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I know I will regret posting this, especially after reading about @Fossil-Hound‘s 60-gallon behemoth, but has anyone tried Harbor Freight’s new ultra-quiet Fortress air compressor? I would only be using it for air abrasive work (probably with a Paasche AECR or similar), not air scribes, so I don’t need gigantic capacity. (Sidebar: I know I would not have the ability to ever use it with scribes in the future, no need to lecture me about that.) Green River fish and Wheeler Range trilobites are the kinds of things I would use it for. I have already built my blast cabinet. I don’t have a lot of room and I really like the idea of it being quiet. The reviews I have read so far make it sound much better than other brands but I’d like feedback from someone who has really used it if possible. Here’s a link to the one I’m looking at: https://www.harborfreight.com/2-gallon-12-hp-135-psi-ultra-quiet-oil-free-professional-air-compressor-64596.html

I figured this might be a good thread in case it comes up for anyone else in the future. I recently purchased a used S. S. White 6500 model micro sandblaster unit for my workshop, which from here on out, I will likely refer to as a lab, as it now contains a higher dollar value of equipment than my media production office. Upon arrival, I discovered that it was not only pretty well used, but very poorly maintained, and was in fact, not functional. Since I got it for an absolute steal on the auction site, it's still worth every penny. After disassembling the unit, which I didn't have the foresight to photograph, I was fortunate enough to get on the phone with Joel, the president of Airbrasives, the subsidiary of S. S. White that manufactures these units. Joel was extremely nice, very talkative, and exceptionally helpful. We spent more than 90 minutes on the phone discussing the specific model, the parts that tend to wear out first, and what to look out for in terms of repairs and potential future pitfalls of maintenance. I figured that since I have had this experience and will be rebuilding this seized unit over the next few months, it might be a good project to share in case anyone else is able to get a similar bargain.

Hi all, I have been searching through posts in the forum about various types of abrasives, and I can't seem to find a comment anywhere where someone breaks down the pros/cons of the different forms of abrasive and their microns. Of course I realize everyone has their own preferences, I am just confused as to the objective benefits of what looks like the three main types of abrasives: dolomite, aluminum oxide, and just plain baking soda (besides the fact that baking soda is more delicate.) The Paasche Air Eraser comes with 240 micron aluminum oxide, but that seems to be a little extreme for fossil preparation, is there an appropriate time and place in which I could use that? What would be the max (or even a general range) micron of either dolomite or aluminum oxide that one would recommend I use for 1. Green River fish, 2. trilobites, 3. ammonites, or 4. just general fossil clean-up?

Wanting to move beyond dental picks. Right now I have a dremel I’m think about using for fossil prep but am worried about maintaining control as it tends to pull. The other options I am seeing are air scribes and abrasive blasting. Which is best? Which is the next logical step?

I just got back from a week-long trip that included a stop to dig Green River fish at the American Fossil Quarry outside of Kemmerer, Wyoming. That was a successful venture and I will post a separate entry showing some of my finds once I get them unpacked. While I was there, I stopped in at the nearby Fossil Butte National Monument. In the visitor center, one of the rangers was doing a demo of prepping a Green River fish (a Diplomystus from the 18" layer they got from one of the commercial quarries). I didn't take any photos but I did ask a lot of questions. Before I share his answers, you might want to take a look at this video from the Fossil Butte National Monument website. It shows how they prep the fish using an air scribe and air abrasive. But be warned that what I learned isn't exactly the same as what is shown in the video here: https://www.nps.gov/media/video/view.htm?id=9BD712EE-1DD8-B71B-0B88EC525E86D328 The setup I saw was the same as in the video. It looked like a home-made blast cabinet with a sheet of acrylic plastic on top, held on by blue painters tape. It was connected to a good dust collector. The microscope, as in the video, looked like a Leica-Wild M8 stereomicroscope with a video camera on top and an offset binocular viewing head. This is a top-of-the-line unit that probably cost somewhere between $7,000 to $10,000 (sadly, this model microscope is no longer manufactured, but you can pick them up on the used market if you have enough money). The microscope seemed to be fixed in the center of the blast cabinet, you move the specimen around under it. I didn't learn the make of the air scribe tool he was using, he said it was a specially modified one with a large rubber sheath that reduced the vibration transmitted to his hands. For the air abrasive, they had two Crystal Mark Swam Blasters model EV-2. One of them, set off to the side and not being used, was labeled "Dolomite." I asked him what abrasive he was using and he said iron powder. I was surprised because I thought that would be much too hard on these fossils, but as I watched on the screen it did a great job of removing the matrix without damaging the fossil. I probed some more and he said that while the machine could be set to go up to 80 psi, he had it set to 13.3 psi. There is also a setting for powder flow that can be set between 1 and 10. He had it set to 6, and when he is doing delicate work on the fins, turns it down to 2 or 3. He also said the nozzle was specially modified to be smaller in diameter. I was pretty impressed with the quality of his work and am inspired to make my own blast cabinet similar to theirs (but without the high-priced microscope). I thought everyone might like to know what works for this facility even though it's different from what is usually recommended here on this forum.

I recently got a new air abrasive as my old one finally bit the dust. The old unit was a paasche air eraser that was pretty decent, but the up time I got from it was pretty low as I spent a good amount of my time refilling the really small canister with abrasive. I decided to get a remote Paasche AEC unit to remedy the problem I had with the old unit, but as of now I'm firmly disappointed with it. My problem is I am getting almost no abrasive cycling through the unit. I'm not getting clogs at all, and the air is moving freely from the compressor to the end of the unit, with pretty good air pressure being output. I dried my abrasive in the oven for about an hour at 250oF to dehumidify it after I noticed the lack of powder flow, thinking moisture was the issue, but that doesn't seem to be the case. Anybody have any ideas? Right now it is taking me probably about a minute to remove a thin film of shale off of a single crenulation of a small (.25 inch) brachiopod. Occasionally my unit will spurt out a bunch of abrasive at random, and when this occurs the cutting rate is pretty good, not as good as my old unit, but certainly serviceable. Shaking the canister can artificially boost the powder flow, but only during the duration of which it is being shaken, and clearly this isn't a good way of achieving the effect I want. For those who may be curious, this is what the unit looks like:

Just got an email from Harbor Freight about a new compressor they have introduced. It’s only 8 gallons so it might be too small for a scribe, but I think would be okay for an air eraser like the Paasche AECR (as long as you keep it set to 50psi or less). It is oil free but claims to be quieter than other oil free compressors. At $115 on sale it might even be in my price range. Anyone already have one or have thoughts about it? Here is the link: https://www.harborfreight.com/8-gallon-15-HP-150-PSI-Oil-Free-Portable-Air-Compressor-64294.html?ccdenc=eyJjb2RlIjoiMTIxNTkwNjAiLCJza3UiOiI2NDI5NCIsImlzIjoiMTE0Ljk5IiwicHJvZHVjdF9p ZCI6IjEyNjExIn0%3D &utm_medium=email&utm_campaign=1718c&utm_source=1031&cid=mEmail_s1031_c1718c&sfid=c3RldmVfaGluY2hAY29tY2FzdC5uZXQ=

I'm ready to take the next step in preparation and start using a microscope. What is your method for using it for prepping? Do you use it outside the sandblasting cabinet, and set it up so it looks through the cabinet's glass? Or no cabinet? If that is the case, how do you protect the microscope optics from the abrasive? Also, any recommendations for a starter microscope? $300 or less... Thanks!

I picked up this Airbrasive model H from a machine shop the other day for a decent price. The shop still had it in production and it seems to have been taken care of pretty well. Can anyone tell me how old it might be? Also looking for a manual if any of you S.S. White users know where I can locate one. Looks like the vibrator has been replaced and everything seems to work on it. I'm thinking the hand piece should be replaced with something else but not quite sure where I want to get that. I typically use dolomite (44u crystal mark) on the shale I collect from the Maquoketa formation of N.E. Iowa. Any advice or tips on this unit would be greatly appreciated! Thanks.

Anybody ever try this mini sandblaster from Micromark for fossil preparation? I would be amazed if it worked but thought I would ask: http://www.micromark.com/microlux-grit-blaster,13027.html

Hello everyone! So i have been hard at work. Last time I damaged a couple of fossils because the PSI on the sandblasting machine was too high while I was working on removing matrix directly off the fossil. This time I learned that higher pressures like 20 or 40 PSI can be useful for removing large amounts of matrix that are not directly touching the fossil. While lower pressures like 5 PSI are useful for removing small amounts of matrix to expose details of fossils. Also it is a good idea to wait to expose details until the entire fossil is mostly exposed and only detail work remains. This is because the more a fossil is exposed and being worked on the higher chances are that details will be erased by the air abrasive moving over the fossil. Even in areas you are not directly working on. Please watch my video and learn more about it! Special thanks to the University of Utah for letting me use their lab, and a special thanks to the University of Utah Undergraduate Research Opportunity Program for helping too!

Hey guys! So I thought that I would start a new blog here. I have been looking for videos and other instructional material on line for how to prep / clean a fossil and have not found much. Google did not seem to be to helpful in this matter. I did find a few more things on this forum and they were very helpful. I learned what materials I needed and some techniques of how to clean fossils, but nothing like "Make sure to do this.....", "don't do this....". So I was able to gain access to my School's Palio and geoscience lab, and we put together a fossil prep lab. Now it may not be as fancy as a museum but it works!! And I am excited to work there! I may also be able to go to a nearby museum and be trained in how to do this as well. We will see. So I have some trilobites from the wheeler shale formation, in Dugway Utah, that I will be practicing on. The point of this is to get my skills high enough to be able to work on other fossils with out damaging them, for a research project I am involved in. In the video I show you what I do and talk about why and also talk about what I do wrong and how I fixed them. Please feel free to talk about this and to give advice. Here is a video of what I have been able to do so far. I started a youtube channel so that everyone can see what I am doing. So far I found that if i put a circled groove around the fossil, hopefully deep enough, that when I break the parallel layers of shale below the fossil that it will let the fossil be removed, with some matrix, from the rock. I will then later remove the excess rock off the fossil with an air abrasive / sandblasting machine. After I put the circled groove around my trilobite fossil I put my finger on it so that way it does not fly away when I use the air pen to pop it out. I had some success with this. I also found that keeping the PSI on the sand blasting machine around 5 PSI was necessary. Anything higher then that and I was damaging the fossils I found this out the hard way. I damaged two fossil because I did not check the PSI on the machine before I started. Fortunately they are ones that I own and not some one else. Best check that PSI next time!! Well enjoy my video! and remember please share this with others who are interested in getting started. And feel free to give any advice I would need for a beginner! Zach

Thank you all for being incredibly helpful. I have a Paasche Air Eraser on the way and I have seen pictures of people using Hyperdermic needles as nozzles but I haven't seen how they do it or where they get the needles. Can someone point me to a tutorial? I have checked Google and searched this forum, the best I have found is the end result of what it looks like. Thanks, Adam

Anybody used a Prep start Air abrasion unit for cleaning fossils, was looking to purchase one for my home workshop and was wondering if any of these dental units are useful for prepping fossils? Mainly the Prep start though as this is one i have an option to buy. If any one has a video of one in action that would be brilliant, or images of work they have done with one, that would be most useful. Cheers Dan