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Yoda

Cracked nodule repair

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Yoda

I am after a bit of help please. 

I have a fish nodule with a crack that has separated. How do I go about repairing it? 

 

I can either attempt this myself. 

What glue/joining agent do I use? 

Is this straight forward? Bearing in mind I have never attempted this before. 

 

I would also be open to having someone knowledgeable do this for me. 

If it doesn't end up costing me a fortune. 

Does anyone in the UK know of someone reliable.

 

I am at work. Will post photos later

 

Thanks 

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Bobby Rico

Hi can we see some pictures please. I would be good  to see how it fits back together. Cheers 

 

sorry I missed the part about you been at work.

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Bobby Rico

The trick with glueing fossil is to use the right amount of glue. To much glue and it can keep the join apart like bricks and mortar. 

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Yoda
13 minutes ago, Bobby Rico said:

The trick with glueing fossil is to use the right amount of glue. To much glue and it can keep the join apart like bricks and mortar. 

What type of glue would you suggest using? 

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Bobby Rico
1 minute ago, Yoda said:

What type of glue would you suggest using? 

I just use a think superglue but other may use more professional products but it also does depend on the project your gluing . When you post pictures I think it will help and there are many very skilled members here that are happy to help. 

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RJB

It really does depend on the crack.   A thin super glue would work for  a hairline type crack, thin super glue has great wicking power  but you would need a thicker viscosity super glue if the crack is a bit wider.  Really need to see a photo?   also, can you clamp the rock back together?  A clamped joint is stronger than a 'non' clamped joint.  

 

RB

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Ptychodus04

The pictures will make all the difference as to how to go about this repair.

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Yoda

So I got someone at home to take some photos.

 

Here is the item in question.

The crack in the middle of the body is the one of concern

If I put (gentle) pressure on either side, the crack on the surface widens. 

 

 

IMG_4775.jpg

IMG_4776.jpg

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steelhead9

I would be concerned about stabilizing all these cracks. It is not particularly difficult. I would use Paleobond pentrant/stabilizer or a similar cyanoacrylate. Apply it into both sides of the cracks. After it dries, apply a thicker cyanoacrylate to strengthen the gaps (Paleobond and Starbond are 2 of the larger distributors of suitable viscosities). Making the cracks disappear would be a bit involved, requiring epoxy putty and paint.

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Ptychodus04
13 minutes ago, steelhead9 said:

I would be concerned about stabilizing all these cracks. It is not particularly difficult. I would use Paleobond pentrant/stabilizer or a similar cyanoacrylate. Apply it into both sides of the cracks. After it dries, apply a thicker cyanoacrylate to strengthen the gaps (Paleobond and Starbond are 2 of the larger distributors of suitable viscosities). Making the cracks disappear would be a bit involved, requiring epoxy putty and paint.

I agree, a low viscosity cyanoacrylate will work here. I would only apply from the front though as a minor over application of the glue to the rear would allow it to run out onto the fish. Paleobond also sells small tips for their bottles to allow precise application. Glue the loose crack first and clamp the piece to put pressure on the joint. a bar clamp works well for these as it is very adjustable. Let it sit for at least 24 hours clamped. If the other cracks are not moving, you can simply add glue without clamping to ensure they don't open up.

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oilshale
29 minutes ago, Ptychodus04 said:

I agree, a low viscosity cyanoacrylate will work here. I would only apply from the front though as a minor over application of the glue to the rear would allow it to run out onto the fish. Paleobond also sells small tips for their bottles to allow precise application. Glue the loose crack first and clamp the piece to put pressure on the joint. a bar clamp works well for these as it is very adjustable. Let it sit for at least 24 hours clamped. If the other cracks are not moving, you can simply add glue without clamping to ensure they don't open up.

 

I agree.

The concretions from Madagascar often show shrinkage cracks that have already formed during fossilisation and can no longer be glued together without a gap.
In Madagascar, a very elastic contact adhesive (similar to "Pattex") is normally used for bonding. The contact adhesive is applied to both halves, the solvent is allowed to flash off and then both halves are pressed together. This adhesive (this method) does not produce good bondings with small gap widths.
 
For fish from Madagascar I normally use a thick cyanoacrylate as suggested by Ptychodus04.
It is important to completely remove the old glue before applying the cyanoacrylate glue. I put the concretion into an acetone bath (there all glues come off and the glue residues can be removed).
 
Nice Coelacanth (Whiteia woodwardi) by the way.
 
Thomas

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steelhead9
2 hours ago, Ptychodus04 said:

I agree, a low viscosity cyanoacrylate will work here. I would only apply from the front though as a minor over application of the glue to the rear would allow it to run out onto the fish. Paleobond also sells small tips for their bottles to allow precise application. Glue the loose crack first and clamp the piece to put pressure on the joint. a bar clamp works well for these as it is very adjustable. Let it sit for at least 24 hours clamped. If the other cracks are not moving, you can simply add glue without clamping to ensure they don't open up.

I agree with most all of this, but I might have some concerns that clamping may cause other cracks to open. I would, as I said, apply to both sides, using ,as Ptychodus04 says, a fine tip applicator to not over apply outside of the crack, especially on the fish side, and have a rag ready to quickly wipe any excess off of the fish surface before the glue dries. Very minor variations and all of the above methods would work fine.

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Ptychodus04
1 hour ago, steelhead9 said:

I agree with most all of this, but I might have some concerns that clamping may cause other cracks to open. I would, as I said, apply to both sides, using ,as Ptychodus04 says, a fine tip applicator to not over apply outside of the crack, especially on the fish side, and have a rag ready to quickly wipe any excess off of the fish surface before the glue dries. Very minor variations and all of the above methods would work fine.

Only light clamping pressure needed. This is just to help hold the joint in place 

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RJB

Ptychodus has given you about the best advise possible and a very nice coelacanth by the way!  Good luck

 

RB

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Bobby Rico
6 minutes ago, RJB said:

Ptychodus has given you about the best advise possible and a very nice coelacanth by the way!  Good luck

 

RB

I agree with RB . The only thing I would add is not rush this Job . Get the right tools and take your time in working out how your going to approach the repair. Lovely fossil the coelacanth is on my bucket list. Good luck and I said your get the right advice here, :dinothumb:

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Yoda

Thanks everyone for the suggestions and advice.

Much appreciated

 

In a few weeks time I am off work for a few days and will have some spare time to attend to this. In the mean time I will look into buying the right type of glue etc. 

 

Instead of using a vice, would I be able to use elastic/rubber bands?

 

@oilshale and @Bobby Rico

When I was a kid at school (many many years ago :rolleyes: ) I did a science project on JLB Smith and his involvement in the rediscovery of the Coelacanth. Ever since then I have been really fascinated by them.  

When I saw this item on offer, I snapped it up. 

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Bobby Rico
34 minutes ago, Yoda said:

 

 

@oilshale and @Bobby Rico

When I was a kid at school (many many years ago :rolleyes: ) I did a science project on JLB Smith and his involvement in the rediscovery of the Coelacanth. Ever since then I have been really fascinated by them.  

When I saw this item on offer, I snapped it up. 

Me too, I also have a “ when I was a kid story”. One winter when the UK had bad snow I was about 7 or 8 years old . At the top of the road was some old people living in bungalows . My Dad and I dug all the paths and walk ways out so they get out if they needed. I also would go and buy bread and milk for them. An old lady I can’t remember her name gave me an old children’s encyclopedia probably from the 1940s it had no photos but illustrations. One of the stories was of the first living coelacanth been discovered in 1938 of the east coast of Africa and named  Latimeria chalumnae. The species was as you said described by Professor J.L.B. Smith in 1939. I was hooked by then. I have not got a specimen but I live in hope . :)

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Yoda

I have a few books on Coelacanths - Old Fourlegs etc. 

 

Have seen a publication - History of the Coelacanth Fishes which I would love to get, but it's a bit expensive 

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Ptychodus04
5 hours ago, Yoda said:

Instead of using a vice, would I be able to use elastic/rubber bands?

 

You can if you can get a tight enough grip on the nodule. I have done this before and large/thick bands work the best. Be judicious with your gluing if doing this as a spot of glue that leaks out under the bands as a bit of a mess to deal with since rubber bands and cyanoacrylate apparently bond using the strong nuclear force.

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Yoda
26 minutes ago, Ptychodus04 said:

You can if you can get a tight enough grip on the nodule. I have done this before and large/thick bands work the best. Be judicious with your gluing if doing this as a spot of glue that leaks out under the bands as a bit of a mess to deal with since rubber bands and cyanoacrylate apparently bond using the strong nuclear force.

OK, thanks. 

 

Was thinking that I may find some similar looking rocks just to practice on. And see how it goes with that first. 

 

Will update once I have done the repair. 

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