Kane's Bug Preps

[Kane]

1 hour ago, ober said:

 Very nice Kane. By chance was this prepped with a  CP 8315 air scribe? 90 PSI? I just got one and see it is different from what I expected. It seems it cleans by contact vibration rather than air flow. Right? Now have to get the rest of what I need and start experimenting. Tom

This was just air abrasion using the Paasche AECR.

[Ptychodus04]

3 hours ago, ober said:

 Very nice Kane. By chance was this prepped with a  CP 8315 air scribe? 90 PSI? I just got one and see it is different from what I expected. It seems it cleans by contact vibration rather than air flow. Right? Now have to get the rest of what I need and start experimenting. Tom

 

"Air scribes" use compressed air to drive a stylus (at an extremely high frequency) that removes matrix via percussion. The unit @Kane used employs compressed air to drive a small amount of abrasive to remove matrix by cutting away microscopic bits.

 

Most preparators employ a combination of several different sized scribes and an abrasive system.

[ober]

thank you, tom

[ober]

Hello Kane

 

I want to thank you for the help you’ve offered in getting started in the prep game. I have a small SENCO compressor with water filter in the line which has the virtual of relative quiet, a PN 8315 air scribe and a Paasche AECR. I’m surprised the Paasche has such a modest feel on my finger to the pressure (at 50 psi) but it does work nice. I heated baking soda and sifted, and got some decent preliminary results on U-Dig trilobites from Utah. Even so, the tool got clogged and I was pleased it was easier to clean out than I feared, having had much bad experience in my life taking mechanical things apart and trying to reassemble. I particularly like the fact that I can essentially erase dental tool scratches with the Paasche, at least on slate. I don’t have a permanent set up so this compressor is not bad to move  around. I have a fan over my shoulder which blows the debris away. But I wear a mask anyway. 

 

A question: are other abraisives more effect at the same pressure or do they all work pretty much the same?

 

I haven’t worked as much with the air scribe but it seems to make more aggressive marks on a matrix if I am not careful. At the moment I want to reveal fossils but leave them in the matrix. I can see why people recommend getting additional tips, since I expect at some point the stress will break this one. I want to see how delicately I can use it to break away some shale on embedded trilobite pieces that don’t seccumb to the Paasche. 

 

And then, not so incidentally, I am finding fossils I didn’t really knew I had, but suspected, which opens the door to trying to find out what I now have. More pleasures.

 

Thanks.

 

Tom

 

 

 

 

[Kane]

Hi Tom,

 

Sounds like you've opened a lot of doors! Congratulations.  

 

When it comes to the Paasche clogging, I find sometimes all it needs is a sewing needle in the nozzle to shake things loose unless the clog is farther up the hose. 

 

In terms of abrasives, it very much depends on the material. And even then there are variations on the recipe (pressure + abrasive types). The baking soda crystals are jagged and so imagine microscopic shards hitting and slicing the matrix, whereas dolomite crystals are round but can pack a lot more punch at the same pressure (and risk burning through the fossil). I go with different mixtures of both pending matrix. For instance, Penn Dixie bugs get a 90-10 or 80-20 ratio of baking soda to dolomite. If I'm working tough limestone, dolomite is the way to go as baking soda will hardly cut it. 

 

But when you say the stress on the air scribe, are you pushing? In most cases, the scribe tip should be doing the work, and you do the steering. I'm not sure if you're pushing it too hard.

[Ptychodus04]

15 hours ago, ober said:

are other abraisives more effect at the same pressure or do they all work pretty much the same?

To add to @Kane's comments... Grain structure plays a part as does hardness of the abrasive. Baking soda has a Mohs Scale hardness of 2.5  Dolomite is 3.5-4.0 Most fossil bone is around 3.0-4.0 and inverts vary significantly. The trick with abrasives is to find the delicate balance between efficacy of preparation and damage to the specimen. Harder abrasives can remove more matrix at lower pressures but have a higher propensity to cause damage to the specimen.

 

15 hours ago, ober said:

I expect at some point the stress will break this one

If you're pushing the scribe to the point that you think the stylus might break, back way off. Let the scribe do the work. You should never break a tip with normal use. If it breaks, you had a defective tip, you were pushing too hard, or you got your tip into a hole and simultaneously moved the scribe laterally. The super high precision German scribes tend to shear styli more often due to their close tolerances. They don't handle sloppy use as well. The trade off is that they are exceptionally precise. The long and short of it is that you should dull your stylus through use rather than break it. If the scribe doesn't cut enough with a light pressure against the matrix, you need a bigger scribe or more patience.

[ober]

Thanks for the abrasive insight. I will get my hands on some dolomite and try several blends, And yes, all this is an excercise in patience. As Yoda said, “ be one with the (airbrush) flow.”

[Kane]

Easing myself back into the prep phase after a long hiatus. 

So these Eldredgeops rana rollers come out of the Arkona mudshale. They typically are very fragile, flaky, and delicate. Most of them that are halfway decent and intact are very small, but these rollers are nearly equivalent in size to the rollers at Penn Dixie.

 

This is a soft shale, which sounds good, but it likes to crack as it dries. 

 

Field fresh:

[Kane]

Halfway through. 

 

Only very light scribing, but also pin vise work as well. Most of the heavy lifting is done by the Paasche, and at low pressure. Each one of these is crushed, so the possibility of things getting blown off is high. I had to leave some matrix between a few segments as it was the only thing keeping some of them together. One of them is upside down and already missing a few bits of cephalon shell. 

 

Despite being very careful, an eye did pop off. Miracle of miracles, I found it in the blast box debris within a few seconds, and carefully glued it back on.

 

A crack was also starting to form across the whole rock, so I applied some thin cyanoacrylate to let it seep in the crack, and then abraded the shiny line off.

[Kane]

Pretty much done. I could cut deeper, but the softness of the rock makes that a dubious proposition. Ditto for cutting into the ventral more. Still some baking soda in a few of the cracks, but I'm pleased with it.  

[Fossildude19]

Nice triple, K-man.

[piranha]

16 minutes ago, Kane said:

 

Three of a Kind

  

[FossilDAWG]

Nice trifecta!

Don

[ober]

1 hour ago, Kane said:

Pretty much done. I could cut deeper, but the softness of the rock makes that a dubious proposition. Ditto for cutting into the ventral more. Still some baking soda in a few of the cracks, but I'm pleased with it.  

such patience. nicely done. 

[FossilNerd]

Looks like a pretty good way to ease back into prepping. Well done Kane! 

[Sjfriend]

Cool piece. Love trilobites, and a three-fer is extra cool.

[Ludwigia]

I guess those poor little guys got caught in a landslide. Lucky combo!

[Kane]

Thanks, gents!  

I realized this would have taken a tenth of the time if not for the Paasche, which was having serious flow and other issues. However, I managed to MacGuyver it quite a bit so it now finally works like a charm -- now that this prep was mostly done. But it will be ready to be enlisted for some interesting action to come. 

[Ptychodus04]

1 hour ago, Kane said:

Thanks, gents!  

I realized this would have taken a tenth of the time if not for the Paasche, which was having serious flow and other issues. However, I managed to MacGuyver it quite a bit so it now finally works like a charm -- now that this prep was mostly done. But it will be ready to be enlisted for some interesting action to come. 

Looks good Kane. Well done. Also, I can appreciate the MacGyvering. That’s how I operate on a pretty regular basis.
 

Apparently, this is the week for abrasive issues. We had some serious rain earlier this week and after I refilled the pressure pot on my Vaniman, my system clogged immediately.  Inspection of the soda bag showed a cut... My abrasive had been sucking in all the humidity. So, I cleaned the whole thing out and took my soda inside and baked it in the oven for a while to dry it out, put it in a new container and was ready to go. Yesterday, I was working in a nice little Cockerelites and refilled my pressure pot. I noticed something on the fossil that distracted me and I forgot to put the lid on! Imagine my surprise when I stepped on the foot pedal and about 1/2 a cup of abrasive flew into the air!!!

 

Now, the top of my blast box, the Vaniman, my air filters and desiccant canister, and some of my scribes look like a snow covered Christmas morning. 
 

I’ll clean up tomorrow. This morning I’m off the the Perot to see the Australopithecus sediba and Homo naledi exhibit!

[Kane]

When it rains, it pours (or in your case, snows ). At least all the issues happened at once, for just one unit. For mine, air leak issues had to be mended as I was getting very little of any pressure from my unit (and I hope there is a special ring in Dante's Inferno for whoever invented plumber's tape -- using that is like trying to do surgery with a hand of thumbs!), but then air flow was compromised from the valve to the pen housing's air tube... and that required peeling off the duct tape used to secure it there, and picking out the super glue, trimming both the tube and a bit of the back end housing. adjustment of the valve, (very) slight widening of an air flow hole, etc. I was close to seeing if I could just rebuild the entire unit from available parts. Oh, and the valve lacks a fire button, too, leaving only the sharp stem, so I used a padded fingertip. I would complain, but the unit was simply not meant or designed to do this kind of work. 

 

I still may try to build something better as the mechanism itself is fairly simplistic. Possibly even something with interchangeable heads (like a thin fan spray nozzle for landscaping matrix). 

 

I'm off this morning as well, Kris... although in an effort to get away from hominids past or present, to the Devonian on this unseasonably warm January day.  

[digit]

15 minutes ago, Ptychodus04 said:

Also, I can appreciate the MacGyvering. That’s how I operate on a pretty regular basis.

Really? I didn't know that having a mullet was an important factor in proper fossil preparation?

 

 

The bugs look great, Kane. Now that winter has finally settled in and you have snow in the forecast for this week, I expect we'll nice a nice steady stream of wonderfully prepped specimens.

 

 

Cheers.

 

-Ken

[Ptychodus04]

Very important @digit, very important.

[Kane]

Being down a scribe is slowing my progress. I had another Paleo stylus snap for almost no reason, so will likely be going with German engineering next. I was getting sick of it stalling anyway.

 

I'm currently spending a lot of bench time on Terataspis fragments. As fragments of those are kind of a big deal, I am spending a lot of very careful time going slow and steady. I don't think I've ever spent this much time on a glabella -- and it's still far from done.

 

This is after four hours. There is a tough chert and calcite crust that even high powered dolomite has trouble with. I am not sure if this will be just a glabella or so much more. It is robust. And, no, I am not using a dental tool on this -- just using it for scale. Just about nothing can even scratch this material!

[Kane]

Some zoom-in shots of this asteroid-like glabella to show some of its finer microsculpture. I have not yet tidied up the surface, focusing more on peeling it back to find the contours. I cannot just scribe freely at this point because I am unsure of its orientation. Terataspis glabellas are mostly spherical, so it is not possible yet to determine which face is the front or back, or even side. There is not a lot of visual material in the literature to assist in this prep.

[Kane]

And just to give a sense of what I mean by the sphere: