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Build Your Own Pellet Stove/ Pellet Smoker/ Gasifier

Bad Apple Automation, LLC
High Performance Pellet Burning


The goal of Bad Apple Automation, LLC is to produce products at a resonable price that allows our customers to experiment with pellet burning. Our products are not for everyone. You are required to have knowledge of, or know someone who has experience in electrical, fabrication, and engineering principles.

Our Products are for the true do it your selfer.

The goal of this document is to present our products to you, it is not a complete guide to building any pellet burning device. The purchaser must be knowledgable, and capable of designing and building the systems required for safe operation.

Pellet burning devices utilize several processes; a Fuel Feed System, a Burn Chamber, a Combustion Air/Exhuast Gas System, an Ash Removal System, and a Heat Exchanger. Additional systems are added for safety, such as a high limit switch to shut down the fuel feed system. The purchaser is responsible to ensure that proper safety devices are employed in the final design.

Bad Apple Automation, LLC makes products that simplify your design and build process.


A Fuel Feed System includes a Hopper, an Auger, and feed Control of the auger. The Fuel Feed System is accomplished utilizing Bad Apple Automation LLC'c CT-1000 Cycle Timer, AU-90 Auger Motor Assembly, and optional CH-90 Feed Chute.

The hopper is local storage at the burning device, it can be as simple as a 15 gallon barrel. These barrels often can be found surplus , or you can build your own to fit your exact needs. You size the hopper mainly for how often you want to re-load the local storage. However, having too much local storage can be a problem, as the added weight puts more strain on the feed auger, requiring more horsepower, ie. energy, and cost.

bad apple hopper Chose Your Size Choose the size of your Local Storage to meet your needs. Pellets have approximately 8,000 BTU's per pound. They come in 40 pound bags, which is approximately one cubic foot.

As an example, 3 bags of storage, at approximately 8,000BTU's/lbs, that's 960,000 BTU's (almost a million BTU's) of local storage before a refill is needed.

Now compare that to the amount of heat required, say 30,000 BTU's per hour, that implies 32 hours of burn time before a refill is needed.
bad apple hopper Chose Your Size When using a simple barrel, pail, etc, as a feed hooper, the pellets will create a natural cone of unusable material. You need to consider this when sizing your hopper. The cost of the pellets that form this natural cone are cheap compared to the labor and material to build a more complicated hopper. But the choice is yours.

The AU-90 Auger motor assembly can feed up to 115,000 BTU's/hour of wood pellets, or 14.3 pounds per hour. The use of the CT-1000 cycle timer allows you to throttle, or adjust the fuel input, as well as optimize the burn conditions.

Our products allow you to easily build the fuel feed system of your pellet burning device.

bad apple hopper example #1 Shown here is the CT-1000 Cycle timer installed (enclosure not included). Please note the CT-1000 is meant for indoor use only. If used in an outdoor application, such as a smoker, an additional enclosure is required and not supplied. It is the purchasers responsibility for proper installation based on your requirements.

Notice the use of the cord on the CT-1000 allows for easy connection.

By making the CT-1000 easily removeable, you can heat your house all winter, then use it on your Smoker all summer. Just a way to keep your cost down and allow you to experiment with wood pellet burning.

Bad Apple Automation, LLC does not build or supply parts for this hopper or stand. It is only shown here as an example of what could be built. It is a simple stand made of pipe and small angle, the hopper is just a barrel. The Mounting Plate for the CT1000 will be offered soon, please check back with us.
bad apple hopper mount 1 Mounting the AU90 feed Auger to the hopper is simple.

Decide where the AU90 should be located and mark the hopper

Using the hopper flange layout specified in the product page for the AU90, locate and drill the mounting holes.

Notice the AU90 is mounted off center , this is to provide clearance between the hopper and burning device. You want to keep your fuel cool, a heat shield may be required, and is discussed later.
bad apple hopper Chose Your Size Locate your electrical junction box used to connect your power cord to the AU90.
bad apple hopper Chose Your Size Mount the AU90 and make the electrical connections. You may want to add a switch to shut off the AU90, either here or somewhere else in your system.

There are times when it is nice to be able to cut the fuel supply, but leave the rest of the system functional, such as, when cleaning or shut down of the system.

You may need to add a protective shield for the motor fan to prevent injury.

Notice the plug cord connection to easily attach and detach from the CT-1000 Universal Auger Feed Cycle Timer.

Flip the hopper assembly over and place it on your stand.

bad apple hopper example #2 Here the CT-1000 Cycle Timer, the AU-90 Auger/Feed Assembly, and the CH-90-14 Feed Chute are shown togeather. All you need to do is build your own smoker or pellet burning device.

The CH-90 Feed Chute shown, would actually be inside your pellet burning device. This picture illistrates that the AU-90 and CH-90 bolt togeather to ease assembly.

Heat Shields

Heat shields are necessary in various areas of your design. A heat shield prevents heat from being transferred to unwanted areas, such as the fuel feed system, areas that are in contact with humans, or combustable materials.

A heat shield is created using one or more air spaces, usually a one inch air gap between each shield. The material must be non-combustable, usually a metal such as steel that can withstand the temperature of the application.

Heat has three forms, radiation, convection, and conductivity. Heat shields function using two of the three forms of heat, radiation and convection. The heat shield reflects the heat radiation, while the air gap allows for convection to remove some of the heat.

Using multiple heat shields reduces the heat significantly, versus a single heat shield. A single heat shield can have a high surface temperature as the metal of the heat shield itself absorbs heat. The surface temperature of a second, or third heat shield will be significantly lower.

During your design process it is worthwhile to purchase a temperature sensor to measure temperatures at various points of your design. Add additional heat shielding where necessary.

More Products Coming Soon!

Bad Apple Automation, LLC is developing additional products all the time, and continually adding information to this document. Please check back with us from time to time.

Copyright 2012-2013, Bad Apple Automation, LLC