How to work with crosscut mammoth tusk without it falling apart so easily

OK It won't dry too fast on me if I use activator? I just have to be quick after I spray the activator on then glue them together quickly before it dries?
 
Do not spray the activator on the CA and put them together. It starts to set instantly.

What you do is one of two things:
1) Apply the CA to one surface and spray the activator on the oter surface. Put them together and clamp with moderate pressure (NOT hard).
2) Apply the CA and put both pieces together. Clamp lightly. Spray te activator around the perimeter to activate the CA from all sides.

Amazon sells all the CA types. Every knife supplier also sells them. Places like Hobby Lobby, Woodcraft, and most woodworking suppliers usually have a large selection.
I have been using the Mercury Adhesives CA in thin, medium, and thick ...plus the required matching Mercury Adhesives activator. I have found it to be excellent for knife handle work and ivories. I get it from my local Woodcraft, but it is available from many other places.
The four piece starter set is less than $30 on Amazon and will last a long time.

Tips:
Use a backing piece that is larger than the mammoth. That makes it easier to get the piece in place without careful alignment.
Either micarta or G-10 will work as a backing. Most all knife suppliers carry thin G-10 and some thin micarta. Check out Alpha.
Use medium or thick CA for wide joints like laminating. It has slower cure time.
Use thin CA for penetrating to stabilize things. It will penetrate grain and the tiniest cracks. Several coats are recommended. Sand the surface between coats.
Let CA dry overnight between coats. Just because it says "5-10 seconds cure time" doesn't mean it is fully hardened.
Cut, sand, shape with fresh abrasives and do NOT let it get hot. Heat will make the mammoth crack as well as weaken the CA bond.
 
OK mi was going to order a medium star bond CA glue I don't have stores near me like that and I found thin G-10 liner that will work it's 1mm or 1.5mm thick because the inlays I make are only about 3mm thick so thanks alot for your time I tried it without a backer and it fell apart on me like nothing and I waisted 105$ so it occurred to me it must need a backing thanks so much I can't wait try it again and accomplish something this time
 
Jeff Whitaker 1987 said:
What exactly do you mean use a bigger piece of g10 than the mammoth? Thicker than the mammoth?
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I believe he's talking about the outline, don't try to cut the backing piece to match the tusk exactly before gluing them together. Make the liner bigger so you don't have to spend time tying to get them to match exactly.
 
weo said:
I believe he's talking about the outline, don't try to cut the backing piece to match the tusk exactly before gluing them together. Make the liner bigger so you don't have to spend time tying to get them to match exactly.
Click to expand...
Makes total sense great idea
 
Pretty much any brand CA will work. Star Bond is OK. I think the Mercury Adhesives is a bit better. Like I said, you can order it from Amazon and have it tomorrow.

Don't try and cut down the mammoth until it is backed. A trick with a thicker piece of mammoth is to flatten both sides and apply the stabilizing thin CA. Place it on waxed paper while doing this. Once the resin is cured, sand the two sides flat. Then, put a backing piece on both sides. Once cured you can carefully saw down the middle and get two backed pieces safely. If te backing is too thick, sand/grind it down thinner, but 1mm is the thinnest I would recommend.

Notes -
A hand hacksaw with a 24-tooth blade works quite well. Go slow and don't let it get hot.
On small pieces I need to cut up, I take a 3X3X3" block of wood and attach the piece I am cutting to one side with double sided foam tape. I hold te block while cutting. This works very well. After the cut is made I use a sharp knife to slice through the tape, or just slice the wood off at the end and grind away the thin piece of wood and tape.
I use a fresh 24-tooth blade on my SWAG metal cutting bandsaw on smaller pieces. While I and others with experience use a large wood-cutting bandsaw, I do not recommend using a regular wood bandsaw unless you have a fine-tooth blade and the necessary skills, as the mammoth can grab the teeth on most bandsaw blades ... and pull your fingers into the blade as well as destroy the ivory.

Two big tips on cutting up mammoth slices from a tusk section are:
Stabilizing to keep it from falling apart - If it has clearly discernable separation rings, cut it into thick segments (3-4" thick) and set on end on waxed paper. Flood the end with CA and let sit overnight (don't use accelerator). Turn the piece over the next day and do the other side. Then repeat for several day, using the accelerator each time.

Cutting the sections up evenly and safely - Glue the tusk section on a flat board that is considerably larger than the tusk section (I use 5-minute epoxy). This gives you a firm and safe assembly to cut up. Then, slice up the board and ivory together on the bandsaw. This keeps the tusk from rolling or grabbing the blade. When cutting scales, I use the same basic method with the blocks glued to the board and running them through the bandsaw to make equal thickness slices
 
Just a thought here; if it crumbles and falls apart that easily is it really something you want on a knife handle? Sounds like if you just dropped it from a six inch height it'd shatter whether you have a backing on it or not.

Eric
 
That's what everyone wants these days is the exotics so if I want to make money and have custom orders for Inlays I need to learn mammoth you know how people are and I screw my inlays on so with a backing I don't think it would break if dropped if it's glued properly and all of my customers don't even use they're knives anyway lol they just collect and stare at them
 
Ugh... Mammoth. I've purchased a fair amount of both cast and stabilized mammoth from several vendors. I've also done a good deal of experimenting of my own. The biggest thing is that it absolutely hates heat. If you overheat it in the slightest while grinding, it's going to become very crumbly and fall apart on you. It doesn't take much heat for this to happen either. If it feels more than slightly warm to the touch while grinding, you got it too hot. You also can't dip it in water, or used compressed air to cool it. You've gotta go really slow, and let it air cool any time it warms up a bit.

You also need to be pretty careful when using a backer. I've had 1/8" slabs of cast mammoth ivory bend like a banana after gluing them to 1/8" G10. The exothermic reaction from glue can be pretty intense. You can prevent this by gluing the liner to the knife first.

I recommend using silicon carbide belts in particular when grinding mammoth. Silicon carbide belts are highly friable and break down/expose new abrasive without too much pressure. Aluminum oxide heats up too much, and ceramic requires too much pressure imo.

These days I typically recommend using mammoth ivory in it's natural form, but crosscut tusk can make that difficult. For crosscut, I recommend stabilizing AND casting the material. It's a pain in the butt, but it's the only way I've really found to get much durability out of crosscut mammoth.

First the material is cast in it's larger form to help hold it together. Then it's cut into slabs .2" - .3" thick and sent to K&G for stabilizing. They use a thinner resin for mammoth ivory than the stuff they use for wood. After stabilizing, the material will have shrunk a bit, and there may be some separation of the dentin. This is when you cast it again (I like to use black dyed resin). The durability at this point will be highly dependent on the resin you choose to use for final casting.

It's a hassle, but it seems to make for fairly durable cross cut mammoth tusk.
 
Thanks Brian, I figured you would chime in with some casting info.
My concern is that his mammoth may be either low grade and/or dredged up from the sea floor in the North Sea. These are really crumbly.
Most of what I cut up for use is pretty solid, with some "rings".
 
Fixall said:
Ugh... Mammoth. I've purchased a fair amount of both cast and stabilized mammoth from several vendors. I've also done a good deal of experimenting of my own. The biggest thing is that it absolutely hates heat. If you overheat it in the slightest while grinding, it's going to become very crumbly and fall apart on you. It doesn't take much heat for this to happen either. If it feels more than slightly warm to the touch while grinding, you got it too hot. You also can't dip it in water, or used compressed air to cool it. You've gotta go really slow, and let it air cool any time it warms up a bit.

You also need to be pretty careful when using a backer. I've had 1/8" slabs of cast mammoth ivory bend like a banana after gluing them to 1/8" G10. The exothermic reaction from glue can be pretty intense. You can prevent this by gluing the liner to the knife first.

I recommend using silicon carbide belts in particular when grinding mammoth. Silicon carbide belts are highly friable and break down/expose new abrasive without too much pressure. Aluminum oxide heats up too much, and ceramic requires too much pressure imo.

These days I typically recommend using mammoth ivory in it's natural form, but crosscut tusk can make that difficult. For crosscut, I recommend stabilizing AND casting the material. It's a pain in the butt, but it's the only way I've really found to get much durability out of crosscut mammoth.

First the material is cast in it's larger form to help hold it together. Then it's cut into slabs .2" - .3" thick and sent to K&G for stabilizing. They use a thinner resin for mammoth ivory than the stuff they use for wood. After stabilizing, the material will have shrunk a bit, and there may be some separation of the dentin. This is when you cast it again (I like to use black dyed resin). The durability at this point will be highly dependent on the resin you choose to use for final casting.

It's a hassle, but it seems to make for fairly durable cross cut mammoth tusk.
Click to expand...
Can't dip in water? Wow didn't know that... Even if stabilized & cast? How come? Wouldn't that make for a knife handle on a blade that could never be exposed to water only?
 
Stabilized and cast will help, but mammoth is very hygroscopic. The water it absorbs can cause cracking and deterioration.
The North Sea stuff has been on the bottom of the ocean for millennia, and may look pretty, but it will start to fall apart as it dries out. The price is low, but so is the quality and usefulness.
 
REK Knives said:
Can't dip in water? Wow didn't know that... Even if stabilized & cast? How come? Wouldn't that make for a knife handle on a blade that could never be exposed to water only?
Click to expand...

That's just while grinding. Cycling the material from hot to cold quickly causes the material to become super brittle.

Once it's ground and finished, it should handle water fairly well. Similar to horn. It will have some expanding and contraction depending on the environment/humidity, but it shouldn't be too bad.
 
Fixall said:
That's just while grinding. Cycling the material from hot to cold quickly causes the material to become super brittle.

Once it's ground and finished, it should handle water fairly well. Similar to horn. It will have some expanding and contraction depending on the environment/humidity, but it shouldn't be too bad.
Click to expand...
Ahhh so if I grind on a water cooled belt that's soaking wet it shouldn't be an issue?
 
I don't grind mammoth wet.
I'll let Brian tell you about his thoughts on wet grinding mammoth. He does a lot, too.
 
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REK Knives said:
Ahhh so if I grind on a water cooled belt that's soaking wet it shouldn't be an issue?
Click to expand...

That should be just fine. Should really help with keeping the smell down in shop too. :)

I use a 10” diamond wet tile saw for cutting these days and the water hasn’t been an issue.
 
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