KNo3+Sucrose questions

[Penfen]

Months ago after I saw some YouTube videos on rocketry I decided to just jump right in and try making a rcandy mixture, but I realize now that what I did was probably pretty dangerous. I just put the sucrose and KNo3 mixed together in the frying pan, and heated the mix until it was caramelized. The stove was actually broken, so each element would heat to different temperatures even though the temperature controls would be set at the same positions. I didn't really know what I was doing and this was done inside my kitchen... I wasn't using real protective gear, a crappy mask and glasses (rather than goggles.). I saw this one video of a mix blowing up on a stove and the guy didn't have any time to react, so I mean, if this went off in my kitchen with me leaning over it I would have probably had my face burnt and wouldn't have been able to put the fire out (it burns under water doesn't it? Plus the kitchen would have been filled with smoke so I wouldn't have been able to see what I was doing even if I wanted to put the fire out.

 

Anyway, I'm thinking of making more of the rocket mix with the left over KNo3, but I have some questions:

How exactly am I actually meant to heat the two together? I get that KNo3 melts at 334°C and sucrose melts at 186°C, so I think that the idea is that you melt the sugar only, and by melting the sugar, this will increase the contact the sugar has with the KNo3, making for a better burn. Would there be much less contact if the two were just mixed together dry?

 

At what temperature does this mixture ignite in the pan?

 

Could I melt the sucrose on its own and just mix it in with the sucrose after, or should they be done together?

 

Should I use water? One guide I read said that you should equal the mix in mLs (e.g. 100g mix, 100mL water.) If so, do you wait for all the water to evaporate after it boils or do you just strain the mixture out of the water?

Does dissolving the mix in water do anything to the potency of the mix or just make it less likely to ignite?

 

Safety:

I'll be doing this outside on an electric hotplate (could I use an electric frying pan? One guide said that the teflon on non-stick pans is unsafe), with protective clothing, a mask, and good goggles.

Edited February 23, 2012 by Penfen

[dagabu]

Months ago after I saw some YouTube videos on rocketry I decided to just jump right in and try making a rcandy mixture, but I realize now that what I did was probably pretty dangerous. I just put the sucrose and KNo3 mixed together in the frying pan, and heated the mix until it was caramelized. The stove was actually broken, so each element would heat to different temperatures even though the temperature controls would be set at the same positions. I didn't really know what I was doing and this was done inside my kitchen... I wasn't using real protective gear, a crappy mask and glasses (rather than goggles.). I saw this one video of a mix blowing up on a stove and the guy didn't have any time to react, so I mean, if this went off in my kitchen with me leaning over it I would have probably had my face burnt and wouldn't have been able to put the fire out (it burns under water doesn't it? Plus the kitchen would have been filled with smoke so I wouldn't have been able to see what I was doing even if I wanted to put the fire out.

 

Anyway, I'm thinking of making more of the rocket mix with the left over KNo3, but I have some questions:

How exactly am I actually meant to heat the two together? I get that KNo3 melts at 334°C and sucrose melts at 186°C, so I think that the idea is that you melt the sugar only, and by melting the sugar, this will increase the contact the sugar has with the KNo3, making for a better burn. Would there be much less contact if the two were just mixed together dry?

 

At what temperature does this mixture ignite in the pan?

 

Could I melt the sucrose on its own and just mix it in with the sucrose after, or should they be done together?

 

Should I use water? One guide I read said that you should equal the mix in mLs (e.g. 100g mix, 100mL water.) If so, do you wait for all the water to evaporate after it boils or do you just strain the mixture out of the water?

Does dissolving the mix in water do anything to the potency of the mix or just make it less likely to ignite?

 

Safety:

I'll be doing this outside on an electric hotplate (could I use an electric frying pan? One guide said that the teflon on non-stick pans is unsafe), with protective clothing, a mask, and good goggles.

 

Yes, start out with a full face shield, it is as you say, a flash fire issue where copious amounts of heat are created almost instantly and there is no time to react plus when doing this outdoors, winds shift and you may have the plume directed right at you. Yes, use water to dissolve the sugar and KNO3 in the fry-pan and set the temp to 400°F (200°C) so that the sucrose can melt and caramelize. A full kilo of KNO3 can be dissolved into a liter of boiling water and 2000g of sucrose can be dissolved in a liter of 25°C water.

 

66% KN, 34% Su is the theoretical best mixture so if you heat up 1L of water to boiling and put 660g of KNO3 into the water (go slow) and dissolve it completely, then take the sucrose (340g) and add that to the hot water to completely dissolve it you will have a base for making R-candy. I find that the mix heats faster then dry melting, (1/2 the time to get R-candy) it is faster burning and it is workable longer when pouring it into tubes.

I strongly suggest that you follow Jackob's Rocketry guide to make your R-candy.

-dag

[THEONE]

It is MUST to use any kind of syrup (glucose, fructose, corn syrup) to do a r-candy

Watch

carefully until you have completely understand what he is doing

 

Also recrystallized method is good for small motors cause it takes a lot of time to prepare it, if you in the future going to built any bigger motor (J-K-L) use Dan Pollino's flexible fuel

 

Here is a video on how to cook flexible fuel

 

Also the sugar MUST NOT starts to caramelize... (do not ask why )

Edited February 27, 2012 by THEONE

[dagabu]

It is MUST to use any kind of syrup (glucose, fructose, corn syrup) to do a r-candy

Watch

carefully until you have completely understand what he is doing

 

Also recrystallized method is good for small motors cause it takes a lot of time to prepare it, if you in the future going to built any bigger motor (J-K-L) use Dan Pollino's flexible fuel

 

Here is a video on how to cook flexible fuel

 

Also the sugar MUST NOT starts to caramelize... (do not ask why )

 

Not so. R-candy may be used without any syrup when individual inhibited grains are used. Cracking is much less an issue where the grain is no more then X1.5 it's length. Also, there are many motors where a caramelized fuel is useful for as the burn is much longer and the thrust is much lower. I have used it for seconf stage sustainers where a good white smoke trail is needed in the coast phase of flight.

 

-dag

[mahoo91]

Apologies if this is the wrong thread to post this question on. I have had some success using rocket candy in rockets, using a 35:65 dark powdered sugar and potassium nitrate "cooked" into a solid and inside a foil lined tube. My problem however has been the temperature that the mixture burns at. I have been adding small charges to the end of my rockets using flash powder (im not new to pyrotechnics in general just to rockets) with Chinese time fuse as my delay through a bentonite barrier at the end of my propellant but every time i try it results in a premature explosion and a cloud of smoke presumably from the rocket candy igniting. Iv tried using baking soda as well as a few commercial inert powders to slow the reaction but this reduces the thrust too much and the rocket won't leave the ground (i don't add FP during tests but a small black powder charge that burns in a small paper ball). Or if reducing the temp of the reaction isn't feasible without vastly reduced thrust does anyone have a suggestion for a lower burning temperature fuel?

[val77]

for a best rcandy fuel ballmilled 65 gramms of kno3 and 35 gramms of sugar

after milled 4 hours add a tiny pinch of fe203 (red iron oxyd)

your rcandy should be pink;)

Edited October 27, 2012 by val77

[shagaKahn]

val's advice is perfect; you can have a blast (uh, use a different word) with sugar rockets and never have to hazard cooking the comp.

 

My experience has been with sorbitol as the fuel but I NEVER cook candy fuel anymore. Just mill my comps thoroughly in a mortar and pestle then carefully and patiently mix them (cold and dry) then use a conventional BP rocket tool set and ram some motors. (My set is for 4 oz BP rocket motors; came from Skylighter--and that's right: you don't HAVE to use BP.)

 

Have made half a dozen or so and they fly like hell and so far no CATOs. Val's tip to add some red iron oxide results in delicious orange sparks.

[val77]

thank you shaga

it is especially when your rcandy is powder, you can easily use your rocket black powder tools

and if your powder is very fine, you do not need to iron oxide