I bought a soldering station a while back and was practicing on a kit and had the website on assembly up while I was soldering using 60/40 tin-lead solder. Should I worry about splatter on the surfaces causing contamination? Or from using my keyboard/mouse while I was soldering? I occasionally snack in there and was wondering if I was slowly poisoning myself.  Edit: is there any way to clean it the contamination from the room?  Edit 2: Possible duplicate doesn't quite answer my concern on surface contamination and transfer of contamination I feel. For example when I touched a door knob after soldering but before washing my hands, would I have transferred any amount of lead contamination to the door knob in which case I could be unknowingly ingesting lead by touching the door knob and eating/drinking in another room?  Edit 3: question was not properly answered I feel, does lead transfer to surfaces after my hand touched the solder because if so wouldn't door knobs and light switches in my house be contaminated
120956
I was reading about tin alloys for electronics soldering and found it it has about 40% of lead in composition. Lead, everyone knows, it's very dangerous to breathe due to being a heavy metal. Also, I found some recommendations using the combination of an exhauster and a respirator when working with soldering. Is there any international regularization of which respirator type should I use? If not, which type do you recommend? Beyond this, is there any additional safety equipment recommended?  For economics reasons and for better soldering resistance, I've already discarded Pb free solder reflow.
40266
I have a small cast iron pan which I am working with, trying to make sure I understand seasoning/cleaning before moving on to a larger one. I seasoned with flaxseed oil (4 light coats, hour in the oven), and have cooked a few things - I made some Ghee, fried some onions, stuff like that. After each I washed with hot water (no soap), heated until dry on the stove and coated with a thin layer of canola oil.  Now, when I take a dry paper towel and rub it on the pan, a black residue shows up on the paper towel. I can't feel anything with my fingers and I haven't noticed anything cooking with it. I'm fairly confident this occurred after the initial seasoning - although I'm not sure I did this exact test with the paper towel.  Is this a) normal, or b) what is wrong and c) how can I fix it?  There are quite a few questions (and good answers!) regarding cast iron cookware on this site but I haven't been able to find one that deals with this specific issue.
116300
Twice in the past week or so, I've wondered whether my cooking utensil was still clean enough to cook / serve with. Here were the situations:   Cooking ground sausage (no casing). While breaking the sausage up, raw sausage clearly got on the back of the spoon. Over the course of cooking the sausage and later adding veggies, all visible traces of the raw meat disappeared. I finished up cooking, used the spoon to stir in some penne, and then served.  Candying some bacon. Put some bacon in the oven with some brown sugar on it. Used a fork to flip the bacon half way through. Then used the same fork to take the cooked bacon out of the pan and on to a rack.    Is this safe? When do I need to worry about contamination on my cooking utensils? What is sufficient to make the utensil safe again?
117685
I'm the kind of chef who chops up whatever the local bazaar has that week, adds a random amount of seasonings until the color suits my fancy and then cooks it. Somehow. Most days I don't go hungry.  The other day, fresh garlic was really cheap so I bought a bunch. The housewares shop had some little jugs with corks, so I picked one up. Back at home I chopped up a few heads of garlic, stuffed it the jug, then filled the jug with olive oil. Bread for the next two days had had a great dipping sauce! However dipping bread in oil uses up a lot of oil and not very much garlic, so on the second evening when it was about half empty I topped off the jug with fresh oil. I corked it, wiped off the drips from around the top with a paper towel and left it on the table.  This is what I found in the morning. (click for larger)    I am certain when I corked it the level of oil was below the bottom of the cork because I tipped it to see how the garlic was getting an and remember the air moving around in the jug. I am also certain the top was clean having wiped it off, and of course there was no puddle. Even stranger, as I have left it there today it has continued to drip.  The only clew seems to be garlic mixture seems to be producing periodic bubbles that float up through the oil. This does not explain to me how the oil got out, but it does seem like it must be producing   I see three fields for questioning:   Casual kitchen tinkerer: How should I safely store my garlic and olive oil? Is there danger to storing this in something that seals better than a plastic cork? Is it safe to eat? Amateur chemist: Is there a chemical reaction going on between the garlic and the oil? Would it ever explode? Wannabe physicist: How did the oil get out? This seems like a gravity defying stunt. Note the current oil level is about ½" below the cork.   Somebody please tell me why my day's adventure at the bazaar made this much mess and how to make yummy things with garlic and olive oil safely!
40312
I just bought my first few pot and pans "Calaphon" stainless steel trip-ply  I used my new 10" skillet tonight, and cooked pork chops. I heated the pan first, added olive oil, let it heat, then added chops. After I was done, cleaned it immediately under water, and noticed white cloud looking areas on the bottom of the skillet. They won’t wash or rub off  Do I need to return these? I did buy them for the look as well.
114376
I cooked some bacon about a week ago and left the grease in the pan.  I've used it the last two nights with great success for cooking other meals.  How long is it safe to reuse?  I figure since I'm heating it up to a million degrees each time I use it it's probably pretty safe, but.... I'd rather not get food poisoning.
123623
Teflon toxicity and second degree burns aside, are there any health issues related to cooking with oil at or past its smoking point? Googling a bit I found one article that went so far as to say you should always "discard oil that's reached its smoke point, along with any food with which it had contact". Other searches showed pages suggesting cancer risks.  I've never given it a thought before and I often use peanut oil at smoking point to brown meat.
88983
How does the tester screwdriver work? If I put the tester screwdriver inside the "hot wire" of an electrical socket, it lits up if I press my finger against the metal cap on top of the screwdriver. This happens also if I stand on a surface of isolating material, such as wood. I read elsewhere that this happens due to stray capacitance formed by the "hot wire", the human body, and the ground. One has  $$ Z = R + \dfrac{1}{j \omega C}  $$  for the impedance, so if C  is high enough, the impedance should be close to r , the "effective resistance" of the formed circuit. Here I get lost; why r  is small enough to cause a current in the range of mA  even if I stand on an isolating surface?  So really what I am asking is how one may represent the system hot wire - screwdriver - human body - wooden floor - building - ground as an electrical circuit, and which parts of the physical system contribute to the resistance, capacitance (and inductance?) and in which proportion, even very approximately.
19611
Common sense says that you don't wave solder batteries, because the wave would short them for seconds. Yet in  I read       Primary lithium cells may be wave soldered as long as the cell temperature does not exceed +85°C. Cells may be placed in a holder or hand soldered after reflow (tabbed cells).     The first sentence seems to suggest that it's OK to wave solder batteries. Do I read this correctly, and doesn't the battery suffer from the shorting?
69043
My current setup is an ESD mat and ESD wristband both connected via alligator clips to unpainted screws that are screwed into a secondary PC power supply (not mounted in a PC case.) This power supply is then connected to an outlet. Would this be a good solution to be safe from static discharge and component safety from it?   I use regular screwdrivers and some of them are from a gunsmithing set, some from an electronics set. Would these screwdrivers cause damage since they are not specified ESD safe? Wouldn’t me touching the screw drivers ground them to the same level as me?  Is this a good set up to prevent ESD damage to components?  Are ESD safe screwdrivers and tools necessary in this case?
60680
When you look at the board, there is a weird part of the PCB right of the top left mounting hole. There is also another one above the top right mounting hole.    ****                            ↓ Here's one                                            **   This image is directly copied from .    What are these? Is this just created when this is manufactured (to grip to to move the board or to grip during solder mask creation), or does it serve a purpose (something to hook a multimeter to)?
60078
I've discovered spots on the image sensor of my DSLR camera that cannot be cleaned using a blower bulb, so I would like to know the risk of problems, such as further image deterioration or damage to the sensor or low-pass filter, associated with wet cleaning the image sensor.  Just how high (or low) is the risk?  Is this a difficult task to perform?  The products I expect to use are as follows:       In my research, I have also found the following products, for which there is a greater degree of trust because the manufacturer  when used properly:       Additionally, the reviews are generally positive, so is it worth it?  My biggest concern at this point is further staining or residue from the cleaning process.  How likely is this going to affect image quality, and would it be worse compared to the dust or other contaminants?
114810
I'm putting on my desktop computer on steel rack as usual. A while ago, when I touch the steel rack for seconds, practically I feel a tingling sensation, sort of electrical shock in my finders. After that I measured how voltage the steel rack has, the multi-tester meter indicated almost 50V by AC mode. Is this safe to touch or keep the PC on the position, or I should get away the PC somewhere electricity-safe? I'm not sure this site is suit for asking this kind of question, but I'm very worrying whether this is safe or not since this experience is my very first time. Thank you.
123583
If a home canned jar has botulinum in it can the jar be cleaned and saved? If so what is the correct way to clean the jar?
67261
Everybody has had the time where water gets all over their electronics, and the whole thing gets ruined, like cell phones.  At that low of a voltage (3-5&nbsp;volts), I don't understand why it is such a short-term harm (long term makes sense - corrosion, etc.)  If an LED was in parallel with water, maybe a bit more current would be drawn, but it doesn't seem to be enough at all to short out the system, and the LED would still shine.  So what is it that permanently damages some electronics and what is the cause?
82920
I have a PCB which has the perfect size for a project of mine, so I would like to use it if possible. However, the copper plating on the back side of PCB only surrounds the individual holes (that is, no holes are interconnected). See picture right here:    I find this strange. How can this be useful? I would definitely need some copper tracks with interconnected holes in there because some components need to be connected to each other. Am I supposed to make my own tracks somehow?  I saw some stuff online about people who would insert multiple wires in the same hole to make interconnections, but this seems undesirable. I'd rather avoid that if there is some way to make tracks.
111027
I am thinking about ordering up some parts for every day use. I am thinking about making one big purchase so as to minimize on shipping and other charges.   What are some of the components that any electronics hobbyist should have around ALL the time?  To put a little more scope: typically working with Arduino's, PICs and sensors. 5V - low current projects.   Looking for: component, value or range (if any), manufacturer (optional)   For example -  Resistors, 1K through 100K 5W