41 minutes ago, JohnBrewer said:

Yeah, not too many pieces too deal with eh Kris  

 

Those are ones that only show up in my dreams.

[AlaskaNick]

Im about 8 months late to this conversation but I have a small tusk that I want to restore (never done it before- or anything like it)- plot twist, it’s split lengthwise down the middle... another user on this site has been super helpful in trying to impart some of his expertise. Question- how does cyanoacrylate differ from PVA B-15 in terms of using it as a glue? 

 

Also, it has been recommended to me to use apoxie sculpt to fill the larger voids/cracks, but I think I’m going to have to use some extremely strong glue to get these pieces back together. 

 

Last, I’m hoping for a very smooth, glossy finish, but I’m not sure at which point in the process to start sanding. Sand, and then apply a PVA B-15 finishing coat? 

 

Any help is is greatly appreciated!

[Ptychodus04]

As a glue, PVA/Paraloid/Butvar all provide a very strong and an ever so slightly flexible bond with a very slow set time. Cyanoacrylate provides a strong but brittle bond. It doesn’t take much lateral movement to break it and it sets very quickly.

 

If you want to polish your tusk, follow the directions in the other post but after you fill the cracks with Apoxie Sculpt (a very strong material), sand the tusk starting with 250 grit and working up to 1000 grit. Then polish on a wheel with rouge.