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Conduit Air Roaster
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| 6eight |
Posted on 08/17/2012 19:57
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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I have been away for a while so I have spent the day catching up on all the new roasters. Funny thing is I am only about 5% caught up. I have been using my bread machine/heat gun roaster for over a year now and want to upgrade. This just means it is time to tinker with odds and ends and see where the brain leads me. I stopped by a few Goodwill stores and picked up a Rotisserie that might be fun to play with, but I have wanted to build a fluid bed roaster since I first saw seedlings roaster built out of a leaf blower and a couple heat guns. I stopped at Homedepot and starting going up and down the isles looking for inspiration. I came acrossed a stainless steel sink drain and the wheels started turning. It was threaded at the bottom so I walked over to the electrical supply isle looking for fittings. At this point the wheels were spinning and I was looking for something to house a heating element. Then I came acrossed an electrical conduit box. The drain threaded perfectly onto the box. So this is where I want to start.
I have a couple questions for those that are much smarter than I about the conduit box.
1. It seems to be made out of aluminum so I am not sure if there is anything I need to worry about when it heats up? I wanted to use the conduit box due to the fact it was airtight (for the most part) and it would be easy to unscrew the front plate and replace a heating element if it were to stop working. It seems like a great chamber to mount a heating element in so this leads to my next question....
2. When it comes to elements I am a lost. Several of the posts start talking about the length of the nichrome wire and bending this and that. My brain goes to mush and I feel like my 4 year old in an algebra class. Any suggests on an element would be greatly appreciated. I am familiar with the heat gun elements since that is what I have been using, but I have tested the size of the element I have with the size of the chamber. I am guessing I will need two elements I one heck of a homemade one.
Thanks in advance for the help and I am looking forward to getting back to the site again!
6eight attached the following image:
I drive way to fast to worry about my cholesterol!
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| Dan |
Posted on 08/17/2012 20:13
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Founder - Member
Posts: 1798
Joined: 10/24/2005 17:09
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On a parts washer I made for work I used the same conduit fitting to house a Master Appliance heat blower heating element. Forced air comes in at the bottom and then angles out the top into the parts drum. |
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| 6eight |
Posted on 08/17/2012 20:26
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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On a parts washer I made for work I used the same conduit fitting to house a Master Appliance heat blower heating element. Forced air comes in at the bottom and then angles out the top into the parts drum.
Thanks Dan! The end of my shop vac fits right on the end of the Conduit box as I was testing it to see what size fitting I would need. Air comes through the box like a champ. How did you mount the element in the box?
I drive way to fast to worry about my cholesterol!
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| imaroaster |
Posted on 08/17/2012 21:00
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1/4 Pounder
Posts: 129
Joined: 06/19/2012 19:27
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6eight wrote:
[quote]On a parts washer I made for work I used the same conduit fitting to house a Master Appliance heat blower heating element. Forced air comes in at the bottom and then angles out the top into the parts drum.
What is the inside dimensions of the conduit fitting? I had to use a 2" pipe to house my master appliance element.
John |
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| Dan |
Posted on 08/18/2012 03:16
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Founder - Member
Posts: 1798
Joined: 10/24/2005 17:09
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I think mine was for 2" conduit. The box was about 3 x 3 x 8". The airflow in mine is very high, so the temperature is low, about 120°F, so I used a plastic fitting! |
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| oldgearhead |
Posted on 08/18/2012 05:23
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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This one (Master Appliance HAS-043K), along with it's 'protective' wrap fits nicely inside 1.5" sink drain:
oldgearhead attached the following image:
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| oldgearhead |
Posted on 08/18/2012 05:24
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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..like this:
oldgearhead attached the following image:
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| oldgearhead |
Posted on 08/18/2012 05:25
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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..plus tape and sealer:
oldgearhead attached the following image:
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| oldgearhead |
Posted on 08/18/2012 05:27
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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..and insulation:
oldgearhead attached the following image:
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| 6eight |
Posted on 08/18/2012 06:37
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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The conduit box I have is for a 1 1/2 inch pipe. The sink drain threads perfectly on to the top. I am going to play around with a couple elements that I have from old heat guns collecting in the garage.
Gearhead do you only use the one element in your drain and if so how many beans do you roast at a time. I am not looking for mass amounts of bouncing beans, but would like to get to 1lb if possible.
I drive way to fast to worry about my cholesterol!
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| oldgearhead |
Posted on 08/18/2012 07:02
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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I usually roast the amount that will fit in a one-quart Mason jar. With most beans it's 435 grams, but it varies a bit with the bean variety. I am connected to a 120 VAC/30A/10 gauge circuit, and the max current I've recorded is 21A, it usually runs 18-19A. My heater wattages are usually:
1) Drying = 1000W with 20% recycled RC air.
2) Ramp to first crack = 1300W with 40% recycled RC air.
3) Finish = 1150W with 20% recycled RC air.
The complete build is here:
http://www.homero...ad_id=2207
Oh, yes one 120V/1450W heat gun element, but I recycle..
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| 6eight |
Posted on 08/19/2012 07:06
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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Gear I love you roaster build. I have one of those old brewers at work that I may have to use for a housing. The original plan was to build a frame, but the coffee brewer has the perfect shape to it.
I have bee trying to find the glass tube, but haven't had any luck at the local craft stores. Looks like I will go online and fork out the shipping. What dia. is the tube on your roaster. I was thinking 4" dia. but wasn't sure.
All of the electirical "stuff" is making me re-think everything I originally wanted to do. I am a chef not an electrical engineer. If I am lucky my brother in law will help with some of the wiring.
I drive way to fast to worry about my cholesterol!
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| oldgearhead |
Posted on 08/19/2012 13:38
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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Corning 'Bake-A-Round' tubes are 3.5 inches I.D. The O.D. is less than 3.75 inches..
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| 6eight |
Posted on 08/27/2012 15:24
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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I have been playing around with a few configurations and will post some pictures later. I have a question about material that I am hoping someone here can answer. I have read in several posts to stay away from galvanized metal. I have several electrical fittings but I am not sure what those fittings are made from? I am using a conduit box (I think it is aluminum) and several pieces of 1.5 in pipe and nipples. So can someone give me a quick course in metal for dummies! Trying to avoid toxic materials since they don't go well with cream and sugar!!!
I drive way to fast to worry about my cholesterol!
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| oldgearhead |
Posted on 08/27/2012 16:28
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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Metal conduits:
Rigid Metal Conduit (RMC) is a thick threaded tubing, usually made of coated steel, stainless steel or aluminum.
Galvanized rigid conduit (GRC) is galvanized steel tubing, with a tubing wall that is thick enough to allow it to be threaded. Its common applications are in commercial and industrial construction. [1]
Intermediate Metal Conduit (IMC) is a steel tubing heavier than EMT but lighter than RMC. It may be threaded.
Electrical metallic tubing (EMT), sometimes called thin-wall, is commonly used instead of galvanized rigid conduit (GRC), as it is less costly and lighter than GRC. EMT itself may not be threaded, but can be used with threaded fittings that clamp to it. Lengths of conduit are connected to each other and to equipment with clamp-type fittings. Like GRC, EMT is more common in commercial and industrial buildings than in residential applications. EMT is generally made of coated steel, though it may be aluminum.
Aluminum conduit, similar to galvanized steel conduit, is a rigid conduit, generally used in commercial and industrial applications, where a higher resistance to corrosion is needed. Such locations would include food processing plants, where large amounts of water and cleaning chemicals would make galvanized conduit unsuitable. Aluminum cannot be directly embedded in concrete, since the metal reacts with the alkalis in cement. The conduit may be coated to prevent corrosion by incidental contact with concrete. The extra cost of aluminum is somewhat offset by the lower labor cost to install, since a length of aluminum conduit will have about one-third the weight of an equally-sized rigid steel conduit.[2]
In extreme corrosion environments where plastic coating of the tubing is insufficient, conduits may be made from stainless steel, bronze or brass.
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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| allenb |
Posted on 08/27/2012 18:11
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Super Admin
Fix It Man
Posts: 1472
Joined: 02/23/2010 19:51
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I used to believe that you'd have to get galvanized steel up to the melting point of zinc to create vapors but after further reading it appears it may create vapors at much lower temperatures.
Here's some info on max temperature ranges but not when vaporization occurs:
https://www.galva...peratures/
Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
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| 6eight |
Posted on 08/27/2012 19:25
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1/4 Pounder
Posts: 87
Joined: 10/27/2010 06:42
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OGH that is one heck of a lesson. With any of the non-galvanized varieties is there concern in high temp environments (i.e. coatings peeling, off gassing, etc.)?
I drive way to fast to worry about my cholesterol!
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| oldgearhead |
Posted on 08/28/2012 05:52
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Pounder Plus
Posts: 481
Joined: 02/10/2011 15:16
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I think aluminum would be the best. I use steel 'chrome' sink drain, but its not coated on the inside...
"Development of flavor, aroma, and body in the coffee bean is a chemical process which requires absorption of a definite number of heat units per pound of coffee-in the shortest possible time and the lowest possible temperature." - Sivetz
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