LordWampa Posted July 24, 2023 Share Posted July 24, 2023 (edited) Hello @pachy-pleuro-whatnot-odon I will tag you here again because I have seen in other posts that you have some knowledge about this. In this big mosasaur jaw plate, as they normally do in Oued Zem, it's covered in white glue. I want to try to take out the white glue layer from the bones without touching the matrix. I have started doing it with a scalpel. But obviously is a lot of work, i have seen in another posts the recommendation of using acetone. If i use a cloth with acetone and just use brush the bones carefully will this work? Is there another way? And it's a good idea to remove the glue even if it's just from the bone? Should I try to apply another varnish like paraloid b-72? O I can leave the bone without anything? Edited July 24, 2023 by LordWampa Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted July 24, 2023 Share Posted July 24, 2023 In the past I've used both the scalpel and acetone methods. The scalpel is quite okay, especially if the glue layer is peeling already (which can sometimes be done even without using a scalpel), However, you do run the risk of bone flaking and adhering to the glue layer once you peel it off, so it may not always be the best method around. Acetone works well with most glues, as it does with the white glue they use in Morocco. You would need quite a bit of cloth (of cotton facial pads) to clean the specimen, though, as once you wipe the glue off of the specimen, you should change the piece of cloth used, so that you're not just spreading the same glue around again. I also don't know how things would work if you were to use coloured cloth, as I've always used cotton pads myself. I find that they don't leave a lot of fibres behind. And when they do, those are easily cleaned away by another pad drenched in acetone. Keep in mind that cleaning the specimen will make it look completely white, by the way, as the pigmentation you're seeing right now is, in fact, due to impurities on the brush that was used to apply the varnish. As to whether you'd need to apply a new varnish or not... That depends on the quality of the bone underneath. However, I have treated the pieces I've restored or cleaned up with an acrylic crafts seal (also soluble in acetone) to prevent accidental damage to the bone surface. The replacement mineral in the phosphates seems to be gypsum (or something close to it), which makes these specimens inherently fragile. Some surface-level varnish would protect against more superficial types of damage as well as flaking. 1 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
LordWampa Posted July 25, 2023 Author Share Posted July 25, 2023 Thanks again for this long answer. I have to say that the color is one of this things that make me doubt as I like the typical yellow to white color of mosasaur fossils from oued zem. But at some points the glue is so thick and yellow that you can't see the texture of the bone. So maybe I don't do a full cleaning, I will try to go to the spots with too much glue and spread it a little bit. By the way, is there a reason to use general acrylic crafts seal insted the typical paraloid that is normally used with fossils? Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted July 25, 2023 Share Posted July 25, 2023 2 hours ago, LordWampa said: Thanks again for this long answer. No worries! Always glad to help 2 hours ago, LordWampa said: I have to say that the color is one of this things that make me doubt as I like the typical yellow to white color of mosasaur fossils from oued zem. But at some points the glue is so thick and yellow that you can't see the texture of the bone. So maybe I don't do a full cleaning, I will try to go to the spots with too much glue and spread it a little bit. I know what you mean. For some reason the bits of yellow and brown give it a more authentic look, right? Although I do like it when these fossils are completely white too, makes for a beautiful contrast. But, sure, start removing a bit of the thicker layers of glue and see how that works out for you 2 hours ago, LordWampa said: By the way, is there a reason to use general acrylic crafts seal insted the typical paraloid that is normally used with fossils? Two reasons, really. First one is that I want as experienced with Paraloid at that point to mix it up to a varnish consistency, so that I was afraid of how a more liquid mix would affect the bones (e.g., some fossils and rocks will become temporarily greatly weakened by application of too liquid a consolidant and may even bloat/deform). Whereas in the other, I had quite some experience with the particular crafts seal I used, which I knew wouldn't penetrate too deeply and would thereby form a perfect surface varnish in much the same way as the white glue the Moroccans use - i.e., the result would be very similar to that of other Moroccan pieces in my collection. The main advantage of Paraloid, in this case, would be the proven long-term maintainability of it, whereas the crafts seal is currently unknown, though I've got good expectations of it, since people using it basically also use it for conservation, if only for art projects... 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
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