nater Posted June 13, 2015 Share Posted June 13, 2015 (edited) Here is. 1.75" C6 Comet with 10% FeTi. It was just placed in a bottom fused mortar directly on the lift. As you can see, it shattered immediately. I'll use a piston next time. http://www.youtube.com/watch?v=0EvKV61GeR0 Edited June 13, 2015 by nater Link to comment Share on other sites More sharing options...
Rocketier Posted June 13, 2015 Share Posted June 13, 2015 (edited) Nater when making comets like that I pack them in gumed papertape and a disc on top. Leaving only the coreside open.They give a nice big tail without being shatterd. I use the tool shown in attachment.But I think the effect of a shatterd comet is nice. Edited June 13, 2015 by Rocketier Link to comment Share on other sites More sharing options...
nater Posted June 13, 2015 Author Share Posted June 13, 2015 It was a nice mine. I was hoping it would work just sitting on top of the lift for a "quick" and easy comet, but oh well. This was just a plain pumped comet. No core, dimple, shot hole or anything. In fact, I didn't even prime it since C-6 takes fire so easy. I suppose when something takes so long to dry, I have no excuse for not finishing it with a disc, a band of pasted paper or something to help keep it together. Maybe I will try curing one with phenolic resin whenever I get around to building a drying box. Link to comment Share on other sites More sharing options...
marks265 Posted June 13, 2015 Share Posted June 13, 2015 What about pressing them a little harder? I make comets up to 6" and lift and leader them as you hope to do and haven't had a problem. Just lift charge and QM under the comet wrapped in paper works for me. Looks pretty good otherwise. I bind C6 with 4-5 % dextrin. 1 Link to comment Share on other sites More sharing options...
Mumbles Posted June 13, 2015 Share Posted June 13, 2015 I've made mostly hand rammed comets of this general caliber. I converted to wetting them with gum arabic solution in addition to the dextrin in the composition. Without it, I was getting between probably 10 and 80% shattering depending on the composition. Not surprisingly, the ones with more coarse materials, especially charcoal, seemed more likely to fragment. When I switched to GA as the wetting solution, the fragmentation rate went way down, though the sample size wasn't as large. This is for hand ramming specifically. I'm sure it'd help pressed comets, but you can achieve much higher pressures and longer dwell times with a press that also would help as Mark mentioned. Link to comment Share on other sites More sharing options...
nater Posted June 13, 2015 Author Share Posted June 13, 2015 I could press it harder. I think it was pressed to 1500 psi on the comp. Like I do with stars, I used 4% dextrin mixed with the comp, dampened with warm water and allowed to rest overnight in a sealed tub. I am happy with the effect, so I could easily change how it is pressed and bound. Link to comment Share on other sites More sharing options...
ddewees Posted June 13, 2015 Share Posted June 13, 2015 I agree with Mark. Press them harder, and don't bother with the piston or wrap. Link to comment Share on other sites More sharing options...
marks265 Posted June 14, 2015 Share Posted June 14, 2015 At this point I remind myself of force drying some 4" comets once a little too soon. I usually like to let them dry on their own for about 3 weeks then I would put them in my dryer for a final attempt of removing additional moisture content. Usually this works pretty good. But on one occasion a couple of them cracked on top and just across the middle and not out to the edges. I thought for sure that I would see 2-3 pcs come out of the gun but they held together. Ever since, I've attributed it to consolidation as well as the binder to make them survive the lift charge, even with large cracks present. Not my cup of tea to shoot cracked comets but it was no less a learning curve. Link to comment Share on other sites More sharing options...
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