Pencil butane torch for Surface Mount desolder?
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From: Winston on 28 May 2010 10:49 On 5/28/2010 1:03 AM, N_Cook wrote: > N_Cook<diverse(a)tcp.co.uk> wrote in message > news:htnsgv$vpv$1(a)news.eternal-september.org... >> Winston<Winston(a)bigbrother.net> wrote in message >> news:htmhm6022th(a)news2.newsguy.com... >>> On 5/27/2010 7:42 AM, N_Cook wrote: (...) >>>> I like the solder paste indicator. >>> >>> It works 'better than nothing'. >>> Of course the virgin solder melts at a much lower temperature >>> than does the used solder. >>> >>> --Winston >> >> >> Another reason to investigate these , but 1/2 deg C resolution fine for > that >> purpose. For general fault hotspot monitoring 0.1 deg C resolution ones >> would be more useful but too expensive. I dunno. Plus / minus 10 C is all that is necessary. Your real indication is when you can lift the BGA off the board without undue drama. >> Another gizmo I must get around to >> trying. Using the pyrometer of a PIR unit , setting in an insulated tube >> shroud for pointing and then analogue fashion monitor the output in a >> relative way, absolute temp not required for that purpose. I understand that PIRs are A.C. devices, so one would have to be adept at 'blinking' the shroud at the target while capturing the resulting pulse from the PIR. As you say below, there is a much better solution. > In this situation would thore remote IR thermometers pick up the temp of the > board or the much higher temp of the hot air above it , but in line of > "sight" of the sensor? That is a good experiment to do. I *guess* that the infrared emissivity of nitrogen *at that temperature* is low enough that the infrared from the PCB would swamp it out. I do not know for sure. Product Idea! An infrared sensor mounted to your headband magnifier. Lensed LCD chart presented as a heads-up display in your magnifier continuously scrolls to show temperature at the center of your crosshairs. --Winston
From: N_Cook on 28 May 2010 12:03 Winston <Winston(a)bigbrother.net> wrote in message news:htol4m030c9(a)news4.newsguy.com... > On 5/28/2010 1:03 AM, N_Cook wrote: > > N_Cook<diverse(a)tcp.co.uk> wrote in message > > news:htnsgv$vpv$1(a)news.eternal-september.org... > >> Winston<Winston(a)bigbrother.net> wrote in message > >> news:htmhm6022th(a)news2.newsguy.com... > >>> On 5/27/2010 7:42 AM, N_Cook wrote: > > (...) > > >>>> I like the solder paste indicator. > >>> > >>> It works 'better than nothing'. > >>> Of course the virgin solder melts at a much lower temperature > >>> than does the used solder. > >>> > >>> --Winston > >> > >> > >> Another reason to investigate these , but 1/2 deg C resolution fine for > > that > >> purpose. For general fault hotspot monitoring 0.1 deg C resolution ones > >> would be more useful but too expensive. > > I dunno. Plus / minus 10 C is all that is necessary. > Your real indication is when you can lift the BGA off the board > without undue drama. > > >> Another gizmo I must get around to > >> trying. Using the pyrometer of a PIR unit , setting in an insulated tube > >> shroud for pointing and then analogue fashion monitor the output in a > >> relative way, absolute temp not required for that purpose. > > I understand that PIRs are A.C. devices, so one would have to be adept > at 'blinking' the shroud at the target while capturing the resulting > pulse from the PIR. As you say below, there is a much better solution. > > > In this situation would thore remote IR thermometers pick up the temp of the > > board or the much higher temp of the hot air above it , but in line of > > "sight" of the sensor? > > That is a good experiment to do. > > I *guess* that the infrared emissivity of nitrogen *at that temperature* > is low enough that the infrared from the PCB would swamp it out. > I do not know for sure. > > Product Idea! An infrared sensor mounted to your headband magnifier. > > Lensed LCD chart presented as a heads-up display in your magnifier > continuously scrolls to show temperature at the center of your crosshairs. > > --Winston The "ac" action is from the effect of the facetted mirrors in the PIR, producing signal change when a moving warm object moves across the boundaries of facet projected areas , a bit like fly's multi-lens eye structured as a movement sensor
From: Winston on 28 May 2010 12:44 On 5/28/2010 9:03 AM, N_Cook wrote: (...) > The "ac" action is from the effect of the facetted mirrors in the PIR, > producing signal change when a moving warm object moves across the > boundaries of facet projected areas , a bit like fly's multi-lens eye > structured as a movement sensor The way I misunderstand it is that the raw output of the sensor itself is A.C. With or without the faceted lens, a hot object presented to the sensor itself will result in a pulse, not a D.C. offset as one expects of a Si photocell, for example. I'm here to learn however, so I am open to new information. :) --Winston
From: Grant on 28 May 2010 22:48 On Fri, 28 May 2010 07:49:01 -0700, Winston <Winston(a)bigbrother.net> wrote: >On 5/28/2010 1:03 AM, N_Cook wrote: >> N_Cook<diverse(a)tcp.co.uk> wrote in message >> news:htnsgv$vpv$1(a)news.eternal-september.org... >>> Winston<Winston(a)bigbrother.net> wrote in message >>> news:htmhm6022th(a)news2.newsguy.com... >>>> On 5/27/2010 7:42 AM, N_Cook wrote: > >(...) > >>>>> I like the solder paste indicator. >>>> >>>> It works 'better than nothing'. >>>> Of course the virgin solder melts at a much lower temperature >>>> than does the used solder. >>>> >>>> --Winston >>> >>> >>> Another reason to investigate these , but 1/2 deg C resolution fine for >> that >>> purpose. For general fault hotspot monitoring 0.1 deg C resolution ones >>> would be more useful but too expensive. > >I dunno. Plus / minus 10 C is all that is necessary. >Your real indication is when you can lift the BGA off the board >without undue drama. I tap the board to encourage components to 'unstick' from the molten solder. > >>> Another gizmo I must get around to >>> trying. Using the pyrometer of a PIR unit , setting in an insulated tube >>> shroud for pointing and then analogue fashion monitor the output in a >>> relative way, absolute temp not required for that purpose. > >I understand that PIRs are A.C. devices, so one would have to be adept >at 'blinking' the shroud at the target while capturing the resulting >pulse from the PIR. As you say below, there is a much better solution. Yeah, PIR detector is hopeless at absolute temperature. What it does instead is rely on the warm body moving in and out of the lensed zones to create an AC IR signal. That's why they have that fresnel lens thing on them to define the IR zones. > >> In this situation would thore remote IR thermometers pick up the temp of the >> board or the much higher temp of the hot air above it , but in line of >> "sight" of the sensor? > >That is a good experiment to do. > >I *guess* that the infrared emissivity of nitrogen *at that temperature* >is low enough that the infrared from the PCB would swamp it out. >I do not know for sure. > >Product Idea! An infrared sensor mounted to your headband magnifier. > >Lensed LCD chart presented as a heads-up display in your magnifier >continuously scrolls to show temperature at the center of your crosshairs. Hmm, seen the price of a point-at-target IR thermometer? Add a couple more times that for the headsup display? Not cheap :( Grant. -- http://bugs.id.au/
From: Michael A. Terrell on 29 May 2010 00:24 Grant wrote: > > On Fri, 28 May 2010 07:49:01 -0700, Winston <Winston(a)bigbrother.net> wrote: > > >On 5/28/2010 1:03 AM, N_Cook wrote: > >> N_Cook<diverse(a)tcp.co.uk> wrote in message > >> news:htnsgv$vpv$1(a)news.eternal-september.org... > >>> Winston<Winston(a)bigbrother.net> wrote in message > >>> news:htmhm6022th(a)news2.newsguy.com... > >>>> On 5/27/2010 7:42 AM, N_Cook wrote: > > > >(...) > > > >>>>> I like the solder paste indicator. > >>>> > >>>> It works 'better than nothing'. > >>>> Of course the virgin solder melts at a much lower temperature > >>>> than does the used solder. > >>>> > >>>> --Winston > >>> > >>> > >>> Another reason to investigate these , but 1/2 deg C resolution fine for > >> that > >>> purpose. For general fault hotspot monitoring 0.1 deg C resolution ones > >>> would be more useful but too expensive. > > > >I dunno. Plus / minus 10 C is all that is necessary. > >Your real indication is when you can lift the BGA off the board > >without undue drama. > > I tap the board to encourage components to 'unstick' from the molten > solder. > > > >>> Another gizmo I must get around to > >>> trying. Using the pyrometer of a PIR unit , setting in an insulated tube > >>> shroud for pointing and then analogue fashion monitor the output in a > >>> relative way, absolute temp not required for that purpose. > > > >I understand that PIRs are A.C. devices, so one would have to be adept > >at 'blinking' the shroud at the target while capturing the resulting > >pulse from the PIR. As you say below, there is a much better solution. > > Yeah, PIR detector is hopeless at absolute temperature. What it does > instead is rely on the warm body moving in and out of the lensed zones > to create an AC IR signal. That's why they have that fresnel lens thing > on them to define the IR zones. > > > >> In this situation would thore remote IR thermometers pick up the temp of the > >> board or the much higher temp of the hot air above it , but in line of > >> "sight" of the sensor? > > > >That is a good experiment to do. > > > >I *guess* that the infrared emissivity of nitrogen *at that temperature* > >is low enough that the infrared from the PCB would swamp it out. > >I do not know for sure. > > > >Product Idea! An infrared sensor mounted to your headband magnifier. > > > >Lensed LCD chart presented as a heads-up display in your magnifier > >continuously scrolls to show temperature at the center of your crosshairs. > > Hmm, seen the price of a point-at-target IR thermometer? Add a couple > more times that for the headsup display? Not cheap :( $10 on sale at Harbor Freight. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
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