How To Glue Concretions Back Together For Prepping

[J-n-Nay]

Hi,

I am new to fossil prepping.

I have some crab containing concretions that I would like to prep.

What adhesive do you use to glue the conecretions back together?

What are the steps?

Thank you in advance for your time and assistance,

J

[Ludwigia]

I find that super glue works just fine, but maybe someone else has found an even better product. The important thing is that it's thin enough not to leave any cracks and nevertheless strong enough to hold up to torture.

Edited November 10, 2014 by Ludwigia

[Raggedy Man]

I also use super glue, but you have to be Extremely PRECISE when setting it. Zero margin for error if you catch my drift ..

Paul

[Doctor Mud]

I used a two part epoxy resin to glue a conc. I am working on. When using larger quantities of super glue you might have more time to work, but I've found myself regretting using super glue on some repairs as it doesn't give you time to work and get the fit just right, like Paul said.

The thing I'm not sure on yet is whether you should apply adhesive to the entire concretion, or avoid the bits you know will be exposed.

I've seen videos online showing concretion repair from start to finish (can't remember the exact source - he was an English chap) and he applied epoxy adhesive to the whole thing since the adhesive could be prepped off. Don't know if superglue would make it harder to prep rock off crab shell though.

I've just put together my first conc. so I'm still in the learning curve too.

Good luck - look forward to seeing pics of your results

[Ludwigia]

The guys are of course right about superglue. You have to try your fit beforehand and be absolutely certain that the pieces fit snuggly together and know exactly how to set them together before you apply the glue.

[RJB]

When I glue back concs I use a thicker viscosity super glue that is more like a thick syrup than the normal watery super glue. This thicker stuff also gives you much more time to 'play' with the pieces and once you are satisfied I then use a clamp and get it fairly tight and wait 24 hours or more before I go on the prep attack. Oh, I use Star Bond out of Los Angles. they are half the price of paleobond.

RB

[Ptychodus04]

I also use a high viscosity cyanoacrylate. My preferrence is Paleo Bond 1500 CPS. It gets in all the right places and provides a good working time. I don't use epoxy for fossil preparation as I have had to prep the stuff off specimens after the glue broke down and the specimen fell apart... It's not pretty.

[J-n-Nay]

Hi,

Thank you everyone for the information. It is very helpful.

We will post photos as we get started. The prep lab should be up an running this week!!

Thanks again!

[funfordds]

It's interesting to see what everyone else uses. I use crazyglue which tends to be a little watery. If I was gluing 2 sections of matrix that contain a trilobite, I want to be sure to cover the areas below the bug (ventral side) more so than the matrix above the bug (dorsal side). I find the matrix easier to prep away when there is less superglue in that area.

As mentioned above its critical to ensure that the matrix fits as tight as possible, any gaps will cause that area of the fossil to be very thin and likely be destroyed with an air scribe or air abrasive.

To help eliminate gaps I highly recommend using Irwin mini bar clamps. amazon has a 4 pack for 20 bucks, search amazon for "Irwin mini bar clamps 6".

I'm interested in the epoxy method, anyone who uses epoxy, why do you prefer to use it?

thanks!