Big Ammonite Repair Adhesive

[Mantelliceras]

Hello everyone!

I managed to bring home this crazy guy, the problem is that it was so big it broke in pieces when extracting it. I've been using "Loctite Super Glue 3" (ethyl cyanoacrylate) for repairing my fossils until now and it worked pretty well. However, this one might be too heavy I'm afraid it wont be enough to keep the pieces together and it can be dangerous (since the whole fossil probably weights over 70 lbs).

There are also some cracks I would like to fill, I heard a technique where you ground some matrix rock to dust and then use that powder to make a glue that has the exact same colour of the fossil, anyone knows about it?.

To summarise: what is the best adhesive for heavy rocks? and, is there a way to fill the cracks so it won't look like it's broken?

 

Thank you very much for your help.

 

Here goes the picture of the fossil:

Best regards,

[Kane]

I'll page our resident ammonite doctor, @Ludwigia for his advice, as I know he has pretty much fixed and prepped the most challenging ammos.

[Ludwigia]

@Mantelliceras I use a product from UHU called MAX REPAIR Universal Transparent for glueing heavy fossils back together. As far as making stonemeal, grind the matrix down to a fine powder and add a few drops of clear laquer to it until it has a mealy consistency, then apply. You can also use a product called Apoxie Sculpt Modelling Compound for filling cracks and larger gaps. Your ammonite looks like it should turn out quite nicely by the way. Can you tell us what species it is and its stratigraphical position?

[Mantelliceras]

@Ludwigia Thanks for your answer, I will take a look at those products and consider preparing stonemeal. 

This ammonite was salvaged from a quarry before being destroyed and turned to dust. It was a race against time and took me 3 days to get it out. I dont know the exact species yet, it's from the Late Jurassic (prob oxfordian) of Valencia (Spain) and among the species that I have found in the same place so far there's ammonites (mostly Perisphinctes, Holcophylloceras, Lytoceras, Taramelliceras, Epipeltoceras, Sowerbyceras, Gregoryceras), belemnites and some echinoids. I've never found one this big, do you have any idea what species it might be?

 

Thanks again.
Best regards,

[Ludwigia]

@Mantelliceras Looks like a perisphinctid, but I'd have to see it after prep to tell for sure.

[George Hockey]

Hi forum, 

I am in a very similar predicament to @Mantelliceras, except its not as big and the cracks are larger (less snug and well fitting when placed together).

Thanks so much @Ludwigia for the useful advise. Could I ask a tried and tested clear lacquer brand you trust and your method of selecting the right stone for the matrix and also how you grind it up. Sorry for all the questions, it belongs to my father who suffers from dementia and had somehow managed to Bury it in the garden a few years ago. It is a great que to trigger good memories for him and want him to restore this for him. Any help would be greatly appreciated. 

[George Hockey]

[Ludwigia]

@George Hockey It doesn't matter which brand of lacquer as long as it's clear. You could save the matrix which is left over when you prepare the ammonite. The best thing of course is to use any matrix which surrounded the fossil, but that's not possible in your case since you didn't remove it from the outcrop yourself. Anyway, just wrap the pieces of matrix in an old cloth and bang away at it with a hammer until it's dustified. Of course you should do that in some kind of container so that nothing gets lost. If you don't have enough matrix to fill the gaps, then either select some stones with the same color as the fossil and treat them the same way as above, or you can resort to either plaster of paris or the Apoxie Sculpt I mentioned above to fill the gaps. You may have to balance out the color with water paint at the end of the process.

[George Hockey]

Thank you so much I will try to scrape away the excess stone from the outside of the ammonite and use that as matrix. Thank you for your time, help and knowledge, good day sir

[Ludwigia]

2 hours ago, George Hockey said:

Thank you so much I will try to scrape away the excess stone from the outside of the ammonite and use that as matrix. Thank you for your time, help and knowledge, good day sir

You're very welcome

[George Hockey]

Hi sorry to ask stupid questions, I started trying to scrape some excess rmaterial away from around the fossil last night but the fossil itself is quite soft, only slightly harder than the surrounding material

. and I noticed there was a few tiny scratches that must have made in it. I have looked at various sources online but there are lots of different options and mostly too expensive. I do have a dremmel but it might be a bit risky? . What would you recommend to remove the excess material and expose more of the fossil. Is submerging it in vinegar safe? Thanks again. Any advise greatly appreciated 

[Ludwigia]

All I can suggest is to continue carefully with the dremel and wash it in between to ascertain how the progression is going. Vinegar won't help in this case and may even cause some damage.