Phil Posted October 23, 2021 Share Posted October 23, 2021 I've pretty much calmed down all my pyro operations since the 4th but I got a bonfire going last night and I figured out of boredom I'd do a quick batch of cedar chips while I'm at it. Is steel slingshot ammo okay for a cheap quick way to process these chips into powder? https://www.walmart.com/ip/Daisy-8183-Powerline-3-8-Inch-Steel-Slingshot-Ammo/37201711?fulfillmentIntent=In-store If it's not absolutely airfloat with this that's okay, I just need it down fine enough to where I can reasonably store it without crushing it in a bag or something. Link to comment Share on other sites More sharing options...
Arthur Posted October 23, 2021 Share Posted October 23, 2021 Steel balls will be fine for charcoal, but useless for oxidisers or mixtures. -Oxidisers will cause the balls to rust and rust (Fe2O3) is a rate increasing catalyst for BP comps popularly used for adjusting rocket motors.Professionally ingredients are bought an stored in mesh cuts likely to be wanted so milling some charcoal and having say 4, 20, and 100 mesh cuts already made is a great plan Link to comment Share on other sites More sharing options...
justvisiting Posted October 23, 2021 Share Posted October 23, 2021 Arthur, I've read about using iron oxide in sugar motors before, but never in black powder motors. Do you have any more info on that you could share? Specifically, I wonder if using iron oxide could speed up slow (75-15-10) nozzleless rocket propellant- or even lift made with a less than ideal charcoal? Thanks for any advice on it. Link to comment Share on other sites More sharing options...
Arthur Posted October 24, 2021 Share Posted October 24, 2021 Red iron oxide certainly increases the rate of burn of BP if added in the 0.5 to 1.5% range. However this was from a conversation with Rev Lancaster and I don't have precise details. Firstly it's best to make the fastest powder you can by using the best material for rate (Balsa charcoal is said to be the fastest) Then milling the powder til no more performance increase is found with increasing milling. Link to comment Share on other sites More sharing options...
robbo Posted October 24, 2021 Share Posted October 24, 2021 I'd be interested to see some test stand to data validate this, if true. Link to comment Share on other sites More sharing options...
Arthur Posted October 25, 2021 Share Posted October 25, 2021 Sorry but if you want then do some tests yourself. Make some powder add 0.5/1.0/1.5% to portions of it and make the motors perfectly, then publish your results here. I don't make rockets ever, but I did spend some time talking to Rev Ron Lancaster while he still had a factory. Have you read his book? It's full of interesting formulae? Link to comment Share on other sites More sharing options...
robbo Posted October 25, 2021 Share Posted October 25, 2021 I'm just sceptical since it seems like such a simple (although not obvious - at least to me) additive that isn't widely used. I'm not a rocket maker either so I have no way to definitively test the assertion. A rocket test stand would be ideal. I just find it curious that this hasn't already been widely disseminated within the BP rocketry crowd since they are so often interested in optimization. Maybe it is a phenomenon peculiar to unmilled, nozzled rocket propellant? I have no idea. I've never head of it's application in the making of milled BP lift/burst either. That having been said, in the 40+ years that I've been involved in pyrotechnics I've heard many endlessly repeated "facts" by "experts" that have not quite turned out to be true (e.g., precise timing can't be achieved with time fuse, one can't use round stars in large multibreak shells, one can't allow chlorate to contact S, etc.). So I hope that perhaps someone can definitively find out if iron oxide is a cheap burn rate enhancer for BP and, if so, under what conditions. I'm sure I could find a use for faster powder... Link to comment Share on other sites More sharing options...
Arthur Posted October 25, 2021 Share Posted October 25, 2021 Most people I'm aware of do not need to speed up the burn of good BP to make a rocket with nozzle, in fact many people slow the burn by adding extra charcoal to ensure that the casing survives to apogee. One of the tables in Lancaster's book is BP formulations for BP rockets. For small rockets he suggests straight BP but for increasing sizes he suggests the use of extra charcoal about 5% extra charcoal for each increasing bore size IIRC. Link to comment Share on other sites More sharing options...
Guest Posted November 13, 2021 Share Posted November 13, 2021 (edited) https://pgnbearings.com/collections/3-8-slingshot-ammo The Daisy slingshot ammo is zinc plated, in case that matters. The PGN ammo is coated in light oil, so it has to be cleaned first. I like to use combinations of sizes when I mill, determined by what I'm milling and what size it starts out as. When I start with smaller particle size material (not metal and less than 20 mesh), I use a combination of 1 part 3/8", 2 parts 5/16", and 3 parts 1/4", and it mills down to airfloat pretty fast. My aluminum milling media ratio was; Stage 1 - 3 parts 1/2", 2 parts 3/8", and 1 part 5/16". Once it's down to about 40-60 mesh, I switch to Stage 2 - which is 1 part 3/8", 3 parts 5/16", and 9 parts 1/4". Edited November 13, 2021 by Guest Link to comment Share on other sites More sharing options...
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