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Post by Runewalker on Jul 11, 2007 9:01:36 GMT -5
While a newcomer may assume this community is monolithic in interests, orbiting around 1930s-60s electronic technologies as applied to guitar and amp guts ... I suspect that the community individuals can not contain their brilliance on only one area of interest.
That said, let's talk about BBQ lump charcoal technology....
I am converting an inexpensive smoker and then conducting mods to improve its performance. Substitute guitar or amp in that sentence and you can see it is just like what we do here.
One element in the ECB (el cheapo Brinkmann) smoker that needs improvement is the temperature assessment device (thermometer). I have a new one, but the sensor probe is to short. I want to lengthen it. but how to do so in a way that sustains its sensitivity along the extended length.
Because of this GN2 hobby I have sheets of copper. I thought about mere making a cylinder and attach ting it as a wrapped extension around the thermometer's probe. Copper is a good temp conductor.
But how to affix it and ensure functionality?
So here finally is the question for the engineers here:
If I make the cylinder and solder it, then fill the empty cylinder will that sustain the same temperature conductive performance as the original probe?
Smokers usually don't get over 500 degrees F. Will the solder we use for our GN2 projects survive that melting point. What are higher temp solder compounds. Is there a table of solder compounds melting temps?
No self respecting man in Texas is without a BBQ pit. And no, before any of you asks, or worse assumes ..... BBQ is not grilling, and grilling ain't BBQ.
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Post by RJB on Jul 11, 2007 11:11:19 GMT -5
Most electronic solders have a melting point around 215-230 C (410-440 F)
An alternate would be to find some coil spring material with an inside diameter just slightly smaller than the outside diameter of the probe. By counter-rotating the coil it can be expanded to slip over the probe, with decent thermal contact when released.
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Post by sumgai on Jul 11, 2007 18:58:30 GMT -5
Rune, I foresee problems.  Your current probe must be copper, at least on the exposed surface, or there will be a bi-metallic effect at the joint of your extension and the original piece. If the extension's material is not bonded to the probe, using the correct techniques, then the two metals will expand at different rates. The first problem is obvious, either the outer copper piece will expand too much, and fall off (or else lose heat conduction, regardless of the bonding agent), or else the inner material will attempt to expand more than the copper, and something will break. Maybe not expensively so, but it won't be a pretty picture, just the same. And then we get to the electrical properties of a bi-metal joint placed under expansion/contraction by external means (heat). That may or may not foul up your Temperature Assement Device Data Collection Unit. If everything is mechanical, then this fear goes away...... if there's any kind of wiring going on, then take note, please.  Does anyone in the BBQ industry make an extended length probe for just this scenario? If so, can you emulate their product? If not, can you find an offshore factory to get you into business with 5,000 units to start?  There's gotta be a demand for this thing, in a state a big as, well, Texas! ;D HTH sumgai |
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Post by Runewalker on Jul 12, 2007 7:12:23 GMT -5
Yes there are longer probed thermomenters, and yes some of you could have fun with that notion.
I just bought a shorter probe (thermometer) and am trying to make it work.
I sort of like the spring idea ---- most of those are steel and I am not so sure about the heat conductive properties compared to copper, and know of no copper, or even brass springs.
It needs to be longer because you want to position the sensor as near as the locus of the meat being BBQed.
The whole thrust of the mods is to tighten the incursion and expellation of air in the unit, thus making essentially an adjustable baffled 'chimmney' controlling both incoming fresh air and exhausted smoke. A tight "flue" which is what a pit is, and control of how it breaths gives the 'pit boss" relatively precise control over the temperature. And BBQ is a low and slow smoke-roaster, so controlling temp over an extended period is a key performance objective.
Plus, and here is the GN2 connection, if you are not tending the pit, you can build and play guitars while the brisket 'low & slows' for 9-12 hours.
The problem with an efficient pit, however, is that the typical hydration program of a pit boss is to tend the pit at the rate of 1 beer an hour. The pit is hot, Texas is hot, gotta keep the fluids flowing. If the pit is perking out there without tending, and the boss is inside under air conditioning, that compromises the hydration program.
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Post by UnklMickey on Jul 12, 2007 18:12:56 GMT -5
Yes there are longer probed thermomenters, and yes some you you could have fun with that notion. I just bought a shorter probe (thermometer) and am trying to make it work. I sort of like the spring idea ---- most of those are steel and I am not so sure about the heat conductive properties compared to copper, and know of no copper, or even brass springs. It needs to be longer because you want to position the sensor as near as the locus of the meat being BBQed. The whole thrust of the mods is to tighten the incursion and expellation of air in the unit, thus making essentially an adjustable baffled 'chimmney' controlling both incoming fresh air and exhausted smoke. A tight "flue" which is what a pit is, and control of how it breaths gives the 'pit boss" relatively precise control over the temperature. And BBQ is a low and slow smoke-roaster, so controlling temp over an extended period is a key performance objective. Plus, and here is the GN2 connection, if you are not tending the pit, you can build and play guitars while the brisket 'low & slows' for 9-12 hours. The problem with an efficient pit, however, is that the typical hydration program of a pit boss is to tend the pit at the rate of 1 beer an hour. The pit is hot, Texas is hot, gotta keep the fluids flowing. If the pit is perking out there without tending, and the boss is inside under air conditioning, that compromises the hydration program. Rune, I do understand your plight. It is an academic understanding rather than an knowledge of first hand experience. My probe has always been sufficiently long to meet the needs of reaching the hot spot. In the case of a temperature probe, just as any other probe, the portion of greatest sensitivity is at the tip. Adding an extension will allow this tip to experience the heat properly only in the case of a temperature probe. The extension in this case must be metal of some sort. Latex or other synthetics will neither conduct heat properly nor will they survive the heat. To connect the extension, it may be best to fashion it out of two strips of metal that form the "bread" of a sandwich around the probe's "meat". both the width and length of the metal should sufficiently greater than the probe. small screws into tapped holes, or through holes to nuts on the other side will placed on either side of the probe to clamp the bread onto the meat. There will be a gradient of temperature along the length of the extension, so the probe will not see the same temperature as the tip. You will likely be able to compensate for this by selecting a lower setting on your heat control than with a longer probe. Otherwise the system will be hotter than you might normally expect. It should cum as no surprise that using an extension would have such a result. It might be possible to wrap the probe in a material that will prevent heat loss along the length of the extension and the probe itself, leaving only the tip of the extension exposed. In the past that could have been an asbestos fabric. I don't know what a suitable replacement would be these days. If you are lucky, this won't be necessary. Cheers, Unk |
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Post by hammeroff on Jul 13, 2007 1:52:08 GMT -5
^^Wow
I'm rolling on the ground laughing Unklmickey!
Bravo.
+1
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Post by Runewalker on Jul 13, 2007 8:54:36 GMT -5
as noted: Yes there are longer probed thermometers, and yes some of you could have fun with that notion. Once the term probe came out I clearly understood the doors to the netherworld that would open. My probe has always been sufficiently long to meet the needs of reaching the hot spot... In this application, length is the dimension focused on. here, having and commending a long but sub-pencil diameter-dimensioned probe is appropriate; whereas in other applications those probes whose diameters are better reflected with a metaphor like, can-o-creamed-corn. Other notable applications require sensor placement that emphasizes girth opposed to depth. As you surmised, this BBQ application is, more for those who admire their pencil-diameter probes opposed to those lauded for their can-o-creamed-corn probe girth, and the subsequent sensor interactions. Using a metal extension married to the inadequately length-ed temperature probe is of course the challenge here. Other applications appreciate the rigid hardness of metal probes. William Burroughs for example touted the fondness one of his characters had for a certain "Steely Dan." However, this concept of a metal sandwich with torqued clamps ---- certainly may meet the engineering and heat conduction requirements, but conjures up certain cringing and wincing images, depending on the application. Unk, I laud you for admiring the length of your probe. However, I would not touch your probe with a 10' .... well .... probe. Salut RW |
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Post by sumgai on Jul 13, 2007 11:49:22 GMT -5
Say, just what's going on here?  Dare I say it........ Probing minds want to know! ;D |
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Post by UnklMickey on Jul 14, 2007 5:56:45 GMT -5
^ Chief, you should not feel that was risque. In fact compared to what preceded it, it might be considered rather soft. William Burroughs for example touted the fondness one of his characters had for a certain "Steely Dan." Rune, I must admit I knew nothing of Mary and her trusted companion in the night-stand, until I read the liner notes in one of Becker and Fagen's albums. I suspect you didn't even need to read the notes to know where they referenced the band name. On this same tangent, a quote from Wikipedia: "Naked Lunch is considered Burroughs' seminal work"Unk, I laud you for admiring the length of your probe. However, I would not touch your probe with a 10' .... well .... probe. Neither would I care to engage in any "sword-fighting" with you kind sir. I love you ....... but not in that way. Getting back on-topic (if that's even possible now), I hope you'll keep us a breast of the situation. I find discussions of BBQ to be riveting. I apologize if I've added fuel to the fire here. The most knowledgeable pit boss never use petroleum to start their coals. Chimney starters .......ForTheWin. . |
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Your current probe must be copper, at least on the exposed surface, or there will be a bi-metallic effect at the joint of your extension and the original piece. If the extension's material is not bonded to the probe, using the correct techniques, then the two metals will expand at different rates. The first problem is obvious, either the outer copper piece will expand too much, and fall off (or else lose heat conduction, regardless of the bonding agent), or else the inner material will attempt to expand more than the copper, and something will break. Maybe not expensively so, but it won't be a pretty picture, just the same.
There's gotta be a demand for this thing, in a state a big as, well, Texas! ;D
Dare I say it........