Mumbles Posted September 30, 2008 Posted September 30, 2008 You can move slowly to a smaller nozzle, say 2.5mm. It only takes one cato to know you've gone too small. Another common method is to mix in whistle mix. This must then be pressed though. The normal nozzle for an end burner is around 1/4 the ID, so you still have a little room to spare before you get there.
TheSidewinder Posted September 30, 2008 Posted September 30, 2008 *****SNIP*****My BP is about as hot as it is going to get *****SNIP***** How, exactly, are you making your BP (Mill, rock tumbler, hand-grinding, etc), and for what time period are you grinding the mix? Are you ramming or pressing the motors? If pressing, what force? If ramming, using what type and weight of hammer? Give the details and someone will almost certainly be able to give you good advice. Edit: Damn, squirreled by Mumbles.
nickle Posted September 30, 2008 Posted September 30, 2008 How, exactly, are you making your BP (Mill, rock tumbler, hand-grinding, etc), and for what time period are you grinding the mix? To answer your questions BP is ball milled for a minimum of 12 hrs. before use. I also ram the rockets about 1/8 teaspoon at a time with a 1.5 lb. dead blow hammer, four good wacks per 1/8 teaspoon. Whistle mix is not an option at this time, since I am a beginner and think I should master BP before moving on.
TheSidewinder Posted September 30, 2008 Posted September 30, 2008 On the face of it, that sounds correct. But, if your "Ball Mill" is actually a rock tumbler, double that milling time to a full 24 hours. The volumetric amount of media and chemicals is also important. That hammer may be a bit light, actually. And are you using a sleeve on the casing? Without one, you usually can't hit the rammer hard enough to adequately ram the grain without splitting the tube. (At least, that's been my experience.) Have you done a burn-test with your finished (and riced/granulated) BP? What were the results?
Mumbles Posted September 30, 2008 Posted September 30, 2008 There are two things I can suggest assuming that nothing material-wise is to blame. Firstly, give it a couple more good strikes. At least 8-10. It's possible it's not compressing enough. Secondly on a related note, ensure you have a good solid base for striking on. We were ramming rockets last weekend at a club seminar. There were about 5 stations, and 2 of them were consistently having poor performance and CATOS. Generally slow take offs, or early burn throughs. It was determined that it was the ramming base. Those two were using too light of wooden bases, and were jumping a bit upon ramming. This caused insufficient compaction. The same done with an end burner would probably produce similar results to what you're using. It's possible it's also your charcoal. You don't mention what you're using, but a fairly reactive one will be neccesary.
nickle Posted October 1, 2008 Posted October 1, 2008 (edited) I really appreciate all the help and suggestions. I do not have a video camera so the best I can do is a description of the BP burn test. When testing the meal powder I get an almost instantaneous "woosh" and the riced/granulated gives me a "poof" and its gone. Sorry about the description but it's the best I can do under the circumstances. The suface that I ram on is a concret slab, although as sugested I may not be pounding it hard enough with the hammer. I usually mill 170 grams (6oz) of BP at a time using 1134 grams (2.5lbs) of lead media in a 3lb. mill. The charcoal is something I have thought about, I am using the Cowboy brand "lump" milled to air float. I had a hard time finding that here in the northeast got the last 2 bags from Lowes. I do not have enough BP left to construct any more rockets at the moment so I will have to make another batch, don't want to mix the old with the new adding yet another variable. When the new batch is done and few new rockets are made up using the advice received I will report back, hopefully a happy camper. Edited October 1, 2008 by nickle
Mumbles Posted October 1, 2008 Posted October 1, 2008 It might be the charcoal. I've had mixed results with the cowboy charcoal. I got better results by picking out the softer pieces(maple primarily I think), and leaving the really hard pieces(oak I think). It works OK for lift and sparks, but not the best in either regard, though a happy medium. I like it for things like charcoal streamers and spider stars. Might want to consider making a more reactive charcoal to see if that solves anything. A small batch of willow, or a variety of others will easily give the answer. Given your batch size, you'll only need an ounce or so, which could be made in a soup can or so.
FrankRizzo Posted October 1, 2008 Posted October 1, 2008 Tentacles posted a link to a lump charcoal review site that he found. It listed the burning characteristics (burn time, ash production, etc.) of most of the major lump charcoals available. Bark and clay fillers would tend to leave more ash, so brands with low ash likely have the most "wood". The "Royal Oak" brand with the US manufactured label seems to be pretty good in that regard. I picked-up a bag last weekend, but haven't done anything with it yet. http://www.nakedwhiz.com/lumpdatabase/lumpbag75.htm
tentacles Posted October 2, 2008 Posted October 2, 2008 Here's a link to the royal oak USA made charcoal review: http://www.nakedwhiz.com/lumpdatabase/lumpbag11.htm - It scored high for burn time, and low for ash production. This charcoal would probably make quite serviceable BP: http://www.nakedwhiz.com/lumpdatabase/lumpbag86.htm Here's a company that makes a number of different charcoals.. including a pine/fir mix. $1/lb isn't bad at all for good charcoal. http://realmontanacharcoal.net/shop.aspx
FrankRizzo Posted October 2, 2008 Posted October 2, 2008 Match Light charcoal would be junk for making BP or star comps. They use a waxy coating on the outside of the briquettes which enables you to more easily light it. However, grinding Kingsford briquettes to near airfloat size, and substituting it for 50% of the charcoal called for in a willow or rocket comp gives *excellent* long-hanging sparks. As Tentacles and I like to say, it's the magic bear turds.
nickle Posted October 2, 2008 Posted October 2, 2008 (edited) I just want to say thank you to tentacles for those charcoal links. I have ordered a few samples from Montana charcoal to see if I can improve my BP. I will post the results and quality of the product when it arrives. Edited October 2, 2008 by nickle
Richtee Posted October 2, 2008 Posted October 2, 2008 I just want to say thank you to tentacles for those charcoal links. I have ordered a few samples from Montana charcoal to see if I can improve my BP. I will post the results and quality of the product when it arrives. No one believes the newspaper route. Sigh. Good charcoal is the "lifestyles" section away.
tentacles Posted October 2, 2008 Posted October 2, 2008 (edited) Rich: It's more that most guys don't want the expense and hassle of cooking their own. Have you seen what they want for an empty paint can these days? They're like 5 bucks! And then fuel, if you (don't /can't) have firewood. Also, there's the small problem of neighbors/fire bans for some guys, too. Edited October 2, 2008 by tentacles
Mumbles Posted October 2, 2008 Posted October 2, 2008 I've also heard conflicting reports regarding newspaper. Some think it's great, others think it's shit. Possibly has to do with locales and paper treatment partly. What tentacles says is true though. Not everyone wants to cook their own charcoal, even though it probably gives the best performance and control.
Mumbles Posted October 3, 2008 Posted October 3, 2008 I've seen reports of straw charcoal, which should be similar to hay I would imagine. It was only partially carbonized, and used in a product called "cocoa powder". It was quite reactive IIRC, but too sensitive to commercially useful.
tentacles Posted October 3, 2008 Posted October 3, 2008 It's way off topic, but peanut shells - if they're broken into bits, would probably make great shell break if coated in BP.
psyco_1322 Posted October 5, 2008 Posted October 5, 2008 I made some of that once, just to see how sensitive it actually was. I even went and pulled some rye out of a wheat field. The only thing is I cooked it clear to charcoal, black as the night. It wasn't any more sensitive than bp that way, I beat the crap out of it with a big o hammer...nothing. But I would imagine that if it wasnt cooked all the way it could be more sensitive.
FrankRizzo Posted October 6, 2008 Posted October 6, 2008 I made some of that once, just to see how sensitive it actually was. I even went and pulled some rye out of a wheat field. The only thing is I cooked it clear to charcoal, black as the night. It wasn't any more sensitive than bp that way, I beat the crap out of it with a big o hammer...nothing. But I would imagine that if it wasnt cooked all the way it could be more sensitive. Yeah, if it isn't cooked all the way, it tends to have "drying oils" (self polymerizing) left on it. These are the types of oils that cause rags to spontaneously combust when finishing fine woodwork. 1
nickle Posted October 9, 2008 Posted October 9, 2008 Thanks to the advice I got from Mumbles and Sidewinder I managed to lunch my first sucessful end burning rocket. This was using the same batch of powder that all the failures came from. I just got a little impatient waiting for my supply of Alder charcoal to arrive. I ran around and scrounged all the BP I had left from the old batch and really rammed the H*** out of it (as per Mumbles). Lit the fuse and stood back and with a screaming sound it was gone, so fast I couldn't keep track of it. I went searching for the remains for about a 1/2 hour and couldn't find anything, no wind to blow it off course but still found nothing. Which leads me to another question. I was thinking of maybe placing a small ammount of kno3/sugar on top of the fuel grain to act as a smoke "tracer" type compound. I would want little or no thrust gererated from the "R CANDY" just smoke so as to see where things are going to land to aid in cleanup of the site. Anyone have any experience with this idea? What ratios for the kno3/sugar mix might be appropriate for this kind of application?
tentacles Posted October 9, 2008 Posted October 9, 2008 You could just ram in some of that KNO3:S:C smoke mix, the stuff that's loaded heavy on sulfur... Sulfur 16 Potassium Nitrate 12 Charcoal Airfloat 1
Pyrohawk Posted October 10, 2008 Posted October 10, 2008 Yeah thats simple enough to do nickle. Just do as ya said....pour some smoke comp in on top of the rocket. You could do it lots of ways...clay bulkhead with a passfire, hell just using the smoke mix right on top of the BP would do fine I'm sure. And with smoke mix your not gonna get any thrust unless you core it. Just play around with it until you find how much smoke ya need for it to come all the way back to the ground.
FrankRizzo Posted October 10, 2008 Posted October 10, 2008 Yeah thats simple enough to do nickle. Just do as ya said....pour some smoke comp in on top of the rocket. You could do it lots of ways...clay bulkhead with a passfire, hell just using the smoke mix right on top of the BP would do fine I'm sure. And with smoke mix your not gonna get any thrust unless you core it. Just play around with it until you find how much smoke ya need for it to come all the way back to the ground. I prefer to top them with a large salute....to destroy the casing and separate it from the dangerous stick of course. It's really all in the name of safety.
Pyrohawk Posted October 10, 2008 Posted October 10, 2008 Hehehe....well yeah so do I Frank...or a nice 3" header. But that won't help him clean up. In fact makes it somewhat worse!
tentacles Posted October 11, 2008 Posted October 11, 2008 But that won't help him clean up. In fact makes it somewhat worse! That depends ENTIRELY on the size and destructive power of the safety device. A good safety device leaves behind nothing but the great smell of sulfur...
nickle Posted October 20, 2008 Posted October 20, 2008 Today I had the second successful launch in a row of an end burning rocket. I used the last of my Cowboy Brand charcoal BP, not really fast. I also put a very small BP salute (firecracker size) on top to test what I have learned here, about passfire to a header etc. Worked perfectly, timing was a little off since it didn't pop until it was on the way down. But it worked!! I have made up a new batch of BP using "Real Montana" brand maple charcoal and this stuff is really fast. Meal powder goes up in just one "poof", should I start from scratch or take what I have already learned nozzle size,tube dia.,tube length and go from there? Just a quick note about "Real Montana" charcoal. The packing could have been better but if the post office didn't mind getting a little dirty it doesn't bother me. I purchased samples of Maple,Birch,and Alder for a $1 a pound. The samples were mixed about 50/50 small/medium pieces and about 95% were completely cabonized, a real steal for the price.
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