Properly preserving two pieces of Mammoth tusk

[Mr. Go]

Hi all!

 

I recently bought these two pieces of mammoth tusk that have been fished up from the North Sea during the 80ties.

 

The current owner inherited them and didn't know if they had been desalinized.

 

The larger one was badly preserved and coated with some sort lacquer with all kinds of ugly blobs.

I did 3 passes of 400 grit water resistant sandpaper on both of them which removed all the old gunk from the larger one and smoothed both of the tusks out nicely.

As you can see in the pictures they both have some cracks, the larger one gets up to about 5 mm at most and the other one is about 1.5 mm. on the smaller one.

 

I've got a couple of questions.

 

- Should i still desalinize both tusks as I'm not sure this has ever happened.

- should i clamp the larger piece to get rid of the cracks before stabilizing it ( the ducktape was a temp. option until i find out how to approach this)

- I've read on here i should use paraloid B72 and acetone to preserve it properly.

    How much of both would i need is one kg of Paraloid b72 enough and 1 liter of acetone ( or do i need 5, bout 20 percent more than a gallon.)

- is it possible to fill in the cracks with a lower dilution of Paraloid and Acetone?

 

Thank you for your time!

[RuMert]

If it survived from the 80's and looks ok, why do anything else?

[fossilus]

I would definitely consolidate. I suspect these are still very fragile.

I would use 5% initially, and a thicker solution to fill cracks after the initial treatment had dried.

You will probably need to remove the duck tape first (but I've never treated with duck tape on).

I know some put on hose clamps to squeeze the cracks before treatment.

[Fossildude19]

@Ptychodus04

[pachy-pleuro-whatnot-odon]

Hello, and welcome to the forum from a fellow Dutchman!

 

So many tough questions, none of them easy to respond too...

 

48 minutes ago, Mr. Go said:

The current owner inherited them and didn't know if they had been desalinized.

 

It's hard to say whether the pieces were originally desalinated or not. But in general, I'd assume that someone knowledgable enough to know to coat these pieces with some kind of consolidant would've probably also been smart enough to desalinate them before. All the same, the pieces having received some kind of coating makes it difficult to see the effects that capillary action from the tusks' internal salinity would've had on the specimens - typically visible as flaking either on the outside, but also inside, of the tusk.

 

48 minutes ago, Mr. Go said:

The larger one was badly preserved and coated with some sort lacquer with all kinds of ugly blobs.

 

This is probably some kind of white glue that was used in copious amounts to inundate the specimen as fully as possible, without giving sufficient time for the air to escape. This will result in the formation of air bubbles trapped in surface glue.

 

48 minutes ago, Mr. Go said:

I did 3 passes of 400 grit water resistant sandpaper on both of them which removed all the old gunk from the larger one and smoothed both of the tusks out nicely.

As you can see in the pictures they both have some cracks, the larger one gets up to about 5 mm at most and the other one is about 1.5 mm. on the smaller one.

 

I don't know if I would've used sand-paper on these specimens myself, as in addition to the glue, you'll also have inadvertently removed some of the dentine making up the tusk itself. I'd rather have tried rubbing the glue off with acetone. The upside to this technique is that you can achieve better penetration of glue removal, while the downside is that if you apply too much acetone at a time this may moisten and thereby weaken your specimen. If your aim is displayability rather than (just) maintaining the scientific integrity of the piece, however, I don't think there's much of an issue.

 

1 hour ago, Mr. Go said:

Should i still desalinize both tusks as I'm not sure this has ever happened.

 

Generally it's always dangerous to reinundate fossils that have been out of the water for a long time, such as these specimens. Consolidants may dissolve, certain types of which can moreover leave white staining, as can old glue joints. This may greatly affect the integrity of the specimens and may even break them apart. On the other hand, even if a piece has already been desalinated, it never hurts to repeat the treatment (just make sure you use water with a low mineral content, such as demineralised water, if only for the last couple of baths).

 

Thus, if you feel the tusks are solid enough, you could try to fully immerse them by first putting them in a bath and slowly poring water into the basin in a part facing away from them. This ensures there's minimal wave action to disturb the specimens, while giving air inside of them sufficient time to escape. I'd, moreover, process them one by one, so that you don't put both specimens at risk simultaneously (always a good idea when trying out new preservational techniques). Don't let the tusks dry between baths, but do let them dry slowly once desalination is complete.

 

1 hour ago, Mr. Go said:

should i clamp the larger piece to get rid of the cracks before stabilizing it ( the ducktape was a temp. option until i find out how to approach this)

 

That's up to you and on how you want the pieces to end up looking. Trying to close the cracks removes the natural look of the specimens and increases internal tension, so is not something I'd personally do. Much rather, I'd look into filling the gaps using a gap-filler, if they're really a concern. In any case, I wouldn't apply clamps before desalination so as to expose a greater surface area from which the water can extract salt, but also wouldn't do so when applying the consolidant, the latter, though, having more to do with the clamps getting in the way rather than anything else...

 

1 hour ago, Mr. Go said:

I've read on here i should use paraloid B72 and acetone to preserve it properly.

 

I've used Dahler and Rowney's Decoupage Medium (arts and crafts seal) in the past to consolidate mammoth tusks. This product is an acrylic varnish that's rather thin and therefore has reasonable penetration into fossil bone and wood specimens (it gets sucked up). While not one of the traditional consolidants, I've found that it maintains its transparency quite well over the years and is partially reversible by virtue of creating a film that can easily be scraped and pulled off after drying. I haven't tried to see if acetone can be used to remove it, however (though I assume it can), nor whether the same is true for pieces that have been fully inundated.

 

These days, however, I would probably also go for Paraloid B72, which is available for purchase ready-made in certain shops (including one in the Netherlands). This ready-made 10% solution has quite good penetration and has equally good qualities as a varnish, so might be all you need. Otherwise you'd use a 2-5% solution for consolidation and a 5-10% solution to seal the surface.

 

I'd say there's no question as to whether you should consolidate the specimens, rather on how. Ideally, you'd inundate your specimens in Paraloid in order for the solution to access every area of the piece. Since your tusks are quite large and thus would require large amount of Paraloid-solution, even if you could find a suitable container, I'm not quite sure whether full inundation would be an option. Instead, you could apply multiple surface coatings with a brush, letting the Paraloid be sucked in between applications, or simply pour Paraloid over the specimen. The problem with these last two solutions is that they'll create a mess and you need to consider how you're going to ensure that the Paraloid doesn't glue your specimens to the underlying surface (putting a small container underneath the specimen to be treated and ensuring the bottom of this basin doesn't dry out before you're done with your consolidation work might be a good option).

 

1 hour ago, Mr. Go said:

How much of both would i need is one kg of Paraloid b72 enough and 1 liter of acetone ( or do i need 5, bout 20 percent more than a gallon.)

 

This again depends on the percentage-dilution of Paraloid you intend to use, as well as the size of your specimen, the way you intend to apply the Paraloid, the size of the basin you might be using and the exact formula used to mix up the Paraloid. The formula I've been taught uses 10% of the volume in Paraloid for a 10% solution, whereas others recommend using a weight-volume. That is, what I've been taught is to fill up the equivalent of 50 ml with Paraloid pellets for a 500 ml total solution, whereas others would recommend to use 50 grams instead. However, a volume of 50 ml Paraloid pallets weighs in at about 25 grams. I think this should suffice for you to do your own calculations, since I can't estimate how much you'd need.

 

1 hour ago, Mr. Go said:

is it possible to fill in the cracks with a lower dilution of Paraloid and Acetone?

 

It certainly would be possible. But, again, it depends on what exactly you want to do. If you intend to glue the cracks together then I'd recommend using a CA-glue, which would be much stronger than the Paraloid (these types of glue also come in varying thicknesses for different purposes). However, if doing so, make sure to do that after consolidation, since the Paraloid-solution contains acetone that will also undo your CA-glue. If your point is to just fill up small gaps, you can again do this with CA-glue, but could also do this using a less diluted Paraloid. Keep in mind, however, that this method will not work if the gap is too big, as the filler will not be able to dry quick enough, while in all cases the gaps will still remain visible as veins of transparent plastic. If your aim is neither to glue the cracks together nor simply consolidate the piece by gap-filling, but instead is targetted at creating a more attractive display piece, I'd recommend looking at other types of commercial gap-filler, such a plaster of Paris, wall-filler, car body filler, or stone filler, and then applying some acrylic paints on top of that to match the colours of the fossil tusks themselves (be sure to paint a wider area than the gap you're filling to get the most natural looking transition). If possible, it may be useful to get a two-component filler, as you'll be able to mix this up at the exact thickness you need for the work you intend to do.

 

@sjaak, however, has more experience dealing with material coming from the North Sea, so may have some useful pointers to add as well. In any case, I hope the above is of use to you.

[Ptychodus04]

Remove the duct tap immediately. You don't want the glue to adhere to the tusk or 2 things will happen: glue will be left behind which you will need to clean off, and/or the tape will pull the top layer off the tusk.

 

I wouldn't address any possible salt concerns at this point as the process would likely destroy the specimen. Once dry, fossil ivory reacts poorly when water is introduced. If there was salt present, I would expect to see crystals that have formed on the surface.

 

I use a 2.5% solution of Paraloid B72 for consolidation. This is 1 part Paraloid to 50 parts acetone measured by weight. 100 grams of Paraloid will mix with 7 liters of acetone at this ratio (if I converted everything correctly. You could go with 50 grams and 3 liters for your solution. Find a non-acetone reactive dish that is slightly larger that your piece, place the specimen into the tray and pour your solution over the specimen. With luck, it will fully submerge. If it does, let it sit until it stops bubbling. Remove and lay on a piece of corrugated cardboard to dry. Don't worry if it sticks, you can wipe with acetone to remove the stuck cardboard.

 

If it doesn't submerge fully, paint solution onto the top and rotate the specimen in the solution periodically. Then, do the drying process.

 

Fill the cracks, if desired, with Apoxie Sculpt. It comes in many colors and can be mixed to get a close match to the color of your tusk. It is worked just like modeling clay and you have a couple hours of working time before it sets up. It can be sanded when set.

 

The only variable is the leftover "lacquer" or whatever was on the piece. It may react with the acetone. I would test a section with straight acetone prior to consolidation to see if anything goes awry.

 

 

[pachy-pleuro-whatnot-odon]

4 minutes ago, Ptychodus04 said:

Remove the duct tap immediately. You don't want the glue to adhere to the tusk or 2 things will happen: glue will be left behind which you will need to clean off, and/or the tape will pull the top layer off the tusk.

 

Completely agree, and forgot to mention. From my experience with mammoth ivory, applying duct tape to such inherently frail specimens isn't a good idea. Be very careful when removing the tape, however, as damage may already have been done, and careful removal may minimize further damage.

 

7 minutes ago, Ptychodus04 said:

I wouldn't address any possible salt concerns at this point as the process would likely destroy the specimen. Once dry, fossil ivory reacts poorly when water is introduced. If there was salt present, I would expect to see crystals that have formed on the surface.

 

Here I don't agree. I've treated plenty of archaeological and fossilised pieces where salt deposits were initially hidden from view, but would only be drawn to the surface after a while. Seeing as the specimens had some kind of varnish applied that has now been removed, it's quite possible that there may not have been any traces of salt that will only be pulled to the surface now that air moisture can actually access the piece. It's also very well possible that the salt crystals will never be visible, as was the case with my tusks sections, which, all the same, started gradually breaking up due to internal salt deposits, until I desalinated them.

 

That having been said, it's probably safe to wait wit desalination until salt crystals do form, as one round of them coming to the surface is not likely to change too much from the current condition the specimens are in. If you decide to go for this approach, however, you won't be able to apply any consolidant just yet and may need to wait for up to a year or longer for noticeable crystals to form in a Dutch climate.

 

13 minutes ago, Ptychodus04 said:

The only variable is the leftover "lacquer" or whatever was on the piece. It may react with the acetone. I would test a section with straight acetone prior to consolidation to see if anything goes awry.

 

Also a true and good warning

[Ptychodus04]

21 minutes ago, pachy-pleuro-whatnot-odon said:

I've treated plenty of archaeological and fossilised pieces where salt deposits were initially hidden from view, but would only be drawn to the surface after a while.

 

great to know!

[Harry Pristis]

Forget the salt question.  You'll have to trust that the finder has done his work while the tusk was still damp from the sea.  Never re-wet a dried tusk with water. 

Remove the duct tape gently, using acetone applied sparingly (I'd use a syringe) to weaken the tape adhesive.

Soak the tusk in acetone/plastic consolidant.  (Don't use a decoupage or acrylic varnish -- use a consolidant used by museums after long experience.) 

Let the tusk dry thoroughly. 

THEN you can deal with esthetic issues like cleaning the surface or filling the cracks with epoxy putty.

[pachy-pleuro-whatnot-odon]

42 minutes ago, Harry Pristis said:

Forget the salt question.  You'll have to trust that the finder has done his work while the tusk was still damp from the sea.  Never re-wet a dried tusk with water. 

 

Just wanted to add here that I have done this in the past with great success. I had two pieces of tusk that I had bought for little money on a Queens Day flea market that started crumbling with time. I figured salt in the specimens was the likely culprit. And rather than having the pieces crumble to bits, I decided to take the risk and desalinate them - which went surprisingly well...

 

This is also where I used the decoupage medium, something I at that point generally applied to my personal finds back then (mostly Holzmaden ammonites), but something I've since switched away from after having gained more experience with Paraloid.

 

That having been said, I expect, as stated, that OP's tusks have already been desalinated. And in any case there's more risk involved. As such, I agree that not desalinating them at this point may be the wisest course of action.

[sjaak]

1 hour ago, Harry Pristis said:

Forget the salt question.  You'll have to trust that the finder has done his work while the tusk was still damp from the sea.  Never re-wet a dried tusk with water. 

Remove the duct tape gently, using acetone applied sparingly (I'd use a syringe) to weaken the tape adhesive.

Soak the tusk in acetone/plastic consolidant.  (Don't use a decoupage or acrylic varnish -- use a consolidant used by museums after long experience.) 

Let the tusk dry thoroughly. 

THEN you can deal with esthetic issues like cleaning the surface or filling the cracks with epoxy putty.

I agree with this advice. Rewetting a dried tusk can cause bubbles that can destroy the tusk. You can use a brush to apply the consolidant to prevent this problem when soaking.

 

 

[Harry Pristis]

19 minutes ago, sjaak said:

I agree with this advice. Rewetting a dried tusk can cause bubbles that can destroy the tusk. You can use a brush to apply the consolidant to prevent this problem when soaking.

 

 

The osteodentine swells and shrinks in a wet - dry cycle.  When the ivory shrinks, it tends to delaminate and crack.  Bubbles of air have nothing to do with the destruction.  Immerse, flood, soak the ivory with consolidant!  

I've never liked the idea of applying consolidant with a brush -- that is too much like painting.  I grant that it may be a semantical distaste I feel.  But, painting is associated with applying a surface coating, and coating is not what we should do with consolidant.  When I can't immerse a fossil in consolidant, I use a turkey baster to flood the specimen.  

[Ptychodus04]

If you take no advise other than one, listen to @Harry Pristis

 

2 hours ago, Harry Pristis said:

it may be a semantical distaste

 

This doesn't invalidate your feelings.

[Mr. Go]

Thank you for all the responses, Im amazed by amount and quality of all the posts in such a short time window!

 

20 hours ago, RuMert said:

If it survived from the 80's and looks ok, why do anything else?

 

The inside of the tusks is falling apart; i forgot to mention that in my opening post, esp. the larger tusk is already missing quite a bid of the side that wasnt in the skull when the animal was alive.

 

19 hours ago, fossilus said:

I would definitely consolidate. I suspect these are still very fragile.

I would use 5% initially, and a thicker solution to fill cracks after the initial treatment had dried.

You will probably need to remove the duck tape first (but I've never treated with duck tape on).

I know some put on hose clamps to squeeze the cracks before treatment.

 

thank you i will remove the ducktape as other responses mentioned this isnt a proper way to go.

 

18 hours ago, pachy-pleuro-whatnot-odon said:

Hello, and welcome to the forum from a fellow Dutchman!

 

Thank you! ive started a bit of obsession after finding large amounts of fossil pieces at the zandmotor!

 

18 hours ago, pachy-pleuro-whatnot-odon said:

typically visible as flaking either on the outside, but also inside, of the tusk.

 

the pieces are indeed flaking, the smaller one a little bit and the large one has lost quite a bit already on the left side of the piece

18 hours ago, pachy-pleuro-whatnot-odon said:

formation of air bubbles trapped in surface glue.

its def not woodglue but brownish lacquer that formed blobs like you would see if you lacquer a table dont properly smooth it out before drying.

 

18 hours ago, pachy-pleuro-whatnot-odon said:

I don't think there's much of an issue.

the will both just be used for display purposes, from my understanding it's almost impossible to properly date pieces from the north sea bed without knowledge of the exact positioin if came from ( i might be wrong though )

 

18 hours ago, pachy-pleuro-whatnot-odon said:

Seeing as the specimens had some kind of varnish applied that has now been removed, it's quite possible that there may not have been any traces of salt that will only be pulled to the surface now that air moisture can actually access the piece. It's also very well possible that the salt crystals will never be visible, as was the case with my tusks sections, which, all the same, started gradually breaking up due to internal salt deposits, until I desalinated them.

 

 

The larger one had been varnished , the smaller one wasnt. I suspect they've started delaminating due to the salt amount that's still stored in them at this point, although i might be wrong. How big are the pieces you have?

 

18 hours ago, pachy-pleuro-whatnot-odon said:

In any case, I wouldn't apply clamps before desalination so as to expose a greater surface area from which the water can extract salt, but also wouldn't do so when applying the consolidant, the latter, though, having more to do with the clamps getting in the way rather than anything else...

thank you i think i will forego clamping the pieces in this instance!

 

18 hours ago, pachy-pleuro-whatnot-odon said:

however, has more experience dealing with material coming from the North Sea, so may have some useful pointers to add as well. In any case, I hope the above is of use to you.

it most certainly is! I will look into all the options you have mentioned and make a choice most fitting to the situation.

 

17 hours ago, Harry Pristis said:

Let the tusk dry thoroughly. 

THEN you can deal with esthetic issues like cleaning the surface or filling the cracks with epoxy putty.

thank you harry for your response, i think i will follow this route as it has been mentioned before, at the very least i will immediately remove the ducktape ( and hope no damage has been done already.

 

19 hours ago, pachy-pleuro-whatnot-odon said:

That is, what I've been taught is to fill up the equivalent of 50 ml with Paraloid pellets for a 500 ml total solution, whereas others would recommend to use 50 grams instead. However, a volume of 50 ml Paraloid pallets weighs in at about 25 grams. I think this should suffice for you to do your own calculations, since I can't estimate how much you'd need.

this is very enlighting , thank you so much!

 

19 hours ago, Ptychodus04 said:

I wouldn't address any possible salt concerns at this point as the process would likely destroy the specimen. Once dry, fossil ivory reacts poorly when water is introduced. If there was salt present, I would expect to see crystals that have formed on the surface.

 

They dont have any white crystals on the surface so I suspect they may have been indeed desalanized in the past.

 

19 hours ago, Ptychodus04 said:

You could go with 50 grams and 3 liters for your solution. Find a non-acetone reactive dish that is slightly larger that your piece, place the specimen into the tray and pour your solution over the specimen. With luck, it will fully submerge.

this i very helpfull, thank you so much! 

 

19 hours ago, Ptychodus04 said:

rotate the specimen in the solution periodically.

how long should this be ; hours or minutes or maybe days?

 

15 hours ago, Harry Pristis said:

  When the ivory shrinks, it tends to delaminate and crack. 

i think thas may have been the issue, as there is delamination on the inside of the larger piece (quite bad i reckon, a least a quarter of the whole length has been "hollowed out".

 

15 hours ago, Harry Pristis said:

've never liked the idea of applying consolidant with a brush -- that is too much like painting. 

i've read the same on here in other posts regarding the subject; so i think fully submerging is the way to go, as it has also been mentioned in the other responses 

 

 

[pachy-pleuro-whatnot-odon]

4 minutes ago, Mr. Go said:

How big are the pieces you have?

 

Unfortunately, as mammals aren't really my thing, I sold on my pieces on, a couple of years ago already. They were about 30cm each, if I remember correctly...

 

5 minutes ago, Mr. Go said:

how long should this be ; hours or minutes or maybe days?

 

Generally, at least with smaller fossils, this would be until air bubbles stop coming out of the fossil. On small fossils this will typically be in under a minute, but I have no idea how much time this would take on bigger specimens, as I've never treated anything bigger than 5 cm this way. In order to help the air get out of the fossil, ensure no water remains trapped, and increase penetration of the Paraloid, it's often recommended to heat the specimen up before inundation. This can be done in bright - and above all warm - sunlight (may be not the smartest idea for ancient ivory, as sunlight is known to interact with and bleach modern ivory - possible the same goes for ancient pieces), under a heat lamp, or, what I do, in an oven set to 150 degrees Celcius (although, again, I don't know if this would work well on ivory).

 

Two notes of warning to be added when fully inundating a specimen in Paraloid are that 1) the acetone in the Paraloid will dissolve glue that has been used on the specimen previous, with more glue being dissolved the longer you keep the specimen in the Paraloid-solution (this may affect old restorations) and 2) depending on the porosity of the material inundated in the Paraloid, the fossil may initially become weaker as it sucks up the Paraloid - kind of like a wet kitchen towel also looses its strength. Once dry it will of course regain its strength, but be careful removing the specimen from the Paraloid when you're put it in there fore a long time.

 

Another warning to add is that acetone is a toxic and highly flammable chemical that you should avoid breathing in or touching. So, work in a well-ventilated space, cover your basin with Paraloid while you let it work into the fossil, if taking a long time, and place and lift your specimen in and out of the solution using something like thongs or another tool.

 

17 minutes ago, Mr. Go said:

i've read the same on here in other posts regarding the subject; so i think fully submerging is the way to go, as it has also been mentioned in the other responses

 

Fully submerging the specimen in a Paraloid-solution would definitely be best, but is not always possible. As such, using something like a pipette or turkey baster, or simply pouring Paraloid out over the specimen are good alternatives. I think using a brush should be used as a third fall-back option, but then mostly to really dab the Paraloid on. Whenever I use a brush, I always make sure it's very wet before applying the Paraloid, in a way using it like a pipette, just as a way to apply large amounts of Paraloid locally.

 

16 hours ago, Harry Pristis said:

When the ivory shrinks, it tends to delaminate and crack.

 

25 minutes ago, Mr. Go said:

the pieces are indeed flaking, the smaller one a little bit and the large one has lost quite a bit already on the left side of the piece

 

I think it's important to make the distinction between delamination, cracking and flaking. Delamination and cracking are indeed the consequence of shrinkage in the ivory, which probably is mostly related to changes in the environment the specimens are stored in. Flaking, on the other hand, which is superficial, is - at least insofar as I believe - the result of salt operating on the surface of the tusks and can and should preferably be stopped by desalination.

 

27 minutes ago, Mr. Go said:

its def not woodglue but brownish lacquer that formed blobs like you would see if you lacquer a table dont properly smooth it out before drying.

 

There are certain older alternatives to Paraloid which I believe dry up into a brown colour, such as Vinac, I believe. Older home-made recipes, such as glue diluted in acetone (1 Velpon 5 acetone used to be a very popular formula in the Netherlands when I grew up in the late 80's and early 90's) may also have discoloured over time. However, it may also be worse than that, and the original owner may have simply got some DIY-varnish when they noticed the specimen beginning to flake. This would mean they both used the wrong type of consolidant and didn't desalinate...

 

I, for example, recently had to deal with a collection of fossils that had been coated in paraffin wax that, while it had protected the fossils for close to 15 years, made them look dark, hid details and made them feel waxy to the tooth. What's worse, though, is that you could feel that the matrix and fossils below the wax coating were very light and frail. I thus set about to remove all the paraffin and re-treat the specimens using Paraloid, so they should be able to last for at least 15 years more... Best practices, of course, change through time - as do those that are less than best...

 

36 minutes ago, Mr. Go said:

They dont have any white crystals on the surface so I suspect they may have been indeed desalanized in the past.

 

Just wanted to point out one last time that not seeing white crystals on the surface of a specimen doesn't mean it doesn't contain salt. Such crystals are often very frail and will easily crumble, often leaving a powdery or dusty trace around the object. As such, you can easily brush them off, after which it may take several months for new crystals to form - but only if the piece isn't handled in the meantime. If it is, any crystals formed are likely to fall off again, without too much of a trace. As such, it can be very difficult to establish whether a specimen contains salt or not, with crystals being but the symptoms of a badly affected piece. To me, the superficial flaking you mentioned suggests that the tusks have not been desalinated...

[Ptychodus04]

1 hour ago, pachy-pleuro-whatnot-odon said:

acetone is a toxic and highly flammable chemical

Acetone is not considered toxic any more. It is listed as an irritant. Some people are more sensitive than others. I wear a respirator with a VOC vapor canister when dealing with large qualities or longer uses of it since I deal with the stuff on a more regular basis than most hobby collectors. That being said, it is considered to be relatively harmless to humans with normal use.

 

Wearing gloves and having good ventilation are really the only safety measures most people need.

[sjaak]

On 11/17/2021 at 7:26 PM, Harry Pristis said:

The osteodentine swells and shrinks in a wet - dry cycle.  When the ivory shrinks, it tends to delaminate and crack.  Bubbles of air have nothing to do with the destruction.  Immerse, flood, soak the ivory with consolidant!  

I've never liked the idea of applying consolidant with a brush -- that is too much like painting.  I grant that it may be a semantical distaste I feel.  But, painting is associated with applying a surface coating, and coating is not what we should do with consolidant.  When I can't immerse a fossil in consolidant, I use a turkey baster to flood the specimen.  

True, but it happened to me that dry ivory or pieces of teeth fell apart when putting it in water or aceton/ paraloid. Slowly adding the consolidant or using a brush until the bone or ivory seems absorbed worked with me.

[Mr. Go]

On 11/18/2021 at 11:56 AM, pachy-pleuro-whatnot-odon said:

Unfortunately, as mammals aren't really my thing, I sold on my pieces on, a couple of years ago already. They were about 30cm each, if I remember correctly

what is your main collection if i may ask? I really do appreciate all your help immensely.

 

On 11/18/2021 at 11:56 AM, pachy-pleuro-whatnot-odon said:

Generally, at least with smaller fossils, this would be until air bubbles stop coming out of the fossil. On small fossils this will typically be in under a minute, but I have no idea how much time this would take on bigger specimens, as I've never treated anything bigger than 5 cm this way. In order to help the air get out of the fossil, ensure no water remains trapped, and increase penetration of the Paraloid, it's often recommended to heat the specimen up before inundation.

 I will do exactly as you described, my guess would be it would take quite a long time. the pieces are quite heavy (both in excess of 5kg so i reckon it wouldnt be done in a few minutes.

 

On 11/18/2021 at 11:56 AM, pachy-pleuro-whatnot-odon said:

ind of like a wet kitchen towel also looses its strength. Once dry it will of course regain its strength, but be careful removing the specimen from the Paraloid when you're put it in there fore a long time.

 

I think this is a very important thing to notice, i hadnt thought of it. I think i would take them out of the solution very carefully regardless but it cant hurt to be warned beforehand.

Does all the acetone have to vapor off before you take the fossil out of the solution or is it purely there to make the solution able to penetrate all the microscopic caveties?

 

On 11/18/2021 at 11:56 AM, pachy-pleuro-whatnot-odon said:

 

I think it's important to make the distinction between delamination, cracking and flaking. Delamination and cracking are indeed the consequence of shrinkage in the ivory

 

I think i used to wrong term earlier to describe the flaking; its def. delamination thats going on not flaking, am i correct in assuming this is the result of incorrect storage and lack of preservative on the inside? And not the buildup of salt crystals i had thought earlier.

 

On 11/18/2021 at 11:56 AM, pachy-pleuro-whatnot-odon said:

such as glue diluted in acetone (1 Velpon 5 acetone used to be a very popular formula in the Netherlands when I grew up in the late 80's and early 90's

it would be either that or a varnish. either way i took off the ducktape and some of the remains of it come with it which was a happy sight to behold. I used sticker remover the remove any traces if the tape and some remains of whatever had been put on it also came off. So it must have been something that acetone removed.

 

On 11/18/2021 at 1:52 PM, Ptychodus04 said:

Acetone is not considered toxic any more. It is listed as an irritant. Some people are more sensitive than others.

thank you for this, i will conserve the pieces outside with gloves on, and a mask if i can find them with the current situation in the world.

 

On 11/19/2021 at 11:30 PM, sjaak said:

True, but it happened to me that dry ivory or pieces of teeth fell apart when putting it in water or aceton/ paraloid. Slowly adding the consolidant or using a brush until the bone or ivory seems absorbed worked with me.

or you talking about mammoth mollars, ive read that they are notoriously hard to preserve 

[pachy-pleuro-whatnot-odon]

5 hours ago, Mr. Go said:

what is your main collection if i may ask? I really do appreciate all your help immensely.

 

My main interest lies with the marine reptiles of the Mesozoic, and especially the bigger clades, such as ichthyosaurs, pl(es)iosaurs and mosasaurs. I don't often get a chance to search myself, but have managed to build a nice collection all the same: generally, apart from mosasaurs, Europe is a great location for marine reptiles

 

And not to worry, glad to be of help

 

5 hours ago, Mr. Go said:

 I will do exactly as you described, my guess would be it would take quite a long time. the pieces are quite heavy (both in excess of 5kg so i reckon it wouldnt be done in a few minutes.

 

I think this is a very important thing to notice, i hadnt thought of it. I think i would take them out of the solution very carefully regardless but it cant hurt to be warned beforehand.

Does all the acetone have to vapor off before you take the fossil out of the solution or is it purely there to make the solution able to penetrate all the microscopic caveties?

 

The full immersion is so as to get as complete a penetration as possible, which may be difficult to achieve by other means. Hence that if full immersion is not possible, it's recommended to liberally pour Paraloid over the specimen: this is the best way to mimic full immersion. So it's certainly not necessary for all the acetone to vapour off. In fact, this may leave you with issues beyond the fact that it's probably not a good idea to inhale such quantities of acetone, since traces of Paraloid are likely to stick your container to your specimen, leaving traces of it's treatment. This is one of the reasons why it's necessary to turn the specimen over during treatment, so that all sides of the piece get equal exposure to the Paraloid, thus can equally be penetrated. It's also why you need to flip your specimen over during drying, so that it doesn't stick to the cardboard on which it lies (I find that, at least for smaller specimens, sturdy but porous cardboard works very well to help your specimens dry - though you need to flip them occasionally). If, however, you do accidentally end up with traces where the Paraloid appears to have been pulled off of the specimen, simple re-immersion in Paraloid or a touch-up with acetone would resolve this. You can also touch the spot up with a brush, as the acetone in the Paraloid will dissolve the "stain", while simultaneously closing any hole that it may have created.

 

Please do take care with the specimen becoming weaker the longer it's exposed, as it can be very tricky to detect this, though may be very detrimental to the fossil. It won't happen that fast, but you do need to keep an eye on it.

 

5 hours ago, Mr. Go said:

I think i used to wrong term earlier to describe the flaking; its def. delamination thats going on not flaking, am i correct in assuming this is the result of incorrect storage and lack of preservative on the inside? And not the buildup of salt crystals i had thought earlier.

 

I'm not entirely sure, to be honest. But I think that if you're indeed talking about delamination, then the likelihood of this being the result of salt inside the specimen is less, as there are other good explanations for these symptoms...

 

5 hours ago, Mr. Go said:

it would be either that or a varnish. either way i took off the ducktape and some of the remains of it come with it which was a happy sight to behold. I used sticker remover the remove any traces if the tape and some remains of whatever had been put on it also came off. So it must have been something that acetone removed.

 

Glad to hear the ducktape is removed and could be removed so cleanly. However, for future reference I'd recommend against the use of sticker remover on any fossil. This is because the active component in these products is - as far as I'm aware, at least - still acetone, but with impurities added to adjust its secondary properties. As these impurities are unknown, the effects they'd have on your fossil would also be unknown. Acetone is a known and tried product and does the exact same job sticker remover does without these concerns.