Dealing with existing prep work on a Hell Creek dinosaur bone

[TriVeratops]

Hi, I’m new here!

 

So I recently won an auction for what is easily the most charismatic fossil in my small collection: a nearly complete scapula of an adult hadrosaur (edmontosaurus?) from Hell Creek.

 

(with PNSO corythosaurus for scale)

 

I’ve never had a fossil anywhere near as big or fragile as this one, and I’d like to learn how best to take care of it. 

 

It was reassembled and gap-filled/restored with a gray adhesive and a white putty (epoxy?). The putty was concealed with brown acrylic paint. It doesn’t look like there’s any protective coating.  (I’ve asked the seller if they can tell me what products were used for prep. They said they’d look into it.)

 

Most of the middle area here is restored.

 

As sold, the scapula was in two pieces. I’m not inclined to try to reconnect them because (1) the fossil is easier to move in two pieces and (2) it looks like they may not connect properly anyway because a piece of the distal blade didn’t fully lock in during reassembly.

 

The break

 

During shipping, a piece of the glenoid and a small chunk of the distal blade re-broke. 

 

Glenoid piece with gray adhesive

 

Distal blade piece

 

The preparer covered some areas of natural bone with acrylic paint in an attempt to make the restored areas blend in. I would rather the restorations be visually distinct from natural bone and I hate seeing paint on bone, so I tried removing some of the paint with a Q-tip soaked in isopropyl alcohol. That seems to work well without any harm to the bone, as far as I can tell.

 

Restored areas with smeared paint

 

Finally, although most of the fossil seems reasonably sturdy as restored, the crumbly bits at the end of the distal blade are really spongy and fragile and I think a consolidant and/or coating might be desirable. 

 

Crumbly bits and smeared paint

 

I don’t want to attempt anything super complicated, but I’m thinking about doing the following:

 

-Reattach glenoid and distal blade pieces with superglue gel

-Consolidate end of distal blade with low-viscosity superglue or Butvar

-Using rubbing alcohol and cotton swabs, continue to slowly remove acrylic paint smears until it looks “good enough”

-Give the whole thing a protective matte or low-sheen coating (Butvar?)

 

Is any (or all) of the above too risky for a beginner to attempt on a piece like this? Any recommendations, things you would do differently?

[hadrosauridae]

All your planned steps are simple and you shouldnt have any problems.  Use Butvar instead of superlgue to consolidate the end.  Superglue will be perfect to reattach the broken piece.  If it is a tight fit, a thin superglue will work well.  If its not (and I'm guessing from the photo its not) a smooth, clean break, then a thicker gel type super glue will be perfect.  Just remember, you need to hold it in place for a while.  Thick super glues take longer to set, its not instant (as it would be if your fingers got in the mix)  Also, be sure to give it 24 hours to completely cure.  As for paint removal, acetone will work better, but you have be careful because acetone will temporarily soften any superglues used in the initial repair.  You could use a damp cotton ball to briefly wipe away some paint, then give it a while to completely evaporate before wiping again.

 

You fossil is a very nice piece, although I'm confused by the prep work I see.  Someone took the effort to reassemble but then didnt fill the cracks, especially after making the effort to rebuild the missing section.  Then they didnt bother to reassemble and fill the broken center?  Then the paint seems very amateurish. Some aspects look pretty good, then others seem very crude, so its kind of confusing.  But there's no problems with it that you can't finish yourself if you want to take the time to do it.

Edited June 1 by hadrosauridae

[TriVeratops]

Thank you, that’s very good advice! I’ll move forward with care and continue to ask questions. Btw I really appreciate the wealth of information on this forum and I’m doing my best to do my homework so as not to do anything irreversible.

 

You absolutely read my mind about the prep work. I found it really strange too.

[hadrosauridae]

5 hours ago, TriVeratops said:

Thank you, that’s very good advice! I’ll move forward with care and continue to ask questions. Btw I really appreciate the wealth of information on this forum and I’m doing my best to do my homework so as not to do anything irreversible.

 

You absolutely read my mind about the prep work. I found it really strange too.

 

One more tip, dissolve your butvar in denatured alcohol instead of acetone.  All those small pieces you want to consolidate are likely attached with a superglue.  Using an acetone based consolidant could cause those parts to fall apart.

[TriVeratops]

1 hour ago, hadrosauridae said:

 

One more tip, dissolve your butvar in denatured alcohol instead of acetone.  All those small pieces you want to consolidate are likely attached with a superglue.  Using an acetone based consolidant could cause those parts to fall apart.

 

yikes, that’s good to know! Will do.

[Alex S.]

I agree with everything @hadrosauridaesaid and would also suggest you get some paleobond or other epoxy putty and fill in the cracks as that will go a long way for future stability. Lovely fossil and I'd love to see more pictures of it when you finish your prep. Good luck!

[TriVeratops]

1 hour ago, Alex S. said:

I agree with everything @hadrosauridaesaid and would also suggest you get some paleobond or other epoxy putty and fill in the cracks as that will go a long way for future stability. Lovely fossil and I'd love to see more pictures of it when you finish your prep. Good luck!

 

Good suggestion, that would also allow me to retouch some of the more messy areas of gap fill from the previous restoration.

 

I’m also thinking about maybe (later on, after I’ve done the simpler things) restoring the distal end with something like Paleosculp. It looks like very little additional material would be needed, and I feel like this would further strengthen the crumbling pieces. To do that I would need to find some really good visual reference of undamaged edmontosaurus scapulas…there are lots of photos online, but I haven’t found any that focus in on a scapula from all angles. 

[hadrosauridae]

Yeah thats one of the problems with reconstruction. Clear, detailed photos of individual bones from a specific species can be very difficult to find. You'll want to go ahead and get some paleosculp now.  Thats what you should use for the gap fill in all those little breaks.  Choice of color is kind of and personal option, but grey can be nice because 1) it doesnt try to hide that there was missing bone  2) the contrast of real and remodelled can be nice aesthetic.  3) your specimen apparent already had grey epoxy used, so continuing with that would keep uniformity.    My personal choice is color matching for the small crack fills and grey for modelling the missing bone.  But again, theres not really a wrong or right.

 

The best way to fill those tiny cracks is to take a tiny ball of epoxy and roll it out into tiny "strings" and stuff those into the cracks. Use a small scraper tool, or plastic card to remove the excess above the surface, then a damp cloth to remove any residue on the surface.  

[TriVeratops]

Butvar ordered. Got some acetone at the hardware store. Already have denatured alcohol and superglue gel. 

 

I’m thinking about maybe using this Apoxie Sculpt instead of Paleosculp, since I have it on hand. Forum searches indicate that people have used it with success for fossil prep. Looks like it’s a light brown color, which probably won’t match the existing gap fill, but I’m kind of suspecting I’ll want to repaint all the restored areas in a uniform color anyway. Will test, of course, if I decide to try it. If anybody feels strongly I should opt for Paleosculp or another product instead, please let me know, I’m not trying to ruin this beautiful fossil to save a few dollars 😅

 

[Alex S.]

I've used that and it works fine. I prefer the hell creek brown from paleosculpt mainly because I'm a horrible painter. 

[Flx]

Apoxie Sculpt works well.

Actually, I have been using it to repair an Edmontosaurus scapula before. 

[TriVeratops]

6 hours ago, Flx said:

Apoxie Sculpt works well.

Actually, I have been using it to repair an Edmontosaurus scapula before. 

 

Great, good to know!!

 

I’ve started removing some of the paint with acetone. It’s slow going, as I don’t want to soak the bones and run the risk of weakening the adhesive. 

 

I’ve also been looking for visual reference to reconstruct the distal edge. example: the Senckenberg “mummy.” Now if only I could just take a quick trip to Germany and photograph it from every angle.

 

[TriVeratops]

i’m finding it takes forever to remove the paint if I don’t add some mechanical tools. I’ve started rubbing with a swab or cotton ball soaked in acetone, then scraping with a palette knife, then repeating.

 

Im not trying to remove all the paint (not sure if that’s even possible without damaging bone), I just want it to be less obvious. I’m hoping the chaotic patina of the original bone will help camouflage it.

 

One little spot, about 30 minutes of work.

 

Edited June 4 by TriVeratops

[TriVeratops]

Side note: looks like the preparer messed up the epoxy or something, and literally sanded down the surface of the bone in this spot  

 

 

And there’s still some loose matrix on the lower edge of the distal blade. Will have to remove it if I want to restore the edge. 

 

 

 

 

[TriVeratops]

New pal arrived today. Haolonggood edmontosaurus may be a little guy, but it has a better paint job than this scapula.

 

[hadrosauridae]

I think youre doing a great job.  As for those lines on the fossil, those are natural.  The rib I just prepped has them, and I've seen others as well.  A possible explanation is that as it laid in the river, a dino walked through and stepped on it, grinding the sand and rocks across that spot with its foot.   Or, it could be from matrix shift over the eons grinding that spot.  But I like the dino footstep theory.

[Alex S.]

I agree great job keep at it. Better to go slow then have to fix things after the fact.

[TriVeratops]

1 hour ago, hadrosauridae said:

I think youre doing a great job.  As for those lines on the fossil, those are natural.  The rib I just prepped has them, and I've seen others as well.  A possible explanation is that as it laid in the river, a dino walked through and stepped on it, grinding the sand and rocks across that spot with its foot.   Or, it could be from matrix shift over the eons grinding that spot.  But I like the dino footstep theory.

 

I’m relieved that it’s a natural feature!  I  prefer the dino footstep theory too 

 

and thanks y’all, I really want to bring out the beauty of this fossil and I’ll take as long as necessary to do it right!

 

 

[TriVeratops]

There are a couple of spots where the gap fill was sticking out beyond the bone, so I scraped some of it off and found that under the paint it’s pure white and pretty soft. It looks like it’s plaster, not epoxy. I’m wondering if it’s still okay to use epoxy clay for the remaining gap fill? I feel like epoxy would give it more stability. 

 

 

 

 

 

[hadrosauridae]

If thats not epoxy for the gap fills, I wouldnt trust it.  You will think you have a solid fossil when youre done and then it could break under its weight while handling it at some point.  I dont know of any way to test for what was used.  Epoxy should be super hard, you shouldnt be able to carve it down like that.  Thats a frustrating turn of events.  You may have a lot more work ahead of you.  You may have to carve out what you can and then use your epoxy to refill.  

 

Sorry, I forgot to answer your question.  Absolutely use your own epoxy to fill the exist cracks.

 

 

Edited June 9 by hadrosauridae

[TriVeratops]

36 minutes ago, hadrosauridae said:

If thats not epoxy for the gap fills, I wouldnt trust it.  You will think you have a solid fossil when youre done and then it could break under its weight while handling it at some point.  I dont know of any way to test for what was used.  Epoxy should be super hard, you shouldnt be able to carve it down like that.  Thats a frustrating turn of events.  You may have a lot more work ahead of you.  You may have to carve out what you can and then use your epoxy to refill.  

 

Sorry, I forgot to answer your question.  Absolutely use your own epoxy to fill the exist cracks.

 

 

 

yup, that’s what I was afraid of. I’m certain it’s not epoxy, i can scratch it with a fingernail. This is gonna be quite a project 😅

[TriVeratops]

It occurred to me that this was probably not the first time someone has had to remove plaster from an old fossil, so I did some googling and found this. According to this source, oxalic acid, buffered with sodium bicarbonate to neutralize its acidity, will safely react with and soften plaster, allowing for its easy removal without harming fossil bones. I’m tempted to try this on a small area.

 

 

Edited June 10 by TriVeratops

[hadrosauridae]

Looks like a plan going forward!  Start with very limited areas and watch closely.  Start with very dilute acid, you can always go stronger if its not doing enough.  If it works well, make sure you do small portions at a time.  You dont want to soak the whole thing and be left a 100 piece jigsaw puzzle in the bottom of a trough.  Also, I would suspect the reconstruction on the end to be the same material, thats super frustrating.  

[TriVeratops]

43 minutes ago, hadrosauridae said:

Looks like a plan going forward!  Start with very limited areas and watch closely.  Start with very dilute acid, you can always go stronger if its not doing enough.  If it works well, make sure you do small portions at a time.  You dont want to soak the whole thing and be left a 100 piece jigsaw puzzle in the bottom of a trough.  Also, I would suspect the reconstruction on the end to be the same material, thats super frustrating.  

 

good advice! Will proceed with great caution.

[Alex S.]

Thank you for sharing the poster that is very interesting. Keep up the good work I look forward to seeing your next update.