In addition to what has already been mentioned on this topic, I would like to see added safe guards when screening on a large manufacturing scale.
If possible,..... personally I would like to see some form of R&D along the lines of curtaining around the trays to help reduce atmospheric dispersal of comps into the surrounding air, along with a curtained/funnel hopper device to dispense comps into trays, as well as a remote control sifting trays ( a bit like a concrete vibrating table when you make paving slabs done via camshaft set up), all this could be done in a remote setting to help reduce human contact/fatalities.
A company in the US actually investigated the automated sifting machines. They had a guy at their plant who was the sole mixer of flash, and it was done in some somewhat isolated building. He happily did his job for quite a while I had heard. They invested in a machine to do it for him. I don't think it was entirely remote though. I believe the operator still had to be near by, to put the powder back on top of the screen, or to rub through any clumps or anything like that. He imediately quit, saying he wasn't comfortable. Within 2 weeks, the machine had blown up, and he was back in his brand new building happily hand screening flash. I don't think the new operator was injured. If you've ever seen a motorized sifter, such as for grading metal powders, you'll see how violent they really are.
Honestly, up until last summer it scared me to death, the thought of screening flash. I went to a friend's house to build some bigger shells, with bottom shots. I figured he just diapered it, like I assumed everyone did. 800g a bottom shot really eats up flash powder, in addition to the lampares were were making. We calculated it out, and figured we needed around 18.5lbs of flash. He had me start weighing out dark Al, and perc in 2.5lb batch increments, and broke out a screen. I ASSumed that he was just going to screen the perc onto the paper and diaper, because it was a bit clumpy. He showed me how to do it, and handed me the screen. The first batch was one of the scariest experiences of my life.
I now practice kind of a hybrid method. I screen the materials through a screen onto a paper, and diaper a bit to get them good and mixed. I then SIFT the flash together onto a new sheet of paper. You will be very surprised to see how much unmixed perc and blackhead Al remains. I diaper again, and give it a final sift, and it is pretty much homogeneous. He had be screen it 4 times with no diapering. You just have to be careful. Normally I make it first thing in the morning outdoors or in the afternoon after it rains (high humidity), and make as much as I'll need for one day of building. All cotton clothing, and copious amount of anti-static spray on everything. I don't bother with gloves or glasses, but I do use a half face respirator. With the amount of flash I mix, a face shield isn't going to do anything.
Honestly, one of the biggest dangers of mixing flash is spilling it on the ground or table, and stepping on it or grinding it accidentally. I always work in the grass on a wooden table, and clean up between every batch. A paint brush is used to brush off the table. There is an unsettling amount of flash there on occasion.
