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Re: Fume extractor recommendation
Hi Radu,
You don't say what your scare was, but if your doctor deduced that the lead levels in your body are high, it likely didn't come soldering circuit boards. If you have lead in your blood, look first at hygene. Lead won't penetrate your skin to any significant degree from handling it, but it will from eating with unwashed hands that have been handling lead. Don't eat, drink, or put anything in your mouth while at your bench. Don't rub your eyes! Always scrub your hands after leaving your bench. I have watched a lot of technicians chewing on wire connectors, and wire insulation and using their mouths as a 3rd hand. Don't! Lead water pipes, and fresh lead soldered joints in water pipes are an excellent way of building up the lead in your body. Workers that need to watch out for lead fumes typically work around large circuit board wave soldering machines, or in a factory making or recycling lead batteries. Fume hoods used in soldering typically are just to reduce irritation from flux smoke. -Chuck Harris On Wed, 10 Apr 2024 17:30:08 -0700 "Radu Bogdan Dicher" <vondicher@...> wrote: Hi all, |
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Re: Fume extractor recommendation
John, I think I'd pay you that, add money for gas, house (+ dinner and breakfast) you for a couple of nights just for the company and conversation.? Radu.? On Wed, Apr 10, 2024 at 7:20?PM John Griessen via <john=[email protected]> wrote: On 4/10/24 19:48, Adam Kuzych wrote: |
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Re: Fume extractor recommendation
On 4/10/24 19:48, Adam Kuzych wrote:
you could add a 2-inch hole near your workspace, add in a dryer vent on the outside, and complete a solder fume extraction system with a $2K budget.Hey, for $2k, I might drive over from ABQ and make that hole in the wall...with all new ducting and fans... I lived in Santa Barbara for 6 yrs and miss the mild climate, foggy nights, and luxurious landscape plants of CA. |
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Re: Fume extractor recommendation
I appreciate that - and was just kind of determining it's an option, though pretty pricey new - but not used, please. The seller may have used it to make Cesium Christmas tree ornaments for all I know.? On Wed, Apr 10, 2024 at 6:51?PM Dave Casey <polara413@...> wrote:
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Re: Fume extractor recommendation
Metcal made (makes?) a HEPA solution that can be placed on/near/under the bench. I got a used one off the auction site for a fairly reasonable price by waiting for the right deal to come along. General model number is BVX-100. There's a few different configurations (with or without the hose, and possibly with or without the HEPA-rated second filter). Dave Casey On Wed, Apr 10, 2024 at 8:19?PM Radu Bogdan Dicher <vondicher@...> wrote:
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Re: Fume extractor recommendation
Ok, there's enough information on the problem now.
Apparently, soldering 20 feet away from a cooking area, on the same level of a dwelling, even with doors in the way, with a common airspace, single HVAC, and kids around is a no-go; don't do that. However, in a suburban garage, attached or unattached, soldering fume risks are much more manageable there. You're in California, the garage door can be kept open while soldering. Assuming the garage is owned rather than rented, and is a wood-frame building, you could add a 2-inch hole near your workspace, add in a dryer vent on the outside, and complete a solder fume extraction system with a $2K budget. I wouldn't do that though, it's unnecessary. Given the garage's isolation from the living space, proper ventilation, perhaps a shop fan in the garage with open door, it seems that would suffice. I use the equivalent of the Hakko 493 Smoke Absorber, and you could choose whichever model you want. Solder and solder fumes are dangerous for anyone, particularly young children in a home environment.? In a managed garage environment, I wouldn't expect solder and solder fumes to be terribly more toxic than a combination of fuels, oils, paints and thinners, lawn chemicals that may be stored there as well. It is lead, not cesium. Keeping a clean garage and home and managing the risks there should resolve this problem. |
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Re: Fume extractor recommendation
Thank you all. Plenty of paranoia here, but backed with some reality - I have young kids and the kitchen is a literal 20 feet? from the bench. Being in CA, I have zero alternative options to reconfigure this. I at least keep my bench in the garage, so there's no chance (or they're quasi-zero) I'd recirculate this through the home HVAC system. Paranoid enough to change my slippers between home and garage, so I'd not walk any dust in the house. The way I'm wired, one just can't possibly be careful enough. I also need a hair of stress - oh, I'm the best there is at this! - to lose sleep and that's just not something I?target.? What I'm concerned about is the typical stuff in regular solder, particularly in old equipment (which I tend to collect, repair, restore, calibrate, etc.). Obviously lead, and, as far as I know, stuff in the metrology realm - my relatively new interest of excitement - can also contain cadmium in low-emf positions.? Also, I have no way to easily exhaust to the outdoors. The garage has only two vents, one of which I've taken with an AC/heat pump unit needing to expel heat outside (of course). The high vent is open but has just about 1ppm efficiency, I'd say.? I think what I need is at least a two-stage thing: HEPA and active carbon. I'm not obsessing over odors or VOCs as much, it's the heavy metals I'm concerned about.? I'm close to a bunch of universities, I'll seek to inquire. Some sell affordable used lab equipment, but I know myself enough I'll not touch that stuff with a 25 foot pole.? Radu.? On Wed, Apr 10, 2024 at 6:02?PM Ed Breya via <edbreya=[email protected]> wrote: I think you need to be a little more specific. Do you want a full hood and exhaust outside, or trap the fumes in filter/chemical media? Or, do you just want to get it out of the work zone and diluted? |
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Re: Fume extractor recommendation
Yes. This is quite obscure.
I don't know what kind of bench soldering he's? doing, or how often, but there's a range of options out there. I have a very cheap fan and filter, it went on sale for $5, and tends to bring the fumes away from me sometimes. There's more extravagant setups for more extravagant soldering. Again, I don't know your application, or if OH&S requirements need to be followed, etc. As one example, assuming this is hobby bench soldering, and my cheap fan and cheap filter won't do, did you look through the Hakko website, to see if there's something you'd like there? Or is this an employer situation which is larger scope than these forums? |
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Re: Fume extractor recommendation
I think you need to be a little more specific. Do you want a full hood and exhaust outside, or trap the fumes in filter/chemical media? Or, do you just want to get it out of the work zone and diluted?
The most volatile toxic metal that could be encountered in soldering (or brazing) would be Cd, I think. Hg would not be in solders, but any spillage would be a problem. If such spillage is likely, keep a jar of flowers (dust) of sulfur on hand to help trap the vapors - just sprinkle it on generously. Cd should be fairly stable but easy to vaporize at elevated temperatures (like soldering), so you don't want that hanging around. Once things cool down, you'll have particles of the metals like Cd and the ubiquitous Pb (and its oxide) in the form of toxic dust - that's a good thing to trap out in filters. Any Hg around will eventually evaporate away and bind with O2 or S. The sulfide is fairly benign, unless you cook it out. Ed |
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Re: Fume extractor recommendation
See if you can reach the facilities department at a local university.? They should be able to point you in the direction of a supplier who can meet your needs.
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Peter On 4/10/2024 8:30 PM, Radu Bogdan Dicher wrote:
Hi all, |
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Re: Testing Scope Probes
What happens if you take a series of measurements, then disconnect the probes, flip the T 180 degrees, examine the result and evaluate both of them?
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Harvey On 4/10/2024 8:27 PM, jmr via groups.io wrote:
I'm not sure what you mean. One can't simply look at the BNC Tee and declare that the ~120ps length of each arm is so short at 500MHz that it is irrelevant. You have to analyse how the system will achieve steady state after lots of reflection trips back and forth through the Tee at 500MHz. The Tee isn't terminated correctly at its ends, and each end has a very different termination at 500MHz because the two probe types are so different. Hence the different reflections from each arm of the Tee and hence it will take a while to settle into steady state. At steady state at 500MHz, the RF voltages seen at each probe input will not be the same. There could easily be a 2dB or 3dB difference. This is enough to destroy the integrity of the test method in my opinion. |
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Re: Fume extractor recommendation
I have a few solutions, and it depends on how you balance paranoia, health, and work to do it.
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The classic chem lab solution is a fume hood. For a soldering station, you need a vent near the soldering point, a muffin fan ought to be sufficient (say 100 CFM or better), and exhaust it outside.? Chem lab solution. What's being done for a lot of commercial soldering stations is the same, but run the air through a carbon filter.? For your own use, go to a home box store, and buy filters made for air purifiers or for litter boxes.? Use them. If you're really really paranoid, use a shop vac with an outlet and exhaust it outside.? With that you don't need filters, you may need a welding torch because you're soldering in the midst of a hurricane. You could use a paint fumes mask, they're suprisingly comfortable.? I've worn them for hours at a time when doing floor coating and industrial scale wood treating. If you're curious, exhaust the air into a clump of weeds.? When they die, you know you have the right solution <grin>. Seriously, I use a a filter with a muffin fan that's designed for craft wood burning.? It seems to be enough. Harvey On 4/10/2024 8:30 PM, Radu Bogdan Dicher wrote:
Hi all, |
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Fume extractor recommendation
Hi all,
I've had a recent scare with potentially evil metals that can vaporize - you know who you are.... - and absolutely need a good, and hopefully affordable, solution for my bench soldering needs. And hopefully, not just something I'll put on there for peace of mind but have no idea if it really does anything. I really want this to work.? Are there any such things this community can recommend? I don't think I can go used on this kind of thing, not knowing what Martian "deadly on sight" materials the thing may have exhausted in its life. Nor I really feel I can trust the vanilla low balling specimens on AMZ. Being a health-related thing, I feel it kind of needs a trustworthy solution, but my budget for this is limited. Thank you for your input! Radu.? |
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Re: Testing Scope Probes
I'm not sure what you mean. One can't simply look at the BNC Tee and declare that the ~120ps length of each arm is so short at 500MHz that it is irrelevant. You have to analyse how the system will achieve steady state after lots of reflection trips back and forth through the Tee at 500MHz. The Tee isn't terminated correctly at its ends, and each end has a very different termination at 500MHz because the two probe types are so different. Hence the different reflections from each arm of the Tee and hence it will take a while to settle into steady state. At steady state at 500MHz, the RF voltages seen at each probe input will not be the same. There could easily be a 2dB or 3dB difference. This is enough to destroy the integrity of the test method in my opinion.
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8340B option removal
Has anyone had occasion to remove option 006 and restore the pulse modulation feature on an 8340B? The one I¡¯m looking at seems to have all the hardware in place (A21 pulse modulator board, A9 low band pulse modulator, A16 high band pulse modulator) just like the unit next to it but selecting pulse modulation gives me an ¡°option not installed¡± error message. I¡¯ve changed cal constant 60 Configuration to match the 8340B with pulse modulation but I still get the error message. I no longer have access to the 08340-10009 software package and I remember it having a ¡°Utility¡± menu that allowed you to change the option configuration. If it¡¯s not a simple cal constant change, is there something I¡¯m missing somewhere?
Thanks, Steve |
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Re: Testing Scope Probes
If the 3.5GHz 'known good probe' probe is a passive Zo probe, it might look like 500R in parallel with 1pF up at UHF. By contrast, a 10073C will typically look like about 60R in parallel with about 7pF across 400MHz to 500MHz. Quite a difference.?
This is going to upset the balance of Robert's BNC Tee based system. There's no way it will have any integrity up at 500MHz if I assume the distance between the probes is going to be about 45mm. This allows for the length of the Tee piece and some additional length for each BNC probe adaptor. This is a significant length at 500MHz. It should be obvious that the voltages arriving at the inputs of the two probes won't be the same at 500MHz, it isn't a valid test method for this reason.? |
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Re: Testing Scope Probes
One take-away from all this discussion is that it's very tricky to make good measurements at higher frequencies, especially with scope probes. It's hard enough even comparing probes attached to fairly well controlled signals and structures. Then think about hooking up to an actual circuit or DUT - everything will be different.
I think Chuck Harris said it best near the beginning of the thread, about not expecting good results using a 10X scope probe above 50 MHz (and the ground must be good too). Remember that traditional passive scope probes evolved from the tube days, for big, slow voltage signals. These are for general purposes, from DC to line to B+ and then lower circuit voltages. They're great at low frequencies up to mid-RF, and durable against say 400V LF just fine. You can try to measure almost anything with direct scope inputs or via probes, but you have to be aware of the limitations. You can readily get a qualitative picture of what's going on, which is usually sufficient to say if something seems to be working or not. For more precision at higher frequencies, a true 50 (or 75 or whatever) ohm transmission line conveyance is best, where everything can be better characterized (but still never perfect). Between there and a 1 meg//some pFs input, you can make decent compromises and scale factors work out. For higher frequencies, lower R is of course better, so I like the medium 100kR, 10kR, and 1kR ranges, for instance. These can be tricky to use inside active circuits though, where the DC biasing and such can be affected by the probe resistance, so AC-coupling is often needed too. If the frequencies of interest are high up enough, the coupling caps don't need to be very large. An option for getting both flat low-R RF, and DC-coupling is to have a DC-offsetting function included, like in power rail probes for instance. These need to have very low source R, so are not suitable for poking around in circuits, but the same principles can be applied to add utility to medium-R probing systems. Don't expect lower-R probes to be good for general purpose - go with the classic high-Z 100X/10X/1X ones then, which are comparatively indestructible. They really are different functions. So anyway, I think you can make decent comparisons between various probes, but only in relative terms, not absolute. When they're actually applied, keep the circuit/DUT characteristics and probe limitations in mind, while you do mental math and adaptation to get a better picture. Ed |
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Re: Testing Scope Probes
There seems to be lots of anecdotal evidence in the responses, and a few technical problems with the measurement setup of his original post. Is he following any one of many documented procedures here?
His 400MHz oscilloscope can't properly measure 390MHz with a 400MHz probe, as an example. He should be calculating his system bandwidth, and would require a probe bandwidth 2-3 times greater than his signal under measurement to be effective. I would expect there's other free documentation on this, and HP was particularly good on these older bench briefs, etc. Tektronix a bit less so. This could be concluded if the procedures were referenced. https://download.tek.com/document/60W_18324_0_0.pdf |
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