General Question.

[Lmshoemaker]

Greetings, I need help with a problem that has been popping up every so often. When scribing there is a tendency for bits of fossils to flake off on me. These could be trilobite pluera, crinoid ossicles, ect.. Is there any way to prevent this? I try to use a really light touch, but this doesn't always help, and sometimes the parts that flake aren't even the ones I am working near.

[Doctor Mud]

Hi there,

What sort of scribe are you using?

There are many different types of preservation, even from the same site. Sometimes it seems that some flaking is unavoidable, even with a gentle touch. At least this is what I find with crabs. If a bit flakes off you need to get in quick and dab on some superglue with a needle. Once flaking starts it can be hard to stop if you don't glue straight away. You just need to try and avoid the matrix with the glue.

The long term solution could also be to go for air abrasion. Most people that work on trilos and Crinoidea seem to use scribes for bulk removal and abrasion for close in.

Good luck!

[Lmshoemaker]

I have an ARO, unmodded. It is decent, not necessarily a precision tool, but often I can get pretty close, at least where the matrix is a thin film. I really would like to try a microjack at some point, they look pretty sweet. I kind of go by a piece of advice I got from another preparator. He saw what I was doing and said I relied too much on air abrasion and showed me what he does with scribes, and had an eldredgeops worked to where it looked mostly clear of matrix, most of the surface even looked liked it had been air abraded. I've been trying to do that, get as close as possible. Does tweaking the PSI help?

[Doctor Mud]

I think the Aro is like the ME-9100 and you have a control valve on the tool itself so you shouldn't have to adjust the pressure on your compressor.

I've found there it's really hard to be as precise with my ME-9100 as I can with the Microjack. Even turned down the unit vibrates more and there is more lateral wobble on the stylus. The Aro revs at about 30,000 strokes per minute vs 40,000 and up for micro jacks.

I haven't done any air abrasion, but I've started reading up on it. Makes sense that you would want to do as much as possible with the scribe as the air abrader isn't really designed for bulk removal. You would have to use a lot of powder. Seems like it is a balancing act of knowing how close you can get with the scribe to minimise the abrading.

I saw an excellent video online (I wish I could remember where- I'll see if I can find it again) showing scribing with a Microjack and then air abrasion on a nice little trilobite.

[Doctor Mud]

Here it is:

www.gold-bugs.com have series of videos called the fossil preparation series.

In this one you can see he is using the air abrader to remove the thin skin of matrix and a Microjack for close in "bulk" removal.

See how precise a Microjack is and you can here how high it revs. Hardly any lateral vibration.

They are expensive but worth it if you specialise in trilos.

[Lmshoemaker]

Oh yes! I saw this before I got my scribe, never paid any attention to the scribe he was using. I hadn't realized it was a microjack. Yeah, that's pretty much exactly the amount of precision I need. The unfortunate bit is it will be quite a while before I can afford one.

Two more questions. My aro's front end screws on, and while using it the front end unscrews. It didn't do this when I first got it and I don't know what is causing it. I have tried cleaning it, but this doesn't seem to help. I just got it a few months ago so I don't think replacement parts would be necessary. It also sounds quite raspy now. Any idea? I think the problem might be moisture, but I don't have any way to back this, and don't know how moisture would cause this.

Also, any idea how I can get nice smooth surfaces? I can't seem to get a flat surface with it. I get ridges that when I grind them down, only produce another ridge. Any tips?I try to keep my scribe essentially parallel to the surface of the rock, this gets close, but not exactly the desired effect.

[TOM BUCKLEY]

Oh yes! I saw this before I got my scribe, never paid any attention to the scribe he was using. I hadn't realized it was a microjack. Yeah, that's pretty much exactly the amount of precision I need. The unfortunate bit is it will be quite a while before I can afford one.

Two more questions. My aro's front end screws on, and while using it the front end unscrews. It didn't do this when I first got it and I don't know what is causing it. I have tried cleaning it, but this doesn't seem to help. I just got it a few months ago so I don't think replacement parts would be necessary. It also sounds quite raspy now. Any idea? I think the problem might be moisture, but I don't have any way to back this, and don't know how moisture would cause this.

Also, any idea how I can get nice smooth surfaces? I can't seem to get a flat surface with it. I get ridges that when I grind them down, only produce another ridge. Any tips?I try to keep my scribe essentially parallel to the surface of the rock, this gets close, but not exactly the desired effect.

Are you using any oil in the scribe? After each use you should put 1-2 drops of AIR TOOL OIL in the back of the tool where the air hose goes in.

Tom

[Doctor Mud]

Oh yes! I saw this before I got my scribe, never paid any attention to the scribe he was using. I hadn't realized it was a microjack. Yeah, that's pretty much exactly the amount of precision I need. The unfortunate bit is it will be quite a while before I can afford one.

Two more questions. My aro's front end screws on, and while using it the front end unscrews. It didn't do this when I first got it and I don't know what is causing it. I have tried cleaning it, but this doesn't seem to help. I just got it a few months ago so I don't think replacement parts would be necessary. It also sounds quite raspy now. Any idea? I think the problem might be moisture, but I don't have any way to back this, and don't know how moisture would cause this.

Also, any idea how I can get nice smooth surfaces? I can't seem to get a flat surface with it. I get ridges that when I grind them down, only produce another ridge. Any tips?I try to keep my scribe essentially parallel to the surface of the rock, this gets close, but not exactly the desired effect.

Apparently this is a common issue with the Aro - the front end unscrewing, they mention this on the Paleotools website ( the purveyors of Microjacks). Not sure how you would remedy this. Normally I would say lock-tite (thread locking compound) but you need ready access for oiling the parts. I wonder if duct tape would hold it on? I think it's a design flaw - something you shouldn't need to concern yourself with.

Yes my ME-9100 gets "rumbly" and not smooth when it needs a lube. I also suspect that my air is too wet and this blasts the oil out quickly. I put a few drops of oil in the connector end of the hose and around the o-rings, but it doesn't take long for this to work its way out. I'm also on a limited budget, but I think I'll have to look into a air dryer. I'm in the sub-tropics.

In the mean time, I make sure my compressor tank is empty of water and vent off the built in water trap. I see water in the air hose when I disconnect so I know it's probably a problem.!

I should also mention ( and the more experienced preppers could comment) that for me it's a fine line between not enough and too much oil. You don't want oil squirting out the front. I suspect that things will also be better for me when I reduce the moisture in the lines.

Seems like we have followed a similar path. I've noticed that any uneven bumps are really hard to smooth out with a stylus. Any bumps get further emphasised the more you work it unless you have nerves of steel. A flat grinding surface is best or a rotary bit. I use a cheaper Dremel copy to smooth as I found the same thing that the stylus doesn't smooth as well as I would like.

Edited May 28, 2015 by Doctor Mud

[TOM BUCKLEY]

Apparently this is a common issue with the Aro - the front end unscrewing, they mention this on the Paleotools website ( the purveyors of Microjacks). Not sure how you would remedy this. Normally I would say lock-tite (thread locking compound) but you need ready access for oiling the parts. I wonder if duct tape would hold it on? I think it's a design flaw - something you shouldn't need to concern yourself with.

Yes my ME-9100 gets "rumbly" and not smooth when it needs a lube. I also suspect that my air is too wet and this blasts the oil out quickly. I put a few drops of oil in the connector end of the hose and around the o-rings, but it doesn't take long for this to work its way out. I'm also on a limited budget, but I think I'll have to look into a air dryer. I'm in the sub-tropics.

In the mean time, I make sure my compressor tank is empty of water and vent off the built in water trap. I see water in the air hose when I disconnect so I know it's probably a problem.!

I should also mention ( and the more experienced preppers could comment) that for me it's a fine line between not enough and too much oil. You don't want oil squirting out the front. I suspect that things will also be better for me when I reduce the moisture in the lines.

Seems like we have followed a similar path. I've noticed that any uneven bumps are really hard to smooth out with a stylus. Any bumps get further emphasised the more you work it unless you have nerves of steel. A flat grinding surface is best or a rotary bit. I use a cheaper Dremel copy to smooth as I found the same thing that the stylus doesn't smooth as well as I would like.

I believe that PaleoTools has a fix for the loose front end on the Aro. Check out their website.

Tom

[Lmshoemaker]

Apparently this is a common issue with the Aro - the front end unscrewing, they mention this on the Paleotools website ( the purveyors of Microjacks). Not sure how you would remedy this. Normally I would say lock-tite (thread locking compound) but you need ready access for oiling the parts. I wonder if duct tape would hold it on? I think it's a design flaw - something you shouldn't need to concern yourself with.

Yes my ME-9100 gets "rumbly" and not smooth when it needs a lube. I also suspect that my air is too wet and this blasts the oil out quickly. I put a few drops of oil in the connector end of the hose and around the o-rings, but it doesn't take long for this to work its way out. I'm also on a limited budget, but I think I'll have to look into a air dryer. I'm in the sub-tropics.

In the mean time, I make sure my compressor tank is empty of water and vent off the built in water trap. I see water in the air hose when I disconnect so I know it's probably a problem.!

I should also mention ( and the more experienced preppers could comment) that for me it's a fine line between not enough and too much oil. You don't want oil squirting out the front. I suspect that things will also be better for me when I reduce the moisture in the lines.

Seems like we have followed a similar path. I've noticed that any uneven bumps are really hard to smooth out with a stylus. Any bumps get further emphasised the more you work it unless you have nerves of steel. A flat grinding surface is best or a rotary bit. I use a cheaper Dremel copy to smooth as I found the same thing that the stylus doesn't smooth as well as I would like.

Are you using any oil in the scribe? After each use you should put 1-2 drops of AIR TOOL OIL in the back of the tool where the air hose goes in.

Tom

Thanks you two! Solved the unscrewing front end with some teflon tape I had lying around. As for the raspyness, I don't have any oil, so that is probably it. When I can, I shall get some and report back.

[jpc]

For the loose front end, I put an o ring in between it and the main body, and more importantly I wrap the joint in between body and front end with a piece of hockey tape. Works very well. Might be called athletic tape? I personally only oil my air scribes when they get weird, which is not very often. I know some folks who use a drop of oil every day, but I find it is not needed and tends to get splashes of oil on the fossil.

[Ludwigia]

I personally only oil my air scribes when they get weird, which is not very often. I know some folks who use a drop of oil every day, but I find it is not needed and tends to get splashes of oil on the fossil.

Me too. As to getting a flat surface, I usually use a flat-headed scribe attachment to finish off, running it over the bumps back and forth in various directions until I'm satisfied. Then finally a once-over with the air abrader.

Edited May 29, 2015 by Ludwigia

[Ptychodus04]

Thanks you two! Solved the unscrewing front end with some teflon tape I had lying around. As for the raspyness, I don't have any oil, so that is probably it. When I can, I shall get some and report back.

I use 5 drops of oil for every 8-10 hours of use. (after running about a teaspoon of oil through it a couple months ago.) This seems to do pretty well without blowing oil out the end. I have also started to regularly disassemble the air valve and clean it. This helps with the inevitable stalling that you will begin to have. I have had my Aro for 13 years and it has done very well! I keep threatening to get a Micro Jack but my accountant (wife) allocates the monies elsewhere!