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Metophioceras or two....


Terry Dactyll

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Thanks guys.... I will get back onto it shortly.... Just catching up with the gardening as it feels like the end of winter now....last night hurricane Katey and power cuts !

This ones around 16 inch across....

Cheers Steve... And Welcome if your a New Member... :)

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:drool:

"Let us therefore follow after the things which make for peace, and things wherewith one may edify another."
-Romans 14:19

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I done some more work on the shell.... I defined the mouth opening better.... It has a thin calcite vein running 45 degrees through this area and no matter how careful you are smoothing with the pen you always get a step starting with the vein acting as a weak fault in the rock.... The simple answer is to use a rotary tool and this smoothes the vein and the rock at the same speed producing an acceptable finish and no obvious weakness or flaw....

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Cheers Steve... And Welcome if your a New Member... :)

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Thanks Guys.... I never went to church either Roger....I broke through on the outer whorl... it is intact so I'm pleased about that... Theres some serious digging to be done yet though I reckon another 20 hours plus to just get the edges visible in the rock... Its a tough chunk....

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Cheers Steve... And Welcome if your a New Member... :)

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Roger...Thanks.... I agree its certainly got potential.... I done another couple of hours tonight.... I will keep you posted....

Cheers Steve... And Welcome if your a New Member... :)

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Theres about another 5 hours gone into this shell.... Mainly doing the mining operation of a couple of inch of very hard matrix coming off above the lower edge of the ammonite....The rocks that hard I broke my SQ air chisel tip so while I am awaiting a repair to be done to the tip I am sorta roughing it.... just digging with a HD pen.... Reminds me of the good old days.... :D

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Cheers Steve... And Welcome if your a New Member... :)

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Roger... Yep.... Its one of the hardest chunks I have dealt with... But were getting there....

Cheers Steve... And Welcome if your a New Member... :)

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I had a look at the big Metophioceras I been working on and noticed I had left a 'flat spot' where it joins to the rock at the base...It just didnt look right asthetically, like a tyre with a puncture so I took more rock off until the base followed the curve of the ammonite and exposed the full width... and got a few more ribs out as well heading towards the centre now.... It took a while, 2 hours vanished in no time....

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Cheers Steve... And Welcome if your a New Member... :)

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Thanks Guys.... Hopefully it will be worth the effort in the end....

Cheers Steve... And Welcome if your a New Member... :)

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Its starting to make some sort of sense now after another few hours work although the limestone rock has changed from consistent and predictable to hardening up and having hundreds of natural fracture planes breaking into small triangular chunks where it wants if you apply too much pressure so to combat this I have really had to turn the speed of the air pen down... this in turn slows the progress of the prep right down too...

Thats how it goes... I can see glimpses of the next whorl where I have caught the calcite so on wards towards the centre.... ' when I get chance ' :D

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Cheers Steve... And Welcome if your a New Member... :)

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  • 2 weeks later...

Roger... Your not kidding there....

I decided its time to cut a base on the rock to make it free standing displayed on the matrix... How I like em.... This isnt as simple as it sounds.... The first few I ever done I got the old stil saw out and lined it up and thought thats about right... Cut the base and hey presto there it is... looking good... Then one day I ended up with a shell that was leaning forward and looked terrible by just guessing the angles and it took hours to put right as there wasnt enough rock left to cut, but I had to grind it to change the level...lesson learned the hard way...

These days I put the ammonite on a flat surface and prop the rock up on steel wedges and get it looking just as I want it, with the mouth in the orientation it looks best etc... Then using a masonry nail and a wooden latt of the right thickness, taking into account what thickness I'm cutting off, I scribe the cut line across the front and around the sides to get the angle correct and a level base....Only then will I commit to cutting it....

Heres the shell with the cut base and bits and bobs I used to achieve this....

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I managed a couple more hours chasing towards the centre... Its looking pretty compacted but ok so far.... The successive whorls are now pretty level which shows the side of the shell I am working on was face down in the sediment...Burial, compaction and crushing during fossilisation has pushed the centre downwards and whilst looking at that face ' outwards ', so it is a little distorted....The shell is a little 'eliptical ' too which again is pretty common with shells from these layers... Noticeable in the Lyme ammonite pavement shells to I was once told by a well known Lyme commercial prepper and collector....

Nothing to get concerned about though this is common with these big shells...Sometimes the very centres are crushed and fragmented which is where restoration is required... as a percentage the restoration in comparison to the rest of the fossil surface area its usually less than 5%...

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Cheers Steve... And Welcome if your a New Member... :)

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John Hannes Callomon ?....

Cheers Steve... And Welcome if your a New Member... :)

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Steve...I know what you mean about trimming for a base. I had similar problems at the beginning with not lining the stone up properly and having to recut. I've got it down to a fine art now, though, like you. Your Meto looks to be coming along fine now. Should be a good one when all is said and done. Yes, I suppose she's referring to JH. I guess she wanted to offer one of his articles.

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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