Sciencemadness Discussion Board

Need info on KClO4 propellants

Intergalactic_Captain - 17-10-2007 at 12:51

Not sure if this belongs here or in miscellaneous, so mods take note and move if necessary...

Anyways, I'm in need of a relatively cheap, high-impulse fuel for 3/4-1" ID x 4-8" long core-burning rocket engines. NH4ClO4 composites seem to be the propellant of choice for high-impulse engines, but cost constraints are leaning me towards KClO4 instead.

I have been able to find surprisingly little information on this material as an oxidizer...Short of early JATO development, there is not much info out there and even less on fuels other than asphalt. Urbanski gave a few references that I need to check, but a look at their titles doesn't seem to indicate that they'll help me out.

One of the things I'm considering is a high-melting paraffin wax as a fuel, but the only thing I've been able to find is NASA reports on its use in hybrid LOX rockets. Another possibility is epoxy resin, though this would push me into the "rediculously expensive experiment" range.

So, anyone have any references and/or first-hand experience on the use of KClO4 as a rocket oxidizer? Note, I am well aware of whistle-mix and would rather avoid it...Not that it's particularly expensive, just that it's not really suited for nozzled rockets and happens to "whistle" rather than "whoosh."

NH4ClO4

MadHatter - 17-10-2007 at 15:18

KClO4 works well with many fuels, except powdered metals. I would suggest trying to
prepare NH4ClO4 from either sodium(recommended) or potassium perchlorate.
Again, KClO4 will work with a lot of fuels but the "whistlers", benzoates, are my favorites.
I do prefer them over the sucrose/KNO3 fuels because of their increased performance
and their distinctive sound. But to each his/her own. Good luck on your fuel search.
It's really a matter of experimentation and what your goals are. BTW, wax would make
a good fuel for your application. I can't say that I've seen references on it though. This
is just from personal experience.

chemkid - 17-10-2007 at 15:25

How would one either go about aquring or synthesizing pottasium or sodium perchlorate? Furthermore, what sort of safety measures would one take with such oxidizers?

chemkid

Xenoid - 17-10-2007 at 15:50

Quote:
Originally posted by chemkid
How would one either go about aquring or synthesizing pottasium or sodium perchlorate?


Hmmmm... This endeavor seems to be the subject of the most and the longest threads in this forum...:o

Note: A few perchlorate compositions are given by franklyn in this thread;

http://www.sciencemadness.org/talk/viewthread.php?tid=8746

Regards, Xenoid

[Edited on 17-10-2007 by Xenoid]

[Edited on 17-10-2007 by Xenoid]

Mr. Wizard - 17-10-2007 at 16:45

I remember reading about perchlorate and asphalt pitch being used as a solid rocket fuel in the past. It was mentioned in some amateur rocket book in the mid 1960s. I think it was called Galcit. I'll leave you to do the searches.
A side note is the DOW Chemical company which got it's start manufacturing Bromine to fight Typhoid in wells, decided to use asphalt covered wood as containers and cells to make the Chlorine needed to free the Bromine from brine wells. They actually got rich using the products made from the left over Chlorine.

Intergalactic_Captain - 18-10-2007 at 08:59

Yeah, I checked out the Galcit stuff...Seems to be just KClO4/asphalt. Once the team discovered NH4ClO4, they took off in a different direction (thiokol and rubber/plastic binders and fuels). I think I'll probably focus on wax - No literature, no patents (at least none since 1976, anyone got a better searchable database than the USPTO?) - Only thing I can find is posts in various forums hinting that it might work. So, I'm calling this one - If anyone patents this one before I do, know well that I'm not above hunting you down and hammering your kneecaps in ;).

Anyways, I figure wax will probably be slow burning and hard to ignite. Ideas thus far are use of an iron oxide catalyst for enhanced burn rate and possibly aluminum powder to enhance ignitability. Should the aluminum be too much, I'm considering having a thin layer of al-enhanced fuel in the core, with the main fuel grain around it... ((({O}))) where () is the main grain, {} is the al-enhanced layer, and O is the hollow core...Should light easier and spread the flamefront faster, but the pressure spike might lead to CATO's.

Oh, and thanks for the little side note on DOW - I knew about the low-tech bromine thing, but I didn't realize it was the antibacterial market for chlorine that drove them...I was under the assumption that they were focusing on bromine, not unloading it as a byproduct.

Mr. Wizard - 18-10-2007 at 09:57

They got their start making Bromine for the anti-typhoid market. They used a brine well to get the raw material. To make the Bromine they had to make Chlorine, they then had excess Chlorine; for which they then developed a market. Even though Chlorine is the most common disinfectant now, then it was too hard to store and contain. Bromine had the advantage of being a liquid and a few drops down a well would sterilize the water. Now doubt it sold quickly after a few of your neighbors died of typhoid. Store keepers could keep a shelf of it handy for impulse (panic) buying.

Candle makers have a special tough wax they use on the outside of candles. It almost feels like plastic, but it melts and can be used for candles. Maybe it would be a better option than plain paraffin wax?

Intergalactic_Captain - 18-10-2007 at 10:44

Ahh...That story makes a bit more sense now.

Any idea what this outer wax is called? I know what you're talking about, just no idea what to search for. I was thinking about using a high-melting wax, like used by sculptors to make positives for molds. Some of the NASA articles alluded to "hurricane candles," though I'm not exactly sure how a high-melting wax would have anything to do with the wind resistance of a naked flame...Maybe it just lasts longer than standard paraffin wax. In the meantime, I've got quite a bit of mason-jar sealing wax, though I'm not sure how well it'll stand up to the temperature of a 3000degC flame.

Mr. Wizard - 18-10-2007 at 16:12

The wax used by sculptors is most likely the 'lost wax' used in jewelry and denture making. It is very hard. I don't know what the hardened out wax is called, but it may be an admix called Vybar 103. Any candle makers out there?

Twospoons - 18-10-2007 at 17:09

There's always NH4NO3 with Mg, and a HTPB binder as outlined in this book..

CP Technologies

I've got the book, and it is very detailed with regards to formulating and testing nitrate based propellants. Also covers motor design - but given the nature of your question you probably know about all this already.

artem - 20-10-2007 at 11:06

Quote:
Originally posted by Intergalactic_Captain
I have been able to find surprisingly little information on this material as an oxidizer...Short of early JATO development, there is not much info out there and even less on fuels other than asphalt...

There were some references about KClO4 in early solid propellants:
1)ALT-161 (Aerojet jato): KClO4 76%, bitumen(asphalt) 16.8%, oil 7.2%. Jsp=173, d=1.77, u=1.29*P^0.7(mm/s, P -bar)
2)KClO4 76.5%, bitumen 23.5%. Jsp=186(140bar), d=1.77
3)"Basuka": KClO4 76.28%, HPTB 21.94%, castor oil 0.9%,additives 0.48%
4)KClO4, graphite, binder, 8%Ti
KClO4 isn't well enough as a rocket oxidizer (smoke, sensitivity, low Jsp), so it was not used widely. I think, it can be used with any available binder, and part of the binder can be changed by cheap fuel (C, sugar, etc)

Bert - 20-10-2007 at 20:09

Quote:
Originally posted by Intergalactic_CaptainSo, anyone have any references and/or first-hand experience on the use of KClO4 as a rocket oxidizer? Note, I am well aware of whistle-mix and would rather avoid it...Not that it's particularly expensive, just that it's not really suited for nozzled rockets and happens to "whistle" rather than "whoosh."

Steve Laduke has made "hybrid" whistle rockets with the whistle mix de-tuned by the admixture of charcoal and/or other black powder ingredients. They don't whistle, can be made as cored, choked rockets similar to BP configuration but with considerably higher specific impulse. There was an article in the PGI bulletin recently, and Rich Wolter makes tooling for these motors.

dann2 - 21-10-2007 at 04:49

Hello,

Not too well up in the rocket fuel business myself.

The Galsic was used (amongst other places) in JATO units.
(Jet Assisted Take Off). It would be more correct to have called it rocked assisted take off but back in thosed days rockets were referred to as jets. I guess the jet engine was still in its infancy.
The JATO units were rockets strapped to planes. Theses rockets worked at hugh pressure and the walls of the rockets were very thick (and heavy). The empty rocket motors were dumped at the end of the runway (or shortly after). The thick walls/heavy containers suited the application as the rocket was being asked to push only.
What I am trying to say is: I think K. Perchlorate suits very high pressure applications, not too sure though.

I have a formula somewhere that describes using Bakelite (Phenyl Formaldehyde) + Perchlorates as a fuel. The whole thing is fairly easy to make. Will dig it up. I think it was end burning. East to pour and solid setting.

Wax:
Regarding wax as a fuel I heard of a guy who had good success using it with K. Chlorate (He probably did not have Perchlorate) in small pryo tech. rockets. Endburning.
He melted the wax and Chlorate. I believe this is fairly safe with wax.

An idea I have had going around around in my head for a long time for using wax as fuel is this:
In order to avoid having to melt the wax, ball mill it.
I would hope that wax would ball mill successfully if put into a ball mill (huh!) and then the ball mill but into a deep freeze.
The hope being that the wax would be brittle enough at this temp. to ball mill into a fine powder.
This could then be mixed at low temp. with the oxidizer and squeezed/ pressed into motor. Heating to approx 50C would then bind the lot.
Might work, might not.

Dann2

Phonol-Formaldehyde + KClOx

dann2 - 21-10-2007 at 16:34

Hello,

A Bakelite + KClOx propellent.






Making the resol is relatively easy but if you want to make this king of propellent on a regular basis you need some sort of Vacuum pump
+ chamber and heater (inside the vacuum chamber). It is however possible to make a sstisfactory resol without a vacuum system but the resol takes a lot
longer to cure.
Note Phenol and Formaldehyde are poisonous and this procecure should be carried out in the open. Once the initial reaction is over and the syrupy
stage is reached then the stuff is relatively harmless (apart from flammability).

Method
Add 20g of Phenol and 0.5ml of 40% NaOH solution to 40ml of 37% aqueous Formaldehyde solution (Formalin). Bring to the boil and boil untill the liquid
becomes noticably thicker (typically in the order of 10 minutes). If you stop too soon it will take forever to cure the resin, if you wait too long it will beocme too
viscous to mix with the oxidizer (like toffee) or even become fully cured in whatever vessel you were boiling it in. You might be able to salvage it with alcohol.
The resol is removed from the heat and 108g of KClO4 or 125g KClO3 is stirred in. The resultant is poured or pressed into a mold/casing. Try your utmost
to get rid of bubbles at this stage. The grain is cured by placing
it in an oven at around 50C or so for about 12-24 hours. The temperature is slowly increased untill the resin sets rock hard at a final temperature of 120C or so. <BR>
If you increase the temperature too quick big bubbles will form in the grain.. The first cool part is mostly to allow excess water to evaporate., the actual curing
takes place at the higher temperatures. A resol that has been dried in a vacuum can be cured somewhat faster.



Never tried the above propellent myself BTW.



Dann2

Boomer - 22-10-2007 at 07:19

After "re-inventing" candy propellant for a science fair project around 1980 (it was known but not to us), we upgraded to NaClO3 (reX'ed from weedkiller, 2 Dollars per kilogram at the drug store - good old times). There was no way we would melt-cast chlorate/sugar, we knew what a kilo did to a fire extinguisher! (Do that now and you are put away as a terrorist.)

We had little luck with asphalt/oil but were afraid to use only asphalt (tar) since it melted too high for our taste to add a chlorate.

Ended up with 75% chlorate and 15/10% tar/wax, this can be processed in a water bath if you start with the (normal candle-)wax alone. Using only wax might pose the danger of it melting in bulk, something opaque prevents the heat radiation from penetrating the unburned fuel too far. This was a guess but we wanted to be safe.

BTW why is epoxy "rediculously expensive"? 15 bucks a kilo, and you need 20% max, i.e. 3 dollars per kilo for the binder, so the oxidizer will most likely cost you more.
A 3/4" rocket will hardly need 100g fuel, which means epoxy for 30 cent!

dann2 - 22-10-2007 at 16:35

Hello,

Careful with the tar/asphalt. I think it is frowned upon (a no no) with Chlorate.

Dann2

Twospoons - 23-10-2007 at 16:30

The evil thing about epoxy is the exothermic cure. A cupful of laminating epoxy will all but catch fire as it cures. (Yes, I've tried it :D ) You need the slow cure type, used for potting.
Urethane could be a possibility, its a cold cure.

DeAdFX - 23-10-2007 at 19:39

You could try KClO4/PVC/Hexamine/Plasticizer like an ester. Find some Gorilla glue. It contains 85/15 solvent/PVC resin. You could try other types of PVC cements as they contain various combustible resins like polyester or Acrylic Butadiene styrene (ABS) resin. I am pretty certain they will dry up like a rock so a plasticizer would be an excellent idea.

Bert - 27-10-2007 at 08:16

Gorilla glue is a urethane and cyanoacrylate mix AFAIK.
http://gorillaglue.com/UserFiles/MSDS%20Stronger%20Faster%20...

You don't want a grain full of bubbles, unless you WANT to have a CATO. Gorilla glue foams as it cures...

You don't want any type of volatile that leaves the fuel as it cures, causing shrinking and leading to voids- CATO again.

You might want to check out GE silicone sealer. Several have made rockets with this, as well as go getter type stars.

Or you could bite the bullet and go find some HTPB or PBAN.

halogen - 27-10-2007 at 13:29

"You don't want a grain full of bubbles, unless you WANT to have a CATO. Gorilla glue foams as it cures..."
And a good deal at that.

LDPE (Low Density PolyEthylene) might be a possibility. Melting point is 120*C, and it is apparently available as 'six-pack soda can rings'. This looks like a useable material, though I can see no reason wax shouldn't work. The only advantages, if any, of LDPE are that while one normally would buy wax, one can rummage in the garbage/recycling receptacle, and that LDPE would be more standardised as to exact composition.
In either case, additives are your friend. Wax melts easily, which might cause some difficulties in ignition, and during flight, possibly warping your core, a bad thing. Here, perhaps lampblack or such would be advisable. To aid combustion, and raise the internal heat, a bit of aluminium is a possibility (though not too much, mind you). Also, a catalyst such as very fine Fe2O3 is advisable.

Microtek - 28-10-2007 at 02:44

I experimented with LDPE fuel/binder with KClO4 some time ago. The propellant was very energetic, but quite hard to process. I used Fe2O3 as catalyst.

halogen - 28-10-2007 at 06:03

Do you recall any particular percentages?
EDIT 'particular' has an 'i' in it...

[Edited on 28-10-2007 by halogen]

Microtek - 29-10-2007 at 08:59

I just used enough KClO4 to oxidize the carbon content of PE to equal parts CO and CO2. I chose this mix because it gives good results with candy propellants (the rule about enough oxygen to produce equal parts CO and CO2, that is). Afterwards I just added a pinch of Fe2O3 to the finely powdered KClO4. The LDPE I used was in the shape of PE-film.
I made a lamellar wafer consisting of alternating layers of PE-film and oxidizer/catalyst. Then I heated it on a hot-plate and kneaded it until uniform. Finally it was loaded into a die to cool and solidify.

halogen - 29-10-2007 at 13:09

Sorry for the bombardment of questions, but I'm thinking of trying this one. If you can't recall, that's perfectly fine.
Did the batch size make any difference (this actually matters as I was surprised to discover with another mixture)?
What temperature (approx of course) at and for how long did you heat it?
What were its solid properties (i.e. how hard was it)?

Microtek - 30-10-2007 at 01:12

The ratio was what I wrote in the above post:

2 (CH2)n + 1.25 KClO4 --> 1.25 KCl + CO + CO2 + H2O

Meaning 28 g PE to 173 g KClO4.

I only made one batch and that was very small; in the order of 5 g. As for temperature, well my hot-plate is actually an iron (as in the household appliance) and doesn't list temperatures. But since PE melts at around 120 C I would guess that I heated it to maybe 150 C. Then I just kneaded it on the hot-plate using a stainless steel spoon until quite uniform. Due to the high solids load (86%) the mix is very stiff when molten, so you can't actually stir it. Instead you press the mix into a flat sheet with the spoon and then fold it over a few times, then flatten it again for however many times it takes. Maybe it would be easier if the batch was much bigger.
When it cools off, it gets very firm (much like solid PE in fact) but a little more crumbly than pure plastic.
BTW, I tried this type of binder in combination with nitramine explosives (HMX mostly but also some RDX) and it really works quite well as PBX-type charges.

Twospoons - 30-10-2007 at 17:10

Hard waxes for investment casting can be made by mixing PE with paraffin wax. Adding a little wax to the PE might make it easier to incorporate the oxidiser.

Intergalactic_Captain - 30-10-2007 at 20:11

Wow...didn't think this would prove to be such a popular thread.

Microtek - I like the idea with the PE binder. This was actually one of my earlier ideas, but I was thinking more along the lines of PET/PETE (same thing, but only the patent holder can call it PETE...or PET...interesting story though). Did you try any solvents, or just jump straight into the softened mixing method? How'd it work without the Fe2O3?

Boomer/Twospoons - The epoxy discourse is interesting. I hadn't thought about the heat being an issue, but for the size I'm looking at it definitely would be. As for cost, per engine it might work out but development would be insane...$30/gallon for something decent, with no indication of its properties for this application - Raw cost would be anywhere from $30-100/gallon, not something I want/have the time to mess with right now.

Bert/DeAdFX - The gorilla glue sparked my interest, but I've got a bottle of it at home and use it quite often...If anyone can figure out how to eliminate the bubbles or extract the active ingredient, hats off to you. As a side note, it does make a nice sealing and gasketing material - Don't use it with ethanol, though...softens and dissolves it for some reason.

Dann2 - I like the bakelite idea, but the only way I could do it is through a chem supplier or some other online source...Factor in shipping and it's too much (for now, I do plan on trying it in the future). On a side note, have you done anything with a GSLD anode in a straight-to-perchlorate cell? I notice you seem to promote the idea of chloride->chlorate chlorate->perchlorate in a two stage process, which I can only assume is due to poor quality anodes. If you're interested, I've dug up some docs claiming surprisingly stable lead dioxide anodes on a tantalum substrate...Not quite the same, but I don't think it (the substrate) matters at the 5mm+ thicknesses they're dealing with...A couple of new plating baths, too - I haven't read everything here regarding chlorate cells and anodes yet, but it looks like everyone's doing the nitrate bath method.

Twospoons - Damn...I knew there was something I forgot to look at. Definitely gotta look into investment casting waxes. Do you have any ratios?


Definitely gonna stay away from the asphalt GALCIT style fuels, though. Not looking forward to working with them, and I'm guessing the thermal storage stability is not that great. That, and there's just something about tar...So versatile, but at the same time so crude and sticky.

Still nothing found on the wax fuel yet. It seems that I'm going to need to do a good bit of experimentation over the upcoming break, and I have shifted my priorities a little bit...I've tried building a chlorate cell in the past, but never had good anodes. This time may be different though - The master plan is to run a charcoal fired steam-powered tesla turbine powering a 5-10kW axial flux permanent magnet alternator, rectified and stepped down to 5-10v at a rediculously high amperage split across 10 or so five gallon bucket cells, each equipped with GSLD anodes and SS cathodes, hydrogen vented, running at 50-100 amps a piece...Ambitious, but it'll provide a shitload of cheap perchlorate if I can get it built. Possibly an income source as well, provided AP (better profit margin than KP) isn't some quasi-explosive in the government's eyes (look into the rocket fuel factory explosion...damn impressive blast, however tragic it was).

Bert - 31-10-2007 at 11:49

Do the math and report how many lb. of charcoal per lb. of perchlorate you will need. Then go look for a river to dam, unless you've got an AWFULLY large back yard.

Rosco Bodine - 31-10-2007 at 12:14

An erythritol / sorbitol melt , possibly with some "permanently plastic sulfur" and a bit of charcoal powder , as additives , maybe some MnO2 or a dichromate
added for a catalyst .....could make for an interesting melt cast fuel binder system , for nitrates or perchlorates .

Ketone N is another possible additive to a melt cast .

Here's the plastic sulfur thread
http://www.sciencemadness.org/talk/viewthread.php?tid=7732&a...

[Edited on 31-10-2007 by Rosco Bodine]