How to make potassium chlorate - An another way

Making potassium perchlorate could be done by electrolysis of sodium chloride through the chlorate, and finally the double decomposition with potassium chloride, but here I will show you an another way for making potassium chlorate using household bleach.

All you will need is household bleach, potassium chloride and a big container.

First, pour at least a liter of household bleach in the container.
Then boil it for at least 15 minutes.
Finally, add potassium chloride until there is no more potassium chlorate precipitating out of the solution.
Filter to gather the potassium chlorate and let it dry.

Here is what's going on. Household bleach is a solution of sodium hypochlorite (NaClO) and heating leads to decomposition in sodium chlorate (NaClO3) and sodium chloride (NaCl).
Now adding potassium chloride (KCl) leads to a double decomposition between NaClO3 and KCl giving potassium chlorate (KClO3) that is a lot less insoluble than NaClO3, thus precipitating out of the solution.

The KClO3 can be used as is after drying or can be put into an electrolysis cell to give potassium perchlorate (KClO4). The solubility of KClO3 and KClO4 are very low so that there will be no separation possible until the end of the electrolysis.
But there is a way around this, you can make a saturated solution of KClO3 and let run the electrolysis until all the KClO4 is precipitated, filter and let dry all the KClO4.
Do again the procedure until you have made the desired amount of KClO4.

This procedure is not suitable for ammonium perchlorate because ammonium chlorate is VERY DANGEROUS AND UNSTABLE SO NEVER PUT ammonium chloride into the boiled bleach.

Curiosity touched down the Martian soil

What an amazing news : Curiosity, the rover the size of a 4x4 has finally touched down the martian soil at  5h31 GMT after 8 months traveling through space.
All went like scheduled and here is the first image sent by the rover :

To the bottom, we can distinguish the edge of the Gale crater where the rover landed this morning.

How to make a lead dioxide electrode for perchlorate synthesis

Here is a way I use to make my lead dioxide electrode

Lead dioxide forms on pure lead in dilute sulfuric acid. It use the same electrolysis procedure as to make ammonium perchlorate, however parameters change.

To make it, plug a lead electrode (a tube or a plate can do the job) to the + of the generator at about +1.5 V. Use any of those materials as cathode (- of the generator): copper, stainless steel or any other materials able to conduct electricity.
The electrodes are immersed in dilute (30%) and flowing sulfuric acid. To make it flow, you can use a fitted with a little blade like a mixer. The speed should be like a little swirl touching the electrodes. This avoid pitting the electrodes.

The electro deposition is carried out with a constant current at about 100 A/m2 for about 30 minutes.

Once you have made your electrode, you should manipulate carefully because it is a bit brittle.

Preparing the electrolyte for the process

Preparing fresh electrolyte

First, prepare a saturated solution of sodium chloride. Take about 40 grams for every 100 ml of solution and bring the solution to a boil. Then allow to cool to room temperature again. Some sodium chloride will crystallize as the solution cools. The solution is then filtered to obtain a clear saturated solution.

Optionally, 2 to 4 g/l of potassium dichromate, potassium chromate, sodium chromate or sodium dichromate may be added to improve efficiency. These compounds are suspected carcinogens, so if you choose to add any, know the hazards involved and act accordingly. If lead dioxide anodes are used, do not add potassium dichromate as it will only reduce efficiency. Instead, 2 to 4 g/l of sodium or potassium fluoride may be used. Although not carcinogenic, the fluorides are nasty compounds as well and should be handled properly.

Finally, the pH of the solution can be adjusted. A pH of around 6 is optimal, but anything between 5.5 and 6.5 is reasonable. The pH can be increased by addition of sodium hydroxide solution and it can be decreased by adding hydrochloric acid. Do not use too concentrated solutions for adjusting the pH. A concentration of 2% (w/v) for both solutions is convenient to work with.

Recycling old electrolyte

When electrolyte from a previous batch of perchlorate is available the following steps can be used to recycle the electrolyte.

If the electrolyte is not clear but has solid particles in it, filter to remove these and dissolve any impure chlorate from the purification and extraction steps.
After, re-saturate the solution with sodium chloride. The procedure mentioned above in step 1 of 'preparing a fresh electrolyte' may be used.
The chromate, dichromate or fluoride if added is still present so does not need to be replenished. The pH should be readjusted, like in step 3 for preparing a fresh solution above.

Or you can prepare a saturated solution of sodium chlorate  if you have access to it. Take about 60 grams of sodium chlorate for every 100 ml of solution and bring the solution to a boil. Then allow to cool to room temperature again. Sodium chlorate will crystallize as the solution cools. The solution is then filtered to obtain a clear saturated solution.

The electrode for making perchlorate

The range of suitable electrode materials is very limited. Especially the anode material is critical. The positive charge on the anode promotes oxidation and the evolving oxygen attacks many anode materials. Several anode materials have been considered over the years. Today's main options are listed below along with a short description.

Anode materials (plugged on the +)

Platinum: The obvious disadvantage of platinum is its high price. However, platinum anodes corrode only at a very slow rate and are suitable for perchlorate production. They therefore provide an almost ideal anode material. High efficiency can be reached with platinum and processing of the electrolyte is greatly simplified.

Lead dioxide: Lead dioxide provides an economical alternative to platinum. Lead dioxide anodes can be made at home. This takes some work and effort, but the anodes are cheap, fairly resistant to corrosion even at higher temperatures and are suitable for perchlorate production.

Cathode materials (plugged on the -)

Both stainless and mild steel find widespread use as cathode materials. Brass and copper may also be used. Each of these metals is protected to a certain extent by the negative charge present on the cathode as long as they are submerged and the current per surface area is high enough. Unsubmerged parts of the cathode corrode at a high rate however due to the action of evolving gasses and droplets of cell electrolyte

How to make ammonium perchlorate : electrolysis

As I told you earlier, ammonium perchlorate (AP) is not available in all countries.
Here is a way to make it.

First, AP is made by electrolysis of a solution of sodium chloride (table salt or NaCl).
Electrolysis is made by plunging 2 electrodes (an anode and a cathode) in an electrically conductive solution called electrolyte and plugging these electrodes to a power supply.

The electrolysis of NaCl results in the production of chlorine (Cl) and soda (NaOH). After a number of complex chemical and electrochemical reactions occurs as the chlorine dissolve in the solution.

This will yield sodium chlorate (NaClO3) if you have choose to use sodium chloride in your electrolyte, you can use potassium chloride (KCl) and you will have potassium chlorate (KClO3).
But KClO3 solubility is very low compared to NaClO3 so that it will precipitate out of the solution.
Not good for making perchlorate as the chlorate needs to be in solution in order to be electrolyzed in perchlorate.

NEVER USE AMMONIUM CHLORIDE (NH4Cl) in the electrolyte because the resulting salt ammonium chlorate is very instable though very dangerous.

Now that the sodium chlorate is made, let run the electrolysis. The chlorate will be electrolyzed to the corresponding perchlorate.

Once the electrolysis done, there is sodium perchlorate in the electrolyte. To obtain ammonium or potassium perchlorate, we will use what is called a double decomposition.
Introduce, either ammonium or potassium chloride in the solution and the corresponding salt will precipitate out as their solubility is very low compared to sodium perchlorate. To finish, extract the perchlorate and let it dry in the sun.

This post was the process of making the perchlorate, further post will cover the details like the electrode's materials (very important) and recycling the solution.

How to make nitrocellulose

Nitrocellulose, also known as gun-cotton, is like black powder but more powerful and smokeless.
It is a bit more delicate to make than the other propellant I wrote about but can still be made at home.

You will need concentrated sulfuric acid (preferably 95%), nitric acid (70%), cotton and sodium hydrogenocarbonate (baking soda).
Here is how to proceed :

Chill the acids below 0°C.
In a fume hood, mix equal parts nitric and sulfuric acid in a beaker.
Drop cotton balls into the acid. You can tamp them down using a glass stirring rod. Don't use metal.
Allow the nitration reaction to proceed for about 15 minutes (Schönbein's time was 2 minutes), then run cold tap water into the beaker to dilute the acid. Allow the water to run for a while.
Turn off the water and add a bit of sodium bicarbonate (baking soda) to the beaker. The sodium bicarbonate will bubble as it neutralizes the acid.
Using a glass rod or gloved finger, swirl around the cotton and add more sodium bicarbonate. You can rinse with more water. Continue adding sodium bicarbonate and washing the nitrated cotton until bubbling is no longer observed. Careful removal of the acid will greatly enhance the stability of the nitrocellulose.
Rinse the nitrated cellulose with tap water and allow it to dry in a cool location.

You can dissolve it in acetone to make nitrocellulose lacquer, extrude it (the shape of your engine for example) and let the acetone evaporate (preferably outside) and you will have nitrocellulose in the required shape.

But beware nitrocellulose is easily ignited, it will burst into flame if exposed to the heat of a burner or a match.

How to make Ammonpulver

Now another high power propellant the Ammonpulver.

The chemicals are Ammonium Nitrate and Charcoal, all of those in a very fine powder as always.

Charcoal is very easy to find and Ammonium Nitrate is a fertilizer but in some countries it will not be so easy to find it because of its nature.

However it can be made by gently pouring nitric acid on ammonia (common household chemicals), this reaction is exothermic so be careful to not auto-ignite the mixture.
I recommend using water ammonia and diluted nitric acid as water will absorbed the heat of the reaction.

You will have a solution of ammonium nitrate you can gently evaporate on a hot plate but do not heat over 150°C because AN thermal decomposition is explosive.

Now that you have all the chemicals, mix them at a proportion of 85% AN and 15% Charcoal.

Bind it if you want and you're ready to go.

However this propellant suffer some issues, "AN/C" is harder to ignite than APCP. My advice is that you use some Rocket Candy (described last week) for the ignition.

And it is also hygroscopic (it absorbs moisture from the air), so you will have to store it in a dry container.

How to make APCP

APCP is the propellant of the Space Shuttle's solid booster and it stands for Ammonium Perchlorate Composite Propellant.

It is very a good propellant with high performance : high specific impulse (300s average against 160s for rocket candy), high thrust and is not very expensive.

The chemicals needed are, of course, ammonium perchlorate (AP) but  it is not available in many countries. You can make it at home through electrolysis of a solution of sodium chloride but requires a special electrode to have a good yield. I'll describe the process in another post on how to make your own AP at home.

The second chemicals is aluminium powder, a very fine powder (under 250 mesh) more exactly.
You can buy it on the Internet, find it in a pottery shop as a pigment or make it by putting some aluminium sheets in a ball mill for several days.

Mix well (it's very important) the two components and add a resin like HTPB. It is in a liquid form you will have to cure it. The curing agent for it is usually a polyisocyanate compound like Isonate-143-L.

The resin and the curative are the most expensive products but a little bottle can last several use.

This is the most used formula for this propellant but you can still use another binder like dextrin or Parlon.

How to make Rocket Candy

Now, here's my favorite cheap and easy-to-make propellant : the Rocket Candy.

It's my favorite because it is very easy to make, it doesn't require a binder and it has pretty good performance.

The chemicals are just potassium nitrate (saltpeter) and sugar, the same sugar you use to make a cake, in a proportion of 65% KNO3/35% sugar.

The procedure is as follow :

• Put the chemicals in water in a pan.
• Heat and bring to a boil the water.
• Heat until there's no water remaining, you should have a white slurry, here's the propellant.
• Take this slurry and put it in your rocket engine.
• You can also put 3% weight of iron oxide (Fe2O3) or manganese dioxide (MnO2) as they acts as catalysts.
• BEWARE ! Do not heat for too long or the sugar will caramelize and it is very fire sensitive. Just a spark can ignite it.

The Rocket Candy can also be used as a smoke generator but you can't dyed it.
As always if you want to make it, the chemicals are available in the right side.

How to Make Zinc Sulfur Propellant or ZnS

This propellant is composed of, like it's name means, zinc and sulfur.

As always the chemicals needs to be finely powdered. All you have to do, in order to make it, is to mix them up and use whatever binder you want.

It's not a propellant I will recommend because it has a poor impulse and incredibly fast burn rate.

However this propellant leaves a spectacular large orange fireball and smoke trail behind the rocket.

How to make blackpowder

Black powder was invented by the Chinese 2 millenia ago and used in their own fireworks and rockets to celebrate their feasts. It's the oldest propellant of History and now you understand why I had to begin with.

Making black powder is very simple but you must follow some rules if you want it to work properly.

A black powder-powered rocket. Note that it makes
a lot of smoke.

You'll require 3 different chemicals : potassium nitrate (also known as saltpeter, you can find it easily in any garden store, it's a stump remover), charcoal and sulfur. You can find them in the link I provide to the right.

Now that you have all the chemicals, crush them SEPARATELY (never crush, grind, etc the chemicals together, some composition are very sensitive and can be ignited easily) to a fine powder. This is the most important rule, the chemicals have to be the finest possible if you want a usable powder.
If the grains are coarse, the black powder will not burn correctly. To do the job you can use a ball mill or a mortar and a pestle.

Once you have the finest powders possible, mix them well with the following proportion : 75% potassium nitrate (KNO3), 15% charcoal and 10% sulfur by weight.

You can now use it as it is (for pyrotechnic purpose for example) but it needs to be binded in order to stay in the rocket engine. I never tried it but I'm pretty sure that a binder like red gum can do the job.

I don't have the habit to use black powder in my engines because I use a more powerful and easier to shape alternative to black powder. I will describe it later in the week.

Have fun with your own homemade black powder.

Tools required for making propellant

Now that we know the major components of our rocket, it is time to make them.

First, we will make the propellant. Before beginning, gather all the required tools.

You will need : a ball mill or just a mortar and a pestle. The ball mill is less tiring but more costly. Those tools are required to crush the chemicals in fine powder.

It is very important that your powder is the finest possible. The reaction and burn rate will be faster and continuous.

You will also need some kind of resin to shape the propellant but you can also gently melt the different component in a pan. But you will need a hot plate instead  (less dangerous than gas stove because there is no open flame).There are resin like dextrin, Parlon that are great for making stars in pyrotechnics.
Some composition needs to be binded with a resin because they can't be melted (e.g too dangerous or decomposes before).

And, of course, you will need the chemicals. It's different for each propellant so they will be listed on each post.

Requirements for the rocket's structure

The structure must be able to sustain the weight of the engine, the propellant and the payload, and the temperature produced by the drag at very high speed.

It is primarily built of lightweight yet strong enough material like aluminium. It is not uncommon to see steel used for the structure, particularly in heavy rockets.

The structure also house all the guidance electronics, the payload and the propellant tanks if the propellant is liquid or gaseous.

The body is profiled to avoid drag that is encountered when traveling at super- and hypersonic speeds in the atmosphere.

More drag equals more energy to be put in, so increasing propellant mass for no other purpose that compensating the drag experienced by the rocket.

In rocket and missile design, these requirements are primordial to optimize the rocket but in our model rocket, we will not care about them.

For the structure and the body, a hollow PVC or carboard paper tube will do the trick.

And the drag is negligible because the propellant will be exhausted before the rockets reach a high speed, avoiding issues of drag.

The engine

The engine is the most important part of the rocket.

If you want maximum performance, it must be well-designed.

Each propellant acts differently in terms of pressure, temperature, etc. So the engine is designed according to the propellant that will be used.

Mechanically speaking, it must withstand the high temperature without melting and the high pressure resulting from the combustion without bursting.

To avoid melting the engine, it must be cooled. There are several ways to cool it : passively and actively.

Passive cooling is a manner that not use additional energy but is limited in efficiency and cooling power.

Two way exists : radiation cooling and ablative cooling.

A big rocket engine test firing

Radiation cooling is done by letting the engine glow white hot. The heat is dispersed by the light but it is effective for propellant that don't give temperature superior to the melting point of the engine's walls.

The second is done by putting a layer of resin (or something else like plastic for small engine) in between the engine's walls and the propellant so that the resin is vaporized by the combustion's heat. This technique is efficient, cheap and adapted to solid-fueled rockets but the ablative is consumed and must be replenished between each launch.

Actively cooling the rocket requires additional energy but is efficient and adapted to big rockets.

The general principle is to run the liquid propellant through (generally copper) tubings that are welded on the engine so that it can absorb the heat like a water-cooling. It only works on liquid and hybrid rockets because the propellants has to be a fluid.

 Ablative cooling is the cooling technique we will use in our little rocket engine. It's the most efficient and cheapest way to cool it.

Characteristics of the propellant

To choose a propellant, you will watch some characteristics.

I told you the propellant in the last post that your rocket is powered by a chemical reaction between two chemicals.

More this chemicals are energetic, more your rocket will be fast or able take off with a heavier weight.

When it is burns, the propellant produces gas. These gas are expanded by the temperature produced by the combustion and are expelled through the nozzle providing thrust according to Newton's third law.

Temperature depends on the energy stored by the chemicals and released when combusting. So more energy, more temperature and more temperature equal more thrust.

There is also the burn rate of the chemicals. A high burn rate is preferred because more gas are created providing a greater thrust.

But, a higher burn rate means also your propellant will be used faster. This could result in your rocket not reaching the height you expected.

Some propellant produce a lot of smoke,
some less or even not.

This impacts the specific impulse, also with the engine design, it is noted Isp and expressed in seconds.

Simply put, Isp is the time your rocket will fly with the propellant. It is the amount of thrust divided by the weight of your rocket. More thrust and light weight equals to high Isp.

However if you want to speed up the combustion, you can use a catalyst. Catalyst is another chemicals that is mainly used in the solid-fueled rocket sector.

You just have to add a little amount of it in your solid propellant and it will burn faster.

Catalyst are generally metal-oxides like iron oxide or manganese oxide mixed with the propellant in an amount of about 2 - 3% weight.

Each propellant I will propose to make will be described in terms of performance (thrust, Isp, etc) along with the chemicals needed, their proportions and how to shape them from powder to a more convenient form for your engine.

What is the propellant ?

The Space Shuttle,
one of the most famous rocket.

Like I promised, here is my second post.

I think it is important to explain all the parts you will be building before attempting anything.

So, a rocket is mainly 4 components : the engine, the propellant that comes inside, the body and the payload.

I will explain all the components, how to make them, one at a time.

So let's begin with the propellant.

What is it ? It's simply the fuel that propel (hence his name) your beautiful rocket up to sky.

The propellant consist mainly of 2 different chemicals that act together.

The first is the fuel, it is the chemicals that will burn (like wood or gasoline).

The second chemical is the oxidant, it's purpose is to burn the fuel (like oxygen).

You all know, thanks to your chemistry classes, that for something to burn, it requires oxygen.

But in space or in your engine there is not enough or simply no oxygen.

Simply put the oxidant is the chemical that bring the oxygen on it and allow the fuel to burn.

There is also a third component, the catalyst, but I will describe it in the next post because it is not in all propellants.

You also know that matter has 3 states : solid, liquid and gaseous.

So it's the same for the fuel and the oxidant : they can be either solid, liquid or gaseous.

Having said this, there is different kind of rocket, the solid-fueled, the liquid-fueled and the hybrid rocket.

First, the solid-fueled is like its name means, a rocket with the fuel and the oxidant being solid. They are the cheapest and the easiest to build.

That is the reason why I will concentrate in next coming post I will only give you recipes for solid propellant.

One major drawback is that it cannot be stopped.

After there is the liquid-fueled rocket. It is far more complicated and expensive that the two others.

It requires pumps, tubing and the fuel and oxidant, being liquids, are difficult to handle if you don't have the required tools. But can be stopped.

To finish, there is the hybrid rocket. It is between the solid and liquid-fueled rocket in term of complexity and cost.

Its fuel is solid and the oxidant is either liquid or gaseous.

In the following post, I will describe you what make a propellant a good one or a bad one in terms of characteristics.

The two little rocket next to the External Tank are the Shuttle's Boosters, they are solid-fueled.

The 3 thrusters behind the Space Shuttle are 3 liquid-fueled rocket. The fuel is liquid hydrogen and the oxidant is liquid oxygen.

The External Tank contains just the oxidant and the fuel for the 3 thrusters in separate parts but in the same container.

Welcome

Hi guys !!!

Welcome to my blog, The Rocket Blog.

Here I will guide you through the process of making your own little rocket that can climb towards the sky.

On it you will find links and information on the different parts, the chemicals used (even some pyrotechnics), news from the space industry and many more.

If you have any suggestion, feel free to let a comment or just contact me through my google account.

My first post will come in a matter of hours, so stay tuned.


I hope you will enjoy my site.

Jeremy, a rocket enthusiast.