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I would like to start a new thread: How do you prep at home? I hope there will be some interesting tricks, methods and equipment shared. Everyone is invited and encouraged to post their equipment, their experiences, their solutions to problems, and their preparation tricks here. Let me start with my equipment. We had an oil heater in the basement and an oil tank about 3000L in size. After the tubing in the boiler room burst twice in 25 years and the room was flooded with smelly diesel oil, we decided in 2016 to install a groundwater heat pump and scrap the oil heating including tank. I immediately took the opportunity, occupied the room and set up my sandblasting equipment there. I use two sandblasting units: on the right is my main DIY unit that I built a few years ago – the design instruction can be found here: On the left is the small unit that I actually rarely use. I operate the small unit with iron powder that I have sieved over 45µm. This very fine iron powder trickles somewhat badly, therefore a magnetic vibrator is installed under the blasting agent tank. In the large unit I use almost only iron powder, which I sieved over 150µm. Here, too, I have installed a vibrator, but not a magnetic vibrator, but a turbine vibrator driven by compressed air. With the large unit, I can work for longer than two hours and then I need a break anyway. Using a foot switch, a solenoid valve and a pneumatic cylinder that squeezes off the hose to the blasting nozzle, I can interrupt the blasting flow almost instantly without a lot of abrasive running down. Iron powder is more expensive than bicarbonate, but since I can recover it, it is cheaper in the long run. I got myself 25kg of iron powder in 2016 - that will still last for years. For recovery, I use the two cyclones on the left. I blow the exhaust air into the open air. I have installed strong permanent magnets in front of the intake opening of the cyclones . Since the chamber IS very large and most of the iron powder sediments beforehand, almost nothing gets into the cyclones - only rock dust. To clean the chamber from time to time, I use an electromagnet to conveniently collect the iron powder. With the electromagnet, I can also easily separate the rock dust from the iron powder. Some rock dust is carried away by the iron, but most of it remains when I switch on the electromagnet. And when I repeat the procedure with the electromagnet several times, the iron powder is almost free of rock dust. Of course, since I can recover over 95% of the iron powder, I have to sift it frequently. This was too exhausting and boring for me. I have therefore built myself an automatic sieving unit. The sieves stand on a plywood board, which is mounted on four springs and can swing freely. The board is set in motion by a turbine vibrator driven by compressed air. Within a few minutes the material is sieved. So that I do not have to watch the whole time, I have built a mono-stable trigger circuit, which automatically switches off the solenoid valve after 10 min (the grey box in the picture below). Within a few minutes, the material is sieved. So I do not have to pay attention all the time, I have built a simple circuit (mono-stable trigger circuit) for myself, which automatically switches off the solenoid valve for the turbine vibrator after about 10 min. The sieves are from China, not exactly the best quality, but quite sufficient for my purposes and available at a tolerable cost. When sandblasting, I always work under a microscope. I bought my Olympus microscope cheap from Malaysia via the internet (at that time the method of quality control was changed in the semiconductor factories and the microscopes were discontinued). To achieve a sufficient working distance, I use Barlow lenses. I have a whole set of them. With a 0.25x attachment lens I achieve a working distance of about 40 cm, but mostly Barlow lenses with a magnification factor of 0.3 or 0.4 and working distances of 18 to 35 cm are sufficient. For illumination I simply put two 50W LED lamps on the glass plate - then I don't need the ring light on the microscope. The X-ray unit on the right side I found on a scrap pile and repaired it. I have to develop the X-ray images myself, but I can still do that from times when there were no digital cameras (you can tell that I am almost a fossil myself...). The X-ray machine is operated from another room for safety reasons. For simple images, the device is still suitable - for better pictures I can go to Munich to the paleontology department there (but then I have to beg a little). The compressor was too loud for me, I installed it in another room and moved a rigid compressed air line into the former boiler room (now prep room). Nevertheless, I regularly use hearing protectors (I can always say I didn't hear my wife calling me). I make a lot of effort to produce dry air - as you can see on the pictures, I have three water separators connected in series (separators with 5µm, 1µm and 0.1µm pore size). Since then, I have had no more problems with clumped abrasive and blocked nozzles. If, exceptionally, I want to use bicarbonate as a blasting medium, I have to clean the blasting chamber completely before and afterwards. Bicarbonate attacks the iron powder and it starts to rust. This wouldn't be too bad in itself, but it reduces the flowability of the powder noticeably. Sometimes I use the box when I work with my pneumatic pens, but for that I actually built a smaller, simple preparation box (without suction). As blasting nozzles, I usually use Renfert IT nozzles with nozzle openings between 0.6 and 1.2mm. As a rule of thumb, you can use "nozzle opening should be about 8 times the grain size". So, for the 150µm iron powder, I use a 1.2mm nozzle. When blasting, I rarely work with high pressure, usually 2 or 3 bar or less is sufficient for my substrates. In the meantime, I also make the nozzles myself from tungsten carbide tubes. Complete blasting pens with a nozzle opening of 1.2mm (and only 1.2mm) can also be bought cheaply via Aliexpress.

I have started prepping Green River fish for one of the quarries in Kemmerer and one of their requirements was that I switch to using iron powder for my abrasive. It's expensive but I wish I had done this years ago! It took a fair bit of cleaning to get the baking soda out of my dust collection system (you don't really want them mixing together). Iron powder is slightly harder than soda but is more rounded. It removes the matrix really quickly with less damage to the specimen. I can operate at significantly lower pressures as well. The softer bits of matrix come off easily at 8 psi. Another aspect of the iron powder is that it is easily recoverable with a magnet in a bag. about 50% drops in the box. I pick it up with the magnet, sift it through a 100 micron sieve and dump it back into the abrasive hopper. My dust collector dumps into a bucket to collect the heavy/large particles on the way to the fines bag. This grabs about 90% of the abrasive that gets picked up by the suction. I have another magnet in the bucket that gathers most of the iron and every 4 or 5 hours of work time, I open the bucket and recover the abrasive. This gets sifted and goes back into service.

I have recently read on Fossil Forum that there are excellent results when using fine mesh iron powder as an abrasive. I have used dolomite and sodium bicarbonate on trilobites with a Swam-blaster with not good results. Where can I obtain 325 mesh (40 microns) IRON POWDER for prepping trilobites? Thank you for your anticipated assistance, BFLADY