powdered sugar rocket problem

[dwhy]

hi everyone,

I tried making a powdered sugar rocket using kno3,powdered sugar and bentonite clay as plug ,and i use a 12.9 cm pvc pipe with 2cm diameter but my rocket didn't lift off, guys please help me with this.

[Bourbon]

What was your formula ratio?

[MadMat]

I didn't finish downloading your video, but poor performance with Rcandy can be due to just a few things. First off, the proper ratio is 65% KNO2/ 35% sugar (it's actually 66/34 but 65/35 works just fine). Secondly, Even though many people use powdered sugar (and get good results), I personally don't care for it because it contains corn starch as an anti-clumping agent. Most importantly though is the lack of proper, intimate mixing. Your KNO3 needs to be ground extremely fine. Ball milling the mixture will likely end up as a horrible clump, that still isn't mixed properly. IMHO, the best way to make Rcandy is to use regular sugar and dissolve the properly weighed out mixture in a small amount of hot water and then boil it down. I use an electric hot plate with a thermostat and an old pot. The idea is to boil out all of the water, but not carmelize the sugar as that will reduce the performance of your rocket. You need to stir and watch this mixture fairly close near the end to prevent carmelization. One nice thing about having a thermostat on my electric hot plate is I set it at 300 F, since sugar doesn't carmelize until around 330F it's safe. Another nice thing about this procedure is there is no need for high pressure pressing of the Rcandy into the tubes. You simply load up your tubes with the melted mixture and give it a little press by hand to make sure there are no bubbles or voids.

Edited January 8, 2021 by MadMat

[SeaMonkey]

An excellent R-Candy Tutorial which goes into several variations.

 

To complement what MadMat has posted above.

[dwhy]

What was your formula ratio?

is 65% kno 35% sugar

[Bourbon]

Between what MadMat and SeaMonkey posted, pretty much covers everything.

 

If you're using powder formula, like mentioned above. Intimate mixing is a must. I'm also, am not a powder sugar fan for this.

 

2 cheap blade mills work great. One for KNO3 and another for Granular Sugar. (((Do not Blade Mill Together))). The blade mill is quick and less likely to ball up like mentioned above "Sugar" with a ball mill. Screen or shake mix as much as you can.

[royster]

Did you stick the rocket stick in the ground?

[SeaMonkey]

I was finally able to view the video and hear the sound of the rocket fuel as it was burning.

 

Something was clearly less than ideal for the uniformity of the fuel mix.

 

Was the Rocket loaded as an End Burner or a Core Burner?

 

Quote from Bourbon:

If you're using powder formula, like mentioned above. Intimate mixing is a must. I'm also, am not a powder sugar fan for this.

 

 

I agree.

 

The Potassium Nitrate must be very finely powdered before mixing with the Powdered Sugar.

 

Some who use this technique will also add a small percentage of Sulfur to the fuel mix.

 

Some will use in addition a small percentage of Charcoal to enhance blending.

 

You may have to experiment more with ingredients and percentages to find a dry powder mix that burns satisfactorily.

 

It can be done.

 

It is also necessary to find a good and safe way to thoroughly blend the mix.

 

Some do this with a Plastic Jar which is filled about half way with the dry ingredients.

 

Then add to the jar four or five lead, brass or bronze balls of about one half inch diameter.

 

Shake or tumble the Plastic Jar thus loaded for a minute or two to thoroughly blend the mix.

Edited January 15, 2021 by SeaMonkey

[Bigfatorange]

hi everyone,

I tried making a powdered sugar rocket using kno3,powdered sugar and bentonite clay as plug ,and i use a 12.9 cm pvc pipe with 2cm diameter but my rocket didn't lift off, guys please help me with this.

. Hey, i really recommend you switch over to paper tubes instead of pvc tubing, you really dont wanna use pvc tubing in pyrotechnics because its really unsafe not only that its worse for the environment. I made the same mistake in the beginning, thankfully nothing bad happened. But hey thats how we learn

[SharkWhisperer]

. Hey, i really recommend you switch over to paper tubes instead of pvc tubing, you really dont wanna use pvc tubing in pyrotechnics because its really unsafe not only that its worse for the environment. I made the same mistake in the beginning, thankfully nothing bad happened. But hey thats how we learn

Unfortunately, almost all of the online video tutorials use PVC piping...

 

Red iron oxide (rust) mixed in at 1% or so is an effective and useful burn rate catalyst.

 

Like others have stressed--intimate mixing is critical. If you're hot-casting (or not) switching to sorbitol instead of sucrose, though a little pricier, will prevent burnt fingertips. Melted sucrose fuel is almost hardened before it is cool enough to handle, giving you a short window for handling, unless you're thinning the viscocity of the hot mix with a little glycerin or sodium dodecyl sulfate (shampoo's main ingredient) as a surfactant and pouring into moulds while still a hot liquid. Sorbitol candy melts at a lower temp and stays putty-like in consistency at temps that your ungloved fingers can easily tolerate. Roll it, stretch it, pack it...you've got plenty of time to work with it, unlike sugar/sucrose candy.

 

Richard Nakka's sugar rocketry site is one you should explore thoroughly if you haven't already.

[stix]

@DWHY: Powdered sugar rockets aren't as simple to make as those youtube videos would lead you to believe.

It would be nice to know what your grain configuration was. Going by that very long burn time, I'm assuming it was an 'end burner'... with no nozzle??

If you want some help on this forum, then it's important to supply as much info as possible, like what methods, tooling are you using etc...

I'm sure most people are more than happy to help you, if you help yourself first.

 

---

 

My favourite sugar motor propellant is KNDX. Dextrose/Glucose powder. I got sick of burning my fingers using KNSU .

I ended up with a nice putty mix which could be easily pressed.

 

The best "powdered" propellant that I ever witnessed was made by my brother. We used to have a bit of a competition, powdered vs melted - lots of fun.

He ball-milled his powdered mix within an inch of its life, then used a huge screw press to pack it over multiple increments. It took ages.

 

The upshot is that it worked great, less residue than my melted version. In the end, we both achieved a specific impulse of around 120secs. The melted KNDX was far easy to make though IMO.

 

@SharkWhisperer: Regarding Sorbitol (KNSB), I while back I made a few small grains using Sorbitol - similar putty method as my Dextrose fuel. Sorbitol is much easier to work with, the only downside is the expense. I'm still yet to insert those grains into a casing for testing. That's if they are still good from mid 2016 .

[SharkWhisperer]

@DWHY: Powdered sugar rockets aren't as simple to make as those youtube videos would lead you to believe.

It would be nice to know what your grain configuration was. Going by that very long burn time, I'm assuming it was an 'end burner'... with no nozzle??

If you want some help on this forum, then it's important to supply as much info as possible, like what methods, tooling are you using etc...

I'm sure most people are more than happy to help you, if you help yourself first.

 

---

 

My favourite sugar motor propellant is KNDX. Dextrose/Glucose powder. I got sick of burning my fingers using KNSU .

I ended up with a nice putty mix which could be easily pressed.

 

The best "powdered" propellant that I ever witnessed was made by my brother. We used to have a bit of a competition, powdered vs melted - lots of fun.

He ball-milled his powdered mix within an inch of its life, then used a huge screw press to pack it over multiple increments. It took ages.

 

The upshot is that it worked great, less residue than my melted version. In the end, we both achieved a specific impulse of around 120secs. The melted KNDX was far easy to make though IMO.

 

@SharkWhisperer: Regarding Sorbitol (KNSB), I while back I made a few small grains using Sorbitol - similar putty method as my Dextrose fuel. Sorbitol is much easier to work with, the only downside is the expense. I'm still yet to insert those grains into a casing for testing. That's if they are still good from mid 2016 .

Dunno, but easy to find out! I've only dabbled in sugar fuels, so no expert at all. But likely they'd store ok if they were dense grains kept dry and out of high humidity. I last bought sorbitol for $9/2-lb bag in Jan or Feb this year, but just checked and the price got jacked to $17 for the same bag in a few months (https://www.amazon.com/gp/product/B08DG4YTFZ/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1). Maybe you could stretch it by mixing with sucrose or other and get some of the plasticity of sorbitol and the cost savings of table sugar? I'm sure somebody's done this somewhere, Nakka would be a good guess, but would need to look into it. Anyways, thanks for the reminder--I've still got half a bag left and a bunch of tubes that need filling!

[stix]

. . . Maybe you could stretch it by mixing with sucrose or other and get some of the plasticity of sorbitol and the cost savings of table sugar? I'm sure somebody's done this somewhere . . .

 

Yep. That's exactly what I did. I mixed it with pure powdered confectioners sugar. Therefore, the sugar is not melted, but suspended in the sorbitol. Burns nice with no residue. It does weaken the structural strength though.

 

I just tested a small strand and it still burns well, but overall I think it has degraded and become weaker in strength after five years - it snapped too easily. Oh well - it's not meant to be kept for a long time anyways.

Edited June 8, 2021 by stix

[SharkWhisperer]

 

Yep. That's exactly what I did. I mixed it with pure powdered confectioners sugar. Therefore, the sugar is not melted and suspended in the sorbitol. Burns nice with no residue. It does weaken the structural strength though.

Hmm....cracked grains could be a problem with compromised grain "strength" and risk catos. Maybe you could carefully up the temperature to sucrose's melting temp if it didn't roast the sorbitol. Might work--sorbitol melts at around 205-210F (95-98C for our Euro and Aussie pals) and will tolerate higher heats without carmelizing, up to about 350-360F (180C). But that's pretty close to where regular old sucrose starts carmelizing, somewhere right around 360F I think, so it might be a delicate balancing act with the heat source. Best results no matter what if you were to screen mix the two together to get super-uniform distribution instead of hot-spots and gradients of one or the other chems. Worth a try. Especially if it stays plastic after it's cooled down quite a bit. I hate messing with regular KNSU because I've scorched my fingertips every time somehow. But sorbitol stays plastic back down to pretty reasonable temperatures where it can be handled without skin loss. And it makes a fine fuel. Trade-off is cost...

 

Erythritol's supposed to work pretty well, too, and it might be a little cheaper than sorbitol. Artificial sweetener in any big grocery store, but could be cheaper online. Gotta read the label because some reduced-calorie sweeteners based on erythritol have other junk in there, too.

[stix]

Hmm....cracked grains could be a problem with compromised grain "strength" and risk catos. Maybe you could carefully up the temperature to sucrose's melting temp if it didn't roast the sorbitol. Might work--sorbitol melts at around 205-210F (95-98C for our Euro and Aussie pals) and will tolerate higher heats without carmelizing, up to about 350-360F (180C). But that's pretty close to where regular old sucrose starts carmelizing, somewhere right around 360F I think, so it might be a delicate balancing act with the heat source. Best results no matter what if you were to screen mix the two together to get super-uniform distribution instead of hot-spots and gradients of one or the other chems. Worth a try. Especially if it stays plastic after it's cooled down quite a bit. I hate messing with regular KNSU because I've scorched my fingertips every time somehow. But sorbitol stays plastic back down to pretty reasonable temperatures where it can be handled without skin loss. And it makes a fine fuel. Trade-off is cost...

 

Erythritol's supposed to work pretty well, too, and it might be a little cheaper than sorbitol. Artificial sweetener in any big grocery store, but could be cheaper online. Gotta read the label because some reduced-calorie sweeteners based on erythritol have other junk in there, too.

.

I agree, I wouldn't use the 5yr old grains either - could be fun though.

 

From memory, the original cast grains were a lot stronger. I think I used 18% powdered sugar - can't remember if that was overall, or 18% of the sorbitol component - I would have to check my old notes. I ball-milled the whole composition before melting. I did lots and lots of tests, and then more testing - that's how I arrived at 18%.

 

I've tried Erythritol and Xylitol, once again I would have to check my notes but I think I had castability issues, so I decided to look into a "putty" type propellant, and that's why I ended up with KNSB. After setting, it stays slightly flexible for a few weeks, which I thought was ideal, but I never got around to an actual motor test.

 

The last sugar I tried was Isomalt, I think I tried it because it wasn't as hygroscopic as the others.

Edited June 8, 2021 by stix