Prep Equipment Advice

[bayoubengal]

Hello,

I've reached the stage in my fossil hunting career where I'd like to find something more delicate than a hammer with which to prepare my finds. Thus far I've stuck to smallish fossils, with the largest being whale bones a foot and a half long. More typical prep work for me would be removing matrix from a 1" Echphora. I don't see myself prepping mouse toe bones just yet, so I think a micro jack 2 would be maddening.

I'm looking for an airscribe that can be delicate enough for some reasonably fine prep work, but big enough to remove some matrix when I need to. I was thinking that perhaps the Paleo Aro with the 2" tip would suffice. I'd welcome any recommendations, as well as recs for an air compressor. For the air compressor, I'd be running a max of 3 tools at a time (can't believe I just wrote that, but my kids are digging this hobby thus far).

While I'm at it, what type of magnification devices would y'all recommend? Again, I don't see myself getting into the really small stuff right now. Is a stereo dissecting scope overkill? What about glasses/loupes?

Many thanks for the advice from a grateful noob.

[Malcolmt]

I use the ARO with the stock tip for most of my air scribing. I have 7 scribes of various types , I like the ARO much better than the CP (have 3 CPs, 2 different models). I also have a Seally from England that is very good (the best) for rough bulk matrix removal. I have 2 ARO's and I am thinking of overhauling one of them with the Paleo Tools kit but at this point I have not had anything to prep that the standard ARO is not doing nicely. The two I have are real ARO's not the knock offs, so I do not know how the knock offs would perform. I have a big 60 gallon 200 PSI compressor in the garage,that I run back into the basement. I also have a smaller 5 gallon Porter 165 PSI unit. The smaller unit could not run two scribes at the same time. It can run the ARO by itself but the pump cuts in about every two minutes when the ARO is running at 90 PSI. I run all my scribes at 90 to 100 PSI and have no issue with stalling but I do disassemble them frequently and make sure they are clean and lubricated.There is never a dip in pressure when running the ARO on the large compressor and it rarely cuts in and then only for about 30 seconds to repressurize the 60 gallon tank.

The larger compressor unit will run two scribes at the same time but I have no need to do that. I suspect with any compressor unit that is affordable (<$1000) that you would have issues trying to run 3 scribes at the same time. They would require a combined cubic feet per minute of airflow that is beyound what these home type units are capable of. You would also need a very large tank to provide a buffer to the units so that the compressor is not constantly running and overheating. I do have 7 quick connects in use though that makes going to another tool really easy. You need an air dryer on the main line of some type if you are thinking of moving to any form of abrasion. I have a large desication unit wall mounted that the main air line from the garage comes into. I then split out after that into three lines that go to inline dryers and line splitters with quick adapters. I run a COMCO abrasion unit and a dental cabinet unit as well as the Paasche and a handheld dental unit. I also have a number of high speed dental handpieces that I used to use a lot some time ago but rarely use any more.

Loupes do not work for prepping, you are too close to the fossil to be able to use abrasion or a scribe or really anything. They are for field inspecting only. Any serious prep requires a stereo scope. I use a pair of Olympus zoom scopes on booms. Look for a used bargain on ebay, they can often be found at auction for around $200 for a zoom model in decent shape. I would stick with one of the major players like Nikon, Olympus B&L etc.

I never prepare anything except under the scope. Typically at about 7 times magnification. MAx that I practically ever use is around 20 times but at that point the field of view is too shallow and the light is dim and the vibration of prepping makes it too hard to be in focuse. When I started prepping I first used one of the 3x visor units that went over my head, that worked fine until I moved beyond just prepping with dental tools and a dremel vibrator.

If you have specific questions just ask.

[bayoubengal]

Thanks for the incredibly helpful reply! I suppose I'll tell the kids to share and stick with my original plan of running a single tool at a time. Now to start looking into scopes and (eventually) abrasion...

[Malcolmt]

If I had to guess using an airscribe actually accounts for about 5% of the time I spend on prep. Most of the prep time is with air abrasion or dental tools. I probably spend more time with glues, (cyano, PVA in acetone, plaster , epoxy and modelling putty consolidating the matrix and repairing the fossil than actually air scribing..... Also because of what I tend to collect (things on plates) my diamond tile saw probably gets more work time that the air scribes as well.

As for scopes make sure you invest in a barlow lens. This lens actually reduces the magnification but increases your working distance. You cannot prep if you don't have enough distance between the scope and the fossil to use your tools. I have two a .75 and a .5 barlow. I have 3 widefield oculars (all highpoint) 10, 15 and 20. I find the 20 most useful as I generally use a .5 barlow this gives my Olympus a zoom range of 7x to 20x (Since the scope will zoom continuously from .7 to 4 times) If I want to see a wider field I will pop in the 10x ocular. The 15x ocular is pretty much useless. The 10x are original Olympus that came with the scopes. The 15 x and 20x are chinese knock offs and are very good and only cost about $40 a pair after haggling with the vendor on ebay.

You also need a led light ring for the scope. For prepping you are best if the light source is very bright, white and close to the fossil. The goosneck fiber optic light sources are the best but they are very expensive. Hence go with the light ring. I bought a cheap one from china with 144 LEDs and the ability to increase or decrease the intensity (I always use on the brightest so that is pretty much a useless feature for me . It cost about $60 again after haggling with the vendor on ebay

Edited August 15, 2012 by Malcolmt

[bayoubengal]

Thanks, Malcolmt. Once again your advice was just what I was looking for!

[dirtdauber]

I've been using a PaleoAro airscribe for several years, averaging about 10-15 hours use per week, and have been very satisfied with its performance. Would advise purchasing both chisel-point and nail-point bits. Most of my work involves removing limestone and chalk matrix of varying hardness on fossils ranging in size from plesiosaur paddles to very small crabs and trilobytes. I use the scribe for 95% of my work, using my air abrader only for clean-up. I also use a dremel for smoothing background matrix and other hand tools as needed.

I run only one tool at a time at 90 lbs. pressure and use a 33 gallon capacity air compressor, which is sufficient, but a 60 gallon compressor would be better. Started with a 7.5 gallon compressor, but it ran constantly. I use a magnifying visor for all of my work (typically 1.8x power with 8-12" focal length) and this works fine for me, although a microscope would be ideal for the fine work.

George

[bayoubengal]

OK y'all, I've been doing some homework and I've got a new set of questions. First, the proposed setup thus far:

Kobalt 3.7-HP 60-Gallon 155 PSI Electric Air Compressor

air regulator/dessication unit of some sort

airscribe: Paleo Aro PAT-2S

Paasche 2000si air pen

Donegan DA-5 optivisor 2.5x mag

lights of some sort

DIY blasting cabinet/dust control

Now, some comments and questions. Malcomt, the scopes/lenses/booms you suggested are absolutely on my long-term shopping list but unfortunately I can't purchase all of the tools AND decent optics at one time. Eventually I'll be moving towards the setup you recommended. Ditto for the air abrasion; while I'm sure that I can get a much better setup than a Paasche with baking soda, that's going to have to cut it for now.

Can anyone recommend a decent air regulator/dessication setup? I'm new to compressors but this is one area I'd rather not skimp on.

Do I have the correct Paasche airpen picked out? Malcomt, I noticed your pics of the Paasche units with what appears to be large-bore hypodermic needles stuck on the ends. Paasche also sells some needles but I don't know whether they'd work for fossil prep. Any thoughts?

I'm still looking into lights but since I'm not buying a light ring for a scope just yet I was thinking about some sort of LED array above my workbench (my line of thought was that a bunch of cheap, bright lights from many different angles would be good for a workbench area anyway). If anyone has thoughts on economical but effective light sources that would be great.

Finally, I've decided to build my own blasting cabinet and dust control. I found a couple of links online but if anyone has any designs that have worked well for fossil prep I'd appreciate it.

Thanks again for your help!

[Malcolmt]

Actually they are blunt dispensing units not sharp hypos. The main reason I use them is that the overspray on the paasche unit is pretty wide and gets worse as the nozzle gets worn by the abrasive. These are dirt cheap and make it easy to be a bit more precise. The most usefull is the 1/2 inch long 18 gage. You can use the 22 Gage but then you need to have blast media that is in the 40 micron range.

You'd be surprised on the price of scopes on ebay sometimes if the auction is not picked up by many people. You can often get a decent zoom scope for about $100 if the bidding does not take off. I find the booms often sell for more than the scopes. Hence I made my own booms.

Just go with a pair of student goosneck desk lights that clamp onto the bench. Then put the large 150 watt equivalent white flouresent bulbs in them. Shine from different angles and you can eliminate the shadows.They do not get very hot , the problem with halogen lights is they just get too hot for my liking.

I use small inline mechanicall water separation on every line and a big wall mount desication unit that you fill with white desicant pucks on the central line leading in from the garage. I run my big compressor in the garage and run a line down into the basement prep area. I got my big desicant unit (its bright yellow and looks like a big iron pipe and is very heavy) at Princess Auto up here in canada which is like your Harbour Freight in the US. It was about $80 on sale. The pucks last about 6 months and cost about $30 to replace.

Edited August 27, 2012 by Malcolmt