usapyro Posted January 6, 2012 Posted January 6, 2012 A mist was starting to form over the fields this evening so I quickly melted some wax and whipped a 200g one together in a foot long tube. With very high dew points the effect is maximized. Even better with a slight atmospheric inversion. Was walking back and forth for nearly ten minutes with the thing on a stick creating a MASSIVE cloud of smoke!!!:lol: With the right atmosphere conditions these things are insane...
Short5 Posted January 6, 2012 Posted January 6, 2012 (edited) Can you share some construction details? I have run into two problems when making them. One problem is they have been very difficult for me to get lit. Most times they don't light the first time, I pour some more prime in the vent and a new fuse to get it lit after it is hot from the first attempt. I usually make a core in it while hot and pour perchlorate and icing sugar mix in as a prime. A second problem has been burn through and flare up. I use spiral wound tube 1.5"I.D. with a 3/16" wall and end plugs made of disks cut from book covers. often a side wall burns through or the vent enlarges because it is charred and weakened from the prime burning in most cases twice. I heat my mixture 60/40/40 kno3/sugar/wax in an electric skillet at 300 degrees. The mixture seems to soften, blend, then the wax starts to separate out. Once I pour it in the case it seems that there is lots of extra wax that I pour off or don't add to the case. Thanks for your thoughts. Anyone else with experience please share your thoughts.. Edited January 6, 2012 by Short5
NightHawkInLight Posted January 6, 2012 Posted January 6, 2012 I've always gotten flare up problems with wax mixtures. I am also interested in construction details.
Short5 Posted January 6, 2012 Posted January 6, 2012 I've always gotten flare up problems with wax mixtures. I am also interested in construction details.I am glad it's not just me. I have made a dozen or so of these and struggled with flare up and ignition problems. My last one I used less wax, sodium silicate on the inside of the case, metal foil on the outside, added silica to the prime, but did not wait long enough for the case to dry. The faster burning fuel ignited and burned like a sugar rocket until the pressure was too much and the end disk blew. Had it not blown I think it would have worked although burned faster than I like. I was frustrated at the time put into it for the results though, even had the end disk stayed in. I kind of gave up on it but still would like to make it work. Has anyone experimented with baking powder as a burn rate modifier? Any ideas what are in the consumer devices like "Mammoth Smoke"? They work pretty well though they flare sometimes as well.
usapyro Posted January 6, 2012 Author Posted January 6, 2012 (edited) Eh... Zero flare problems here. I just use some Al tape to make the nozzle. Wrap it around the end then curl it inward. The Al will flex and open up if there is too much pressure. I preheat my wax and add the thoroughly mixed 60/40 KNO3/S to it. I then scoop it into the tube hot and hammer the tube on the cement with my hand and it settles down inside the tube solidly. For ignition I stick three one inch pieces fuse into it when it's nearly hardened, and then the ignition fuse. Re> Short5I have done KNO3/Sugar/Baking Soda... You can add quite a lot of baking soda and get a nice slow burning mix. However, it is ridiculously drossy and plugs itself up as it burns. Edited January 6, 2012 by usapyro
Short5 Posted January 6, 2012 Posted January 6, 2012 Eh... Zero flare problems here. I just use some Al tape to make the nozzle. Wrap it around the end then curl it inward. The Al will flex and open up if there is too much pressure. I preheat my wax and add the thoroughly mixed 60/40 KNO3/S to it. I then scoop it into the tube hot and hammer the tube on the cement with my hand and it settles down inside the tube solidly. For ignition I stick three one inch pieces fuse into it when it's nearly hardened, and then the ignition fuse. Re> Short5I have done KNO3/Sugar/Baking Soda... You can add quite a lot of baking soda and get a nice slow burning mix. However, it is ridiculously drossy and plugs itself up as it burns. Thanks for sharing your experiences with it. I will try pre heating the wax and adding the mixture. Do you further heat or melt the mixture or just add it to the wax? I should add, I also stick pieces of fuse in my past attempts in addition to the prime and still have had ignition problems.
usapyro Posted January 6, 2012 Author Posted January 6, 2012 (edited) You may need to heat just a little after it's mixed. Another thing you can do for prime is just have 2-3mm of silicon metal/bp prime on top. Put on 1.5mm when the wax is still hot, then 1.5mm when the wax is cooling down. Should work perfect. I use to use KClO4/Sugar to ignite them, but it was a bit too hygroscopic to keep if I remember correctly. I placed the KClO4/Sugar mix in a one inch deep hole made with a small dowel. Edited January 6, 2012 by usapyro
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