jacob Posted December 9, 2008 Posted December 9, 2008 Thanks tentacles, I had heard that too much heat will and won't hurt Stainless, that makes sense though.
mike_au Posted December 10, 2008 Posted December 10, 2008 I'm not sure you want to use brass to mill KClO3, there could be an incompatibility there, corrosion related perhaps, and besides that it's sort of a waste of good brass media.. What is the preferred media for KClO3? Alumina? What do you mean a waste? What should I be saving the brass for?
tentacles Posted December 10, 2008 Posted December 10, 2008 Yeah, most people use ceramic for milling oxidizers.. And they would use the brass to mill BP, brass makes quite good bp, as it's very dense and hard enough not to wear.
rev.redneck Posted December 10, 2008 Posted December 10, 2008 (edited) I use lead it works, I had a idea the other day, I used a cigarette lighter from a car on a 7 amp 12 (13.68 really) volt supply, it gets really hot. the idea is to test comps, i uploaded a vid to utube but it has not showed up yet (a day later?). My question is how or if I could use it to test ignition temp's of comps? ahh fixed vid:http://www.youtube.com/watch?v=wCUNfdTJTkg also burning random whatever scraped off my table. Edited December 10, 2008 by rev.redneck
mike_au Posted December 10, 2008 Posted December 10, 2008 Yeah, most people use ceramic for milling oxidizers.. And they would use the brass to mill BP, brass makes quite good bp, as it's very dense and hard enough not to wear. Righto, I am happy enough with lead for BP I just wanted something that wouldn't turn my KNO3 grey. I will keep the brass for KNO3 for now, when I get enough to fill my big jar I will use it for my BP (hopefully by then it will have rounded the edges a bit) and I will add ceramic media to my list of things I have to sort out before I think of making chlorates.
Mumbles Posted December 10, 2008 Posted December 10, 2008 I'd be weary to use brass, or anything containing copper really, on chlorates. There is some big scare of forming copper chlorate, which is explosive. I'd mostly avoid it because copper, and most other transition metals, sensitize chlorate and perchlorates.
firetech Posted April 28, 2009 Posted April 28, 2009 I found these tapered pins while searching through the hardware store one day...thought they'd make good rocket tooling if i stick em in something. Anyone have 4oz core-burner rocket tooling that could share the specs of the spindle?
FREAKYDUTCHMEN Posted May 19, 2009 Posted May 19, 2009 2 starrollers I've build this spring:http://www.pyrobin.com/files/p1040018.jpg http://www.pyrobin.com/files/p1040019.jpg Finished:http://www.pyrobin.com/files/img_0068.jpg
swervedriver Posted May 19, 2009 Posted May 19, 2009 Beautiful star rollers Dutchmen. I'm interested in what you use as a mold for the barrels? Looks like maybe big balloons or beach balls for molds, but I can't see how a balloon would be strong enough to glass over. Very nice work, those should last a while...
FREAKYDUTCHMEN Posted May 19, 2009 Posted May 19, 2009 tadaaa:http://www.r-fun.nl/website/images/kinderfeestjes/skippybal1G.jpg
Swede Posted May 19, 2009 Posted May 19, 2009 (edited) WOW! Very nice job, professional in every way, and not just one, but a pair. FDM, are you a pro, or just a dedicated amateur pyrotechnician? Those star rollers look good enough to outfit a small company. Good inspiration on what can be made by a motivated guy. Added: I just noted, you mounted a VFD (Variable Frequency Drive) on those puppies, giving you 100% control of the speed. Amazing! Edited May 19, 2009 by Swede
lostfido Posted November 17, 2009 Posted November 17, 2009 OK, I'm bumping this old thread. I have a question on star plates. Is the thickness of the female part proportional to the diameter of the pins? An example: 3/8 pins and 3/8 thick female plate, 1/2 pins and 1/2 thick plate, 3/4 pins and 3/4 thick plate etc....I may just buy a couple of plates and not worry about it, but a friend has a digitally controlled "Bridgeport" and a similarly controlled metal lathe in his garage that I have access to as long as I pay in beer!!!! It's getting to be winter in the tropical state of Minnesota and I need some morning projects on the weekends before I start my version of the Buffalo Theory by Cliff Clavin. "Well ya see, Norm, it's like this... A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it is the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members. "In much the same way, the human brain can only operate as fast as the slowest brain cells. Excessive intake of alcohol, as we know, kills brain cells. But naturally it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine. That's why you always feel smarter after a few beers."
TheSidewinder Posted November 18, 2009 Posted November 18, 2009 Ah yes, pearls of wisdom from Cliff Claven. But don't start complaining about Winter just yet. Not with the temps we've had the last 2 weeks. I hope the Farmer's Almanac is wrong about this Winter.
Arthur Posted November 18, 2009 Posted November 18, 2009 In single pressing of pharmceutical tablets it's normal to allow a 2;1 compression from free flowing powder to pressed tablet but that is for filling the hole then pressing once to a pill. filling and repeatedly compressing the powder will give a star closer to the volume of the cavity.
Mumbles Posted November 18, 2009 Posted November 18, 2009 Most star plates I've seen are slightly thicker than the diameter of the star. IE 1" thick on a 3/4" plate or 1/2" thick on a 3/8" plate. I don't recall any specific ratios off hand. The comp can either be smeared in like peanut butter, or granulated and filled and compressed. The filling with granular comp is repeated 2 or 3 times. If you want to get by with 1 press to a finished comet, off hand I think that is around 3x the height.
lostfido Posted January 4, 2010 Posted January 4, 2010 Most star plates I've seen are slightly thicker than the diameter of the star. IE 1" thick on a 3/4" plate or 1/2" thick on a 3/8" plate. I don't recall any specific ratios off hand. The comp can either be smeared in like peanut butter, or granulated and filled and compressed. The filling with granular comp is repeated 2 or 3 times. If you want to get by with 1 press to a finished comet, off hand I think that is around 3x the height. Here is my first star plate. I made this 3/8 plate on two pieces of 6061 T6 aluminum and made the pins out of the same type of aluminum bar stock. Here is what I have learned. 6061 round stock is not held to very close tolerances at .006, 2011 and 2024 are much closer at .00015. So spend the extra money on the good stuff, your hands will thanks you from not having to sand the extra couple thou off. I don't know if this is what I should have use for the thickness of the plates as both top and bottom are 1/2 inch. I see some of the tool guys use 1 inch for the pin plate and 3/4 for the female plate. I am not sure why?????? Oh well, I'm not going to quit my day job and become a machinist, but I have made my first usable tool and the cost was very reasonable. Fido
swervedriver Posted January 4, 2010 Posted January 4, 2010 wow, that's nice. Maybe the thicker pin plate is for torsional strength against warping or bending while pressing, while the female plate rests on a flat surface so it doesn't need to be as thick? anyhow, great job
lokys Posted January 4, 2010 Posted January 4, 2010 (edited) This is my selfmade 6mm starplate x90 holes: http://i653.photobucket.com/albums/uu257/rimokas/201001043557.jpg http://i653.photobucket.com/albums/uu257/rimokas/201001043558.jpg plate - aliuminium Pins - brass Weight: 2,1 kg Work with this starplate is good. Edited January 4, 2010 by lokys
Swede Posted January 5, 2010 Posted January 5, 2010 Agreed... a starplate from metallic materials like those is neither trivial nor cheap. Nicely done.
lokys Posted January 6, 2010 Posted January 6, 2010 (edited) very nice!how do you made it?First, I took two aliuminium briks 50mm x 250mm x 20mm. I driller holes trough first and half way trought second (very important:holes would be drilled 90 deggres n), then inserted pins of brass using epoxy. And of course expanded plate's holes to 6.5mm by drilling themagain with a bigger drill bit. That's all. Edited January 6, 2010 by lokys
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