question

Not being able to spend thousands on a professional air-abrasive unit, I found an 'air eraser' for $10.00 at a discount hardware store today and snapped it up. Next I need to get acessories, and I need a few tips. First, the air compressor. They had a 10-pound portable unit for $72. While looking on the net, I saw a similar one for around $130. Anyone know a site where I could buy an acceptable compresser for less than $72? Next, what types of abrasives do a good job of removing matrix while leaving behind the fossil? Matrix will usually be a soft shale. And will a mask, safety glasses, and thick gloves be enough protection using a hobby-style abrasive unit, or do I need to get one of those cabinets?

Don Hilliker Intricate Articles

What you can get away with and what you should want depart from one another. On the compressor, I wouldn't settle for less than a 2 hp, 10-20 gallon tank unit capable of producing 90 psi at 4-5 cfm. Harbor Freight has one that approximates these specs and goes for around $140 on sale. An air scribe can also be driven by this machine. The unit is portable, with a horizontal tank. It does use oil and I recommend you invest in non-foaming air compressor oil and make your first oil change after 50 hours. Though it depends on how much you use the unit, I find myself changing oil in my compressors thereafter on about a 6 month basis. Larger tanks are nice to store compressed air so the motor is not always recycling. Make sure to drain the tank after use, taking the pressure down to about 7 psi at the pop-off valve release and then opening the tank drain. Leave the drain open until you next start the unit. Don't take care of your tank and it will rust out nicely.

Harbor Freight also sells a cabinet you can probably safely adapt to your end. You would at a minimum need to hook up your shop vacuum and you would be very wise to install gloves affixed to the cabinet where the slit arm-hole gaskets are. The cabinet is around $75 on sale. Wear a mask with 2 filter elements to prove your wise when using your machine and when dumping the vacuum.

200 mesh dolomite can be bought in 50 pound bags from a ceramic supply for less than $15. It is a good abrasive and its hygroscopic affinites shouldn't be a problem if you remember to empty the powder chamber and blow out the orifice on your eraser when you plan to let it sit for any time. Keep your powder dry in storage and use. You will need to put filters on your air line to remove moisture. Call a professional automotive paint store for pointers.

Some magnification when working is very valuable. Optivisors work well and won't make you rob a bank.

Regards,

Edward Hennessey

unit, I found an 'air eraser' for need to get acessories, and I portable unit for $72. While know a site where I could buy an abrasives do a good job of removing soft shale. And will a mask, hobby-style abrasive unit, or do I

Not sure how this ended up in a paleoanything group!

Use www.google.com to find

Badger Pond Power Tool Forum

and you might find it interesting.

Jois

Because the setup is to be used for prepping fossils? I can't think of a group that would be MORE appropriate for the question! Or more likely to generate useful answers (as have already been done, thanks for the tips, I can drop a couple or three hundred on this, but not the thousands necessary for commercial/research grade prepping).