How hard is it to do a self prep on a keichousaurus?

[Bone guy]

I've seen people acid prep their keichousaurs and they come out beautiful. I know nothing about acid prepping, so what would I need if I was going to prep my own keichousaurus? Is it as simple as soaking it in chemicals to melt away the rock?

[Raggedy Man]

Check out youtube. Search acid prep keichousaurs. 

[Fossildude19]

@steelhead9 

 

There is much more involved in it. The chemicals used could be hazardous, and you would likely need to do it in a ventilated area with a vacuum hood to remove any fumes.

Air mask, gloves, etc. 

Steelhead9  is a wonderful prepper, and has done a number of Keichousaurs.   

 

 

[Bone guy]

Looks like it's difficult, but I'd love to learn.  I'll have to do some more research.

[Ptychodus04]

Acid prep can go seriously wrong. I've done a fair bit of it using a few different acids depending on the matrix and the desired results. A proper acid prep can take months (sometimes over a year) to complete.

 

The first step is to learn how to properly handle acids and get all the safety equipment.

[Fossil Claw]

I noticed that the prep videos use formic acid.

 

Would muriatic work also or is it too strong?

[jpc]

My guess is that muriatic (hydrochloric) is way too strong for this sort of delicate work.  There is a reason they use formic... it is a weak acid.  Vinegar would certainly be a better substitute, but don;t tell them I said so. 

[steelhead9]

Air abrasives are a better choice for prepping keichousaurs, but is extremely tricky as the bone is not usually too much harder than the matrix. If you go the acid prep route, the two most important things are many applications of dilute acid over quite a period of time and properly protecting the bone with a consolidant before any acid is applied. I have used paleobond penetrant/stabilizer with good results. Acid prep is a lengthy process where one mistake will be disastrous. I ruined my share of keichousaurs using both methods before finding an exact technique that worked well for me. Good luck, you’ll need it, especially on the heads and toes. 

[Fossil Claw]

47 minutes ago, steelhead9 said:

Air abrasives are a better choice for prepping keichousaurs, but is extremely tricky as the bone is not usually too much harder than the matrix. If you go the acid prep route, the two most important things are many applications of dilute acid over quite a period of time and properly protecting the bone with a consolidant before any acid is applied. I have used paleobond penetrant/stabilizer with good results. Acid prep is a lengthy process where one mistake will be disastrous. I ruined my share of keichousaurs using both methods before finding an exact technique that worked well for me. Good luck, you’ll need it, especially on the heads and toes. 

Sounds much harder than it looks.

 

I wonder where I might be able to get some broken fragments to practice on.

[steelhead9]

Broken fragments would be harder to get than good specimens. The Chinese diggers would never bother to keep pieces. In fact, the Hong Kong dealers charge more for unprepared specimens because they know they will be worth much more when properly prepped. Occasionally a poor quality, unprepared keichousaur is offered on THE auction site quite cheaply. Be sure to check the size as these are often babies. If you think adult keichousaurs are hard to prep, try a baby! I will look through my shelves and see if I have any that I ruined, but don’t hold your breath. I will pm you if I find any. 

[Ptychodus04]

18 hours ago, Fossil Claw said:

I noticed that the prep videos use formic acid.

 

Would muriatic work also or is it too strong?

Muriatic acid will quickly dissolve the bones. You want to use 5% formic or acetic acid. You also need to add calcium phosphate as a buffer.

[Fossil Claw]

11 hours ago, steelhead9 said:

Broken fragments would be harder to get than good specimens. The Chinese diggers would never bother to keep pieces. In fact, the Hong Kong dealers charge more for unprepared specimens because they know they will be worth much more when properly prepped. Occasionally a poor quality, unprepared keichousaur is offered on THE auction site quite cheaply. Be sure to check the size as these are often babies. If you think adult keichousaurs are hard to prep, try a baby! I will look through my shelves and see if I have any that I ruined, but don’t hold your breath. I will pm you if I find any. 

Cool. Thanks

[jdiaz55]

On 1/22/2019 at 4:23 PM, steelhead9 said:

Air abrasives are a better choice for prepping keichousaurs, but is extremely tricky as the bone is not usually too much harder than the matrix. If you go the acid prep route, the two most important things are many applications of dilute acid over quite a period of time and properly protecting the bone with a consolidant before any acid is applied. I have used paleobond penetrant/stabilizer with good results. Acid prep is a lengthy process where one mistake will be disastrous. I ruined my share of keichousaurs using both methods before finding an exact technique that worked well for me. Good luck, you’ll need it, especially on the heads and toes. 

How would one properly apply the consolidant before the acid is used? If the acid hasn't been applied yet, wouldn't the matrix still be covering the bone?

 

What is that exact technique of yours, if I may ask? I'm having trouble finding step-by-step processes on the internet, and more vague suggestions or recommendations. 

[Ptychodus04]

16 minutes ago, jdiaz55 said:

How would one properly apply the consolidant before the acid is used? If the acid hasn't been applied yet, wouldn't the matrix still be covering the bone?

 

What is that exact technique of yours, if I may ask? I'm having trouble finding step-by-step processes on the internet, and more vague suggestions or recommendations. 

 

Here's my acid prep technique. It may be different than @steelhead9's method.

 

Dilute acetic or formic acid to 5%. Add 1 tsp calcium phosphate buffer for every quart of acid solution as a buffer. Brush on consolidant to any exposed bones. Submerge in acid, checking progress every few hours at first. When bones begin to appear, or after soaking for 24 hours remove the specimen and soak in clean water for same duration of acid soak. Pat dry. Apply consolidant to any exposed bones. Properly neutralize any active acid in your solution and dispose. Repeat the process until specimen is fully prepped. Once specimen is prepped and completely dry, use acetone to remove excess consolidant from the bone and reapply if needed.

 

Be prepared to spend a good portion of your calendar doing an acid prep. When done right, it is a very slow process.

[jdiaz55]

5 hours ago, Ptychodus04 said:

 

Here's my acid prep technique. It may be different than @steelhead9's method.

 

Dilute acetic or formic acid to 5%. Add 1 tsp calcium phosphate buffer for every quart of acid solution as a buffer. Brush on consolidant to any exposed bones. Submerge in acid, checking progress every few hours at first. When bones begin to appear, or after soaking for 24 hours remove the specimen and soak in clean water for same duration of acid soak. Pat dry. Apply consolidant to any exposed bones. Properly neutralize any active acid in your solution and dispose. Repeat the process until specimen is fully prepped. Once specimen is prepped and completely dry, use acetone to remove excess consolidant from the bone and reapply if needed.

 

Be prepared to spend a good portion of your calendar doing an acid prep. When done right, it is a very slow process.

Awesome, thanks for the info! That's super helpful. Should each subsequent soak be 24 hours long? Like, 24 hours in acid dilute and 24 hours in water in a repeated cycle? And from your experience, how long does the whole process generally take? I have patience!

[Ptychodus04]

57 minutes ago, jdiaz55 said:

Awesome, thanks for the info! That's super helpful. Should each subsequent soak be 24 hours long? Like, 24 hours in acid dilute and 24 hours in water in a repeated cycle? And from your experience, how long does the whole process generally take? I have patience!

This is wholly dependent on how the matrix responds to the acid. I like to do 24 hour cycles but your mileage may vary.

 

I’ve had acid preps take 3 months to complete.

[jdiaz55]

On 2/8/2019 at 8:01 AM, Ptychodus04 said:

 

Here's my acid prep technique. It may be different than @steelhead9's method.

 

Dilute acetic or formic acid to 5%. Add 1 tsp calcium phosphate buffer for every quart of acid solution as a buffer. Brush on consolidant to any exposed bones. Submerge in acid, checking progress every few hours at first. When bones begin to appear, or after soaking for 24 hours remove the specimen and soak in clean water for same duration of acid soak. Pat dry. Apply consolidant to any exposed bones. Properly neutralize any active acid in your solution and dispose. Repeat the process until specimen is fully prepped. Once specimen is prepped and completely dry, use acetone to remove excess consolidant from the bone and reapply if needed.

 

Be prepared to spend a good portion of your calendar doing an acid prep. When done right, it is a very slow process.

Is this calcium phosphate the same as the calcium phosphate powders that people use as supplements? If so, is it wildly different from dicalcium phosphate? I apologize, I know nothing about using buffers! I feel like once my arriving keichousaurus is completed, (however roughly) I'll owe you and @steelhead9 some sort of consultant fee for all the help and info you've given me! 

[Ptychodus04]

5 hours ago, jdiaz55 said:

Is this calcium phosphate the same as the calcium phosphate powders that people use as supplements? If so, is it wildly different from dicalcium phosphate? I apologize, I know nothing about using buffers! I feel like once my arriving keichousaurus is completed, (however roughly) I'll owe you and @steelhead9 some sort of consultant fee for all the help and info you've given me! 

It is the stuff people use as a supplement. The two are not the same but I’m not exactly sure of the differences. Fossil bone contains significant calcium phosphate. Adding it as a buffer blunts the effects of the acid on the bones.

[jdiaz55]

4 hours ago, Ptychodus04 said:

It is the stuff people use as a supplement. The two are not the same but I’m not exactly sure of the differences. Fossil bone contains significant calcium phosphate. Adding it as a buffer blunts the effects of the acid on the bones.

Wonderful, that makes perfect sense! Which concentration of Paraloid consolidant would you use for the keich bones? I see you typically recommend 1:50 for deep penetration or 1:20 for porous bones? (I used 1:50 on that tooth and 1:20 for the verts I did on your recommendation, and they turned out excellent! Thank you!)

 

Should I be worried about using too much consolidant on the first layer of the skeleton before any of the shale has come off? I'm worried about over consolidating (or rather imprecisely applying the consolidant) before it ever gets introduced to the acid. How would I carefully and accurately apply that first layer of consolidant before any of the matrix is actually lifted from the bone?

[Ptychodus04]

15 minutes ago, jdiaz55 said:

Wonderful, that makes perfect sense! Which concentration of Paraloid consolidant would you use for the keich bones? I see you typically recommend 1:50 for deep penetration or 1:20 for porous bones? (I used 1:50 on that tooth and 1:20 for the verts I did on your recommendation, and they turned out excellent! Thank you!)

 

Should I be worried about using too much consolidant on the first layer of the skeleton before any of the shale has come off? I'm worried about over consolidating (or rather imprecisely applying the consolidant) before it ever gets introduced to the acid. How would I carefully and accurately apply that first layer of consolidant before any of the matrix is actually lifted from the bone?

I would use a 1:20 solution. You're not consolidating as much as protecting. Use a small artist's brush to apply the Paraloid to any exposed bones. If there are no exposed bones, there's no need to apply Paraloid before acid prep since there's nothing to protect.