Rcandy Not working properly

[dagabu]

Steve,

 

Firework Tools is out of business, the link is dead.

[stix]

Is the melted method just 2 parts oxidizer and 1 part fuel, no water? If you use really pure KNO3 and sugar do you avoid caramelization, or just counter it with iron oxide?

 

Yep Yoyo, that's pretty much the standard formula I use:

 

65% / parts KNO3

34% / parts Sucrose

01% / part Red Iron Oxide.

 

No Added Water.

 

If you want fast burning fuel, it's best to ensure that your KNO3 is powdered as fine as you can - I use a coffee grinder. Otherwise the fuel will burn slower because the mix will not be as integrated - the burn rate will depend on the particle size of the oxidizer - the sugar will melt around the particles.

 

Sugar melts at around 186C, so be careful not to burn yourself (I have, ouch!!!)

In my experience the RIO has nothing to do with countering caramelization - it's purpose is to speed up the burn rate of the fuel - by a significant amount!

 

The only way to avoid caramelization is to work fast and have a good electric frypan/skillet - which is one of the reasons I switched to Dextrose/Glucose powder.

 

The KNSU+RIO fuel I have made in the past has worked extremely well. Although not as fast as good BP, a small piece, say 4mm cubed will easily take off by itself when lit - BE VERY CAREFUL and start small. Use eye protection at the very least - best to test it using a fuse or a common sparkler from at least 10mtrs or so.

 

 

why don't you guys add corn syrup, its the binder for this mix , I hear people are getting a much more consistent burn rate and the fuel isn't as crumbly.

As for why cast it rather than ram it? that's an easy one I can spend 100$ and make 15 or so K engines , and not have to get a press and special custom tooling to press it .

 

Stay Safe and Stay Green

 

~Steven

 

Hi pyro, I've used corn syrup / glucose syrup in past experiments to success - my issue is that the burn rate is inconsistent because it contains water, therefore it will always be difficult to determine how much water is left after cooking.

 

I was testing using a load cell and good software, so I know the difference. It's all about tolerance, ie. what you are prepared to accept as a consistent usable, reliable fuel. I was into model rocketry at the time, so it mattered.

 

+1 about casting - much easier and quicker to get something off the ground than pressing.

 

Cheers.

 

[EDIT] Reason for editing: I accidentally dropped my ciggy on the keyboard - after a bit of a flurried panic, I unfortunately hit the friggin keys which sent the post - could also be beer soaked as well -- all fixed now . . . I think . . . Good thing though, as I think I've fixed all my spelling mustikes.

Edited November 12, 2014 by stix

[yoyo]

Thanks stix, I will try your formula. You're right about the corn syrup - most of my rocket tests have either been not powerful enough or too powerful, because until I learned about the snap test it was hard to tell when it was ready.

 

In the melted mix - do you stir in the iron oxide when the glucose/KN mixture has fully melted, and is the mixture pourable when ready?

[Ubehage]

Thanks stix, I will try your formula. You're right about the corn syrup - most of my rocket tests have either been not powerful enough or too powerful, because until I learned about the snap test it was hard to tell when it was ready.

 

In the melted mix - do you stir in the iron oxide when the glucose/KN mixture has fully melted, and is the mixture pourable when ready?

You melt it all mixed together.

I won't call it pourable. More like workable

[AzoMittle]

Melting mixes chems on molecular level, makes grains stronger, and more consistent in terms of burnrate and density.

 

 

Would it be beneficial to cast a puck of R-Candy and then granulate and press into the tube? By doing this we would get the benefits of melt-mixing without the problems of melt-casting (cracks/voids in grain, having to work quickly before it cools, case bonding/waxing, additives that can't be heated, etc)

 

Edit: As far as (Red) Iron Oxide goes, I recall it increases the performance as pressure increases. I cannot find anything on this now but I would put $5 that I did read that somewhere at some point (not to say it is correct...)

Edited November 14, 2014 by AzoMittle

[ChemMork]

If you want smth castable i would replace the normal sugar with sorbitol! Sorbitol melts at 95°C and the mixture can be poured easily

[stix]

Thanks stix, I will try your formula. You're right about the corn syrup - most of my rocket tests have either been not powerful enough or too powerful, because until I learned about the snap test it was hard to tell when it was ready.

 

In the melted mix - do you stir in the iron oxide when the glucose/KN mixture has fully melted, and is the mixture pourable when ready?

 

I combine all the dry ingredients first in a small plastic container, lid on and shake for about 2 minutes.

 

When I put it into the frypan on low heat (before melting) I stir it around with a wooden flat blade spatula - when it starts to melt, and during melting, I'm always constantly stirring the mix. This method has always yielded consistent results.

 

KNSU is sort of pourable but only if you mix large amounts as it would retain more heat. You should be able to scrape it when liquid into your mold though a hole in the base.

 

I make bates grains. I need the fuel to burn slower, so I don't use KNSU+RIO anymore, I use KNO3 + glucose powder (dextrose). This mixture is NOT pourable. When soft like plasticine, I roll up small balls and hand ram them into my mold using a cold metal rod.

 

If you are making 'end burners' the addition of RIO is absolutely beneficial.

 

My current formula for bates grains is:

 

65% / parts KNO3

35% / parts Glucose Powder (Dextrose)

 

Happy to give you some further info if you're interested.

 

 

 

 

Would it be beneficial to cast a puck of R-Candy and then granulate and press into the tube? By doing this we would get the benefits of melt-mixing without the problems of melt-casting (cracks/voids in grain, having to work quickly before it cools, case bonding/waxing, additives that can't be heated, etc)

 

Edit: As far as (Red) Iron Oxide goes, I recall it increases the performance as pressure increases. I cannot find anything on this now but I would put $5 that I did read that somewhere at some point (not to say it is correct...)

 

Red Iron Oxide increases the burn rate regardless of the pressure. Try a test under ambient pressure, with and without it.

 

I've heard that others make r-candy granules and press later. Sounds good, but you need a decent press. I've tried this method twice, but only rammed with a hammer - CATO!!. due to cavities I suspect. I'd rather not have to use a press, hence my current fuel and methods.

 

If you want smth castable i would replace the normal sugar with sorbitol! Sorbitol melts at 95°C and the mixture can be poured easily

 

Yep, Sorbitol sounds like the ultimate sugar to use, as in low melting point. Unfortunately it's hard get and very expensive in Australia. I read somewhere that the US FDA has limited it's use due to health side effects? Bastards they are

 

Other alternatives I have trialed are Xyltol (melts at 92C) and Erythritol (melts at 121C) - Never had great success, but that was when I started out making r-candy so perhaps my methods are better now and could be revisited.

 

Cheers.

Edited November 14, 2014 by stix

[yoyo]

AzoMittle - I tried that once. It depends on the consistency of your cooled r-candy. The stuff made with corn syrup is pretty solid; it was like grating a rock. The result burned too slowly.

[pyroman2498]

 

 

Would it be beneficial to cast a puck of R-Candy and then granulate and press into the tube? By doing this we would get the benefits of melt-mixing without the problems of melt-casting (cracks/voids in grain, having to work quickly before it cools, case bonding/waxing, additives that can't be heated, etc)

 

Edit: As far as (Red) Iron Oxide goes, I recall it increases the performance as pressure increases. I cannot find anything on this now but I would put $5 that I did read that somewhere at some point (not to say it is correct...)

 

I have tried this and have had Ok results but I find casting it easier , but if you want to press a rocket use just Kno3 and sugar ball milled ( or just get both as fine as you can ) and press it , I have had good , powerful nozzless rockets , they give a nice ROAR!!!! when taking off and get to a decent height. casting is only good for making grains for high powered rockets , or casting one giant K engine .

 

Stay Safe and Stay Green

 

~Steven

[stix]

 

... if you want to press a rocket use just Kno3 and sugar ball milled ( or just get both as fine as you can ) and press it ...

 

Yep, I can confirm the merits of this method. A friend of mine ball mills his mix to an ultra-fine powder then presses it using a decent shop press. He has achieved the same measured results (load cell) to my melted method.

 

One reason I don't like this method is that it takes too long to press as it has to be done in small increments to ensure it's solid. Whereas I can spend an afternoon making many bates grains, store them and when required simply 'hammer ramm' a bentonite nozzle, insert a couple of grains, a header, and I'm good to go.

 

One interesting thing about his 'pressed powder' method is that it doesn't seem to become hygroscopic!... don't know why.

Edited November 20, 2014 by stix

[dagabu]

Add a little real corn syrup and it will stay flexible longer and not crack when pressed into a single grain. It's also a lot easier to shred if you like to make R-Candy rockets on regular BP tooling.

[captainG]

Do you have an exact formula with the corn syrup dag?

[dagabu]

Sure!

 

65% Potassium Nitrate

15% Sucrose (Powdered Sugar)

19% Corn Syrup

[captainG]

Thanks, I'm assuming the liquid is by weight as well huh?

[Ubehage]

Thanks, I'm assuming the liquid is by weight as well huh?

Yes

[webski]

OK so I had to revist the Recrystalized method. I wanted to pour (cast) some smoke bombs and also try some for 3/4" rockets.

I made two batches. One 65/35 standard Mix for a smoke composition poured/cast into TP tubes. It turned out OK.

The idea was to make a smoking firestarer that would get rid of the bugs for a bit and then start a nice wood fire in my fire pit.

I have not tried it yet as I have to head north to my cabin this weekend.

 

The second batch intended to be rocket fuel had a 65/15/19 ratio of powdered KNo3 and powder sugar and corn syrup disolved in water and boiled off and then 2% RIO added.

It turned out very sticky and hard to work with . I did manage to pack two rocket tubes and had a bunch of sticky goo left over that was put into a paper cup and allowed to harden. The rocket mix did not fully harden and it was very hard to remove the coring spindle.What a mess.

 

What did I do wrong ?

and Is there any way to dry out and harden the rocket mix ?

or should I just abandon this idea ?

 

Maybe I'll just stick to dry mix where I've had reasonable success...

 

IDEAS ? solutions ? thanks !

[schroedinger]

Are you sure you really boiled of all the water?

[stix]

Seems like a bit too much corn syrup and as schroed's pointed out - make sure all the water is driven off.

 

Glucose powder if you can get some is much easier to work with as it melts around 145C.

 

[EDIT] Sorry, just realised you are doing the re-crystalized method. May I suggest you purchase a coffee grinder and powder your KNO3, then the glucose/dextrose powder, and melt it. Much quicker and easier to handle than sucrose - no more half burnt fingers

Edited June 24, 2015 by stix