EQUIPMENT
Making your own motors is an economical means to rocket propulsion - over using Commercially Manufactured motors. This is the biggest untruth in rocketry today. Yes the price for propellant per event is greatly reduced however, surrounding investments to obtain self reliance is a whole new picture. The biggest investment for long term activity is in Equipment. We'll run down the list starting with the most obvious and go through some items never considered.
THE MIXER
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Obviously the top item that come to mind is the Mixer. Home Mixers such as a Kitchen-Aid can serve this purpose for small batches to load 29mm, 38mm, 54mm and even some 75mm motors. Once used for propellant they can NEVER be returned to their usual home use. The photo to te left shows a standard Kitchen-aid mixer. You want to be sure it is at least 375watts to handle the load as the mixture thickens and runs for a long period of time. More watts the better. Also make sure it has at least a 5qt capacity. Most home mixers are 4.5qt or less. This 5qt capacity will permit a 2000gram batch which will usually cover most small motor batches. You can find these home mixers everyday in department stores around the country going for between $275 to $400. Look around you can easily pick one up for between $150 to $250 on sale or used.
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To the right is a 10qt Hobart. This is ideal for the serious researcher as its higher capacity is nice for 3", 4" and 5" motors. You may still have to make multiple batches for large motors but it beats running two smaller mixers multiple times. A larger 20qt version is also available if you are looking to get into the business of motor making. The 10qt as show is more than sufficient for the serious researcher.
These are harder to find, usually in restaurant supply places or out of business pizza shops. The going price for a 10qt Hobart is around $1200 to $1500 reconditioned. Again shop around they can be found for $600 to $800 or cheaper. Wait for the right deal then move on it cause there are new pizza shops opening everyday!
Make sure the mixer has a bread blade like the one shown in the Kitchen Aid, not a hook. Also make sure the blade is rubber coated or non sparking metal. Its also advisable to purchase a second mixing bowl depending on how much propellant you'll be mixing.
A home mixer is portatble and can be stored and brought out for work in a small area. A commercial mixer will require a dedicated space in your work area. Keep in mind the commercial machines are much more heavy. E-Bay is a source for Commercial machines however keep in mind they are heavy and in some cases shipping can really raise the price.
VACUUM PUMP
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The Vacuum Pump is your second most important piece of equipment. These can be built from old refrigerator units or purchased. Its best to buy one if you're not mechanically inclined. The photo on the left shows a pump common to the type usually found on E-Bay. They can be found everyday for anywhere between $150 to $300. Again the key is to shop for a deal and move on it.
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To the right is a heavy duty Vacuum Pump. These are harder to find, at least at a reasonable price. This Alcatel 2008 lists at $950 rebuilt. It was actually purchased for $250, proving it wise to shop around. The most important thing is that it draws a good solid 29" of Mercury (how Vacuum Pumps are measured). Both pumps shown do this quite well and for our need either one will handle anything we can mix so be frugel and hope for a deal.
The best of pumps is no good without a vacuum gauge. These can be picked up at any supply house or McMaster Carr. Physical size doesn't matter as just about all of them will read the required vacuum needed.
VACUUM PLATE
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A must have item that you will have to fabricate is a Vacumm Plate to help draw trapped air from the propellant mixture. It is best designed to fit the mixing bowl used. It consists of a piece of Lexan Plastic with a center fitting, shut-off valve and circular rubber seal to hold the vacuum.
The photo to the right shows the Vacuum Plate on a Kitchen Aid 6qt mixing bowl. The clear Lexan allows monitoring of the evacuation process as the batch will swell tremendiously on first vacuum. The purpose of the valve is to break vacuum and not permit the mixture to touch the Lexan, it can make a mess. With practice this all becomes second nature.
You will also need an air line with quick connects to connect the Vacuum Plate to the Vacuum Pump. These are available at any hardware store. Use standard ¼"NPT fittings except for the fitting at the center of the Vacuum Plate. This is ¾"NPT. More details can be had in the FABRICATION section of this site. An informative page listing McMaster Carr items needed can be had there or by clicking HERE.
SCALE
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A good precision Scale is required. Do not buy a postage scale or kitchen scale. You need a Scale that will measure ounses or grams and even milligrams. It should be able to handle up to 5,000 grams or around 10 pounds. It must be able to tare, which is to compensate for weight already held. The smaller the batch of propellant is, the more accurate the measurements must be.
E-Bay is a good source for Scales, and again we state don't be cheap. A good Scale should run between $100 to $200. Good deals can always be found but make sure to check out what the actual retail price is. A $40 scale is not a deal when the retail price is $45. Harbor Freight is a good source but don't buy their bottom line stuff. The Scale is important so don't skimp, yet keep in mind its going to get abused. It goes without saying the more money you put out for a Scale the better care it will receive - maybe!
The above presents the basic needs for mixing Propellant however, there is more. Aside from all the "big" stuff there is a bunch of small stuff that all adds up. These are items you must have to make work easier and safer.
| ITEM | DESCRIPTION | |
| RUBBER GLOVES |
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Goes without saying actually. Never work with chemicals without wearing them. |
| SPATULAS |
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Rubber, not plastic. Used for scrapping down the mixing bowls during the mixing process. Several sizes come in handy. |
| SPOONS |
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Wooden or non-sparking metal, never plastic. Used when measuring ingredients. |
| ROLLING PIN |
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Basic kitchen rolling pin made of wood. Used for breaking lumps in material. Be cautious of materal friction or shock sensitivity |
| MEASURING BOWLS |
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Small paper or Cardboard picnic bowls. Ceramic acceptable but you should use throw away type. Never use the same bowl to measure different material. They can be reused if marked and stored properly. |
| ACETONE |
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Best for cleaning equipment and tools |
| PAPER TOWELS |
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Dah! |
