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Detroit Q. Spider posted:If I live to be a million years old I will never grasp why people think it's OK to Mickey Mouse something that presents a very real "burn the whole house down" possibility. Most homeowners have no idea. It's a matter of them going "ah it's too expensive to hire a pro... my friend's nephew knows a guy who is handy, and he'll do it under the table for $100. Then some chuclefuck makes a hash of things in the attic or crawlspace and the owner never sees it. But hey the water turns on and the lights work so it must be fine!
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Feb 24, 2013 19:48
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Konomex posted:if I could blast my dishes with steam It's called an "autoclave" and it's how you clean surgical instruments. However live steam is really goddamn dangerous.
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May 3, 2013 19:19
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Slanderer posted:If you just wanted to clean dishes, however, you could dispense with the pressurization, which would make it a good deal safer. Steam produces lots of condensation the instant it contacts cooler air, though. (You can see this in action when you boil water on the stove: all that billowing white stuff is condensation, not steam. Steam is transparent.) Without pressurization, it's difficult to heat the air up enough to have your steam stay steam as it moves from the heat source, all the way into contact with whatever you're trying to steam. Essentially what you're doing instead is hosing something down with really hot water. In which case, you might as well not dump in the extra energy it took to cross the liquid/gas phase change, and just wash your dishes with water 1 degree below boiling.
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May 3, 2013 20:07
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So, they're building a new span of the San Francisco-Oakland Bay Bridge. The need for a new span was identified waaaay back after the '96 Loma Prieta earthquake, in which a segment of road on the old span between Yerba Buena Island and Oakland collapsed onto the lower deck. It took over a decade for the two cities, CalTrans, and the feds to decide what to build and get the money and have arguments about the design and so on, but they finally got to work a couple years ago. Obviously this is a multi-billion dollar project. In March, with most of the major work done (the bridge is supposed to open Labor Day), a third of these 96 enormous galvanized bolts broke. Just straight up fuckin' snapped, and the bridge isn't even done, so that's some lovely longevity. Well it turns out that there is a nationally-accepted standard for how these bolts should be, and that standard is "not loving galvanized". But CalTrans or someone actually approved these bolts anyway. quote:ASTM International, the industry standards organization, has for decades strongly warned against galvanizing the grade of high-strength steel used to make the 288 anchor rods -- including those that broke -- plus an additional 2,018 fasteners used elsewhere on the suspension span's anchorage and tower, and to connect the cable and suspender ropes to the road deck. Only 96 of those pieces were manufactured in 2008. Fixing this problem is going to cost millions of dollars and possibly delay the opening, which is another multi-million-dollar bill. So yeah, thousands of lives at stake, decades to design a world-class major fuckin' bridge, obviously this is a very complex project and (ignoring the delays caused by politics in just getting going) up to now the project has actually been ahead of schedule and within budget. Which is basically unheard-of for projects of this scale. Still, someone (and nobody knows who yet) approved this and there's really no excuse.
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May 6, 2013 09:13
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I'd be more concerned with the wire swinging back and forth, allowing the ladder to sway and dip and whatever. I would not want to stand on that as it shifted under my feet.
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May 14, 2013 18:34
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kid sinister posted:That was on Reddit a few days ago. Here's the imgur post that picture is from. What's wrong is that the cheap rear end landlord only used 1/4" drywall for the bathroom ceiling, which apparently isn't strong enough to support a beehive full of honey that fell from the roof joists overhead. When it was full of honey midsummer, my beehive weighed at least 200 pounds. I don't think the grade of drywall is going to make much difference there, if the bees hang their comb on something other than joists.
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May 20, 2013 07:45
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Splizwarf posted:No harder, just more time-consuming Disagree. If he replaces it he has to bring it up to code. That could potentially mean re-wiring entire downstream circuits or more. Replacing a non grounded outlet with a GFCI outlet is always OK and does not cause you to have to do other work.
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Jun 10, 2013 04:04
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Splizwarf posted:But how will he disconnect the outlets to work on them? OK I'm not a contractor or a lawyer or whatever, so this is just my understanding. But basically there's kind of a rule where you can leave horrible old wiring in place as long as you don't touch it at all. But if you modify any of it you have to bring all of it up to code. Pulling out the old breaker box would presumably involve touching the ends of all of the wiring connected to it, so I assume that could mean replacing all of it. I could be wrong about what's involved in pulling the whole breaker box, of course. As for how to turn off the outlets, can't you just throw the main breaker switch? That's what I did when I replaced some of my outlets with GFCI. Of course, I don't have STA-BLOCK I don't think.
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Jun 10, 2013 07:20
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kid sinister posted:Do the old single-person electrician's trick. Plug in a radio to the offending outlet, turn it up loud enough to hear at the panel, and start flipping breakers until you hear it turn off. ...And then verify that there is no power on the line/outlet you're working on by using an appropriate tool. I have a "receptacle tester" which tests for current and also indicates if either blade/the ground is wrong/backwards/not grounded; and, a "voltage tester" which looks like this:  I can put that next to a line and it tells me if there's power in it. With all such tools I always verify it's working by testing a known-live line, and I always use it only as a backup/confirmation that power I have personally shut off is definitely shut off. I also always tape a sign to my breaker box which says "DO NOT TOUCH: WORKING ON LINES" even though nobody else should have any reason to go near my breaker box, just because I'm kind of paranoid about poo poo like that (my breaker box is on the outside of my house and accessible from the street).
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Jun 10, 2013 21:38
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DNova posted:
I live in a residential development built in the late 1950s in Concord, CA. The box is on the side of the house, but it's on the street side of the fence that fences off my back yard. It's a couple feet from the meter and directly below the drop where pole power enters the house. Seems like a pretty convenient place for it, really.
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Jun 10, 2013 22:31
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Jerry Cotton posted:It's locked, right? I mean it's not rare here to have them outside the house but not freely accessible to passers-by. No. There's a tab that I could use to lock the entire box, but frankly I think that'd be too dangerous. I don't want the main breaker switch to be inaccessible in an emergency. Guy Axlerod posted:I'd want to at least lock the breaker while I'm working on that circuit: That is a cool thing and I will try to find one. FCKGW posted:You all have me paranoid someone is going to flip my breakers in the middle of the night now If you have a security system, I'd make sure that it has some kind of battery-based thing that lets it report when your power is shut off. This should not by itself trigger an alarm, of course, but you don't want the evil criminals to be able to easily shut off your security just by throwing a switch. Otherwise I don't think it's a problem.
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Jun 11, 2013 16:41
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Is that how it is right now? That is not safe. Exposed wiring is pretty much never OK. Please don't touch it again without the circuit turned off and verified off using appropriate tools. Actually maybe just hire an electrician.
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Jun 11, 2013 21:38
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DNova posted:All of my residential wiring experience is US-based. I don't think anywhere in the US would use terminal blocks like that. But I also would have lost a bet that anyone would have their fuckin' breaker box OUTSIDE and apparently that is a common thing in some parts of the world... Alright well now you guys have me paranoid. So here is my deal, with exciting photos: My outdoor box is secured by a cactus!  (This Nopal cactus is a triple-threat. It discourages anyone from scaling my fence, it makes edible fruit, and you can also cut young lobes off and cook them.) Also note: encrusted remnants of many former cable and sattelite installations. The previous owners left me with no less than four defunct DISH network satellites on the roof, plus a former cable installation. Also running loving everywhere are phone lines, tacked-on exterior lighting, an old security system, an automated sprinkler system, and more; none of these things currently work. Yay. Here is the box in question, directly beneath the newfangled wireless smart-meter.  The smart-meter thing is pretty great. I can log on to PG&E and see my hourly usage, going back months. I can actually see exactly how much my A/C unit is costing me when it runs (I figured out it's a little under a dollar an hour, which is probably pretty poo poo but it's an old unit). This is what you see when you open the lid. I kept this a pretty large photo so you can read my amazing labels, which I made a couple days after I moved in. (Mystery Circuit is the 40 amp dedicated line for the A/C, I figured that out later.)  And if you remove the metal faceplate, here's the wiring.  It's old, there's some dead bugs and a bit of cobweb, but nothing looks horribly dangerous to my untrained eye. Is my house going to burn down? Leperflesh fucked around with this message at 01:50 on Jun 12, 2013 |
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Jun 12, 2013 01:43
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Built in 1958. With all the bedroom sockets on the same 15 amp line, I had to run a heavy extension cord from an unused grounded outlet in the kitchen back to one bedroom in order to have a grounded outlet for my computer stuff. That is probably not super-safe either, but it was supposed to be temporary until I could ground the outlets. Now my plan has changed to just installing GFCI. I'm still not super-certain that I won't overload that 15 amp circuit if I run everything in the back off of it, so I need to do some math and figure out how much load I'm actually putting on it at peak.
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Jun 12, 2013 01:53
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I have several grounded circuits in the house: at a minimum, I've tested & confirmed grounded circuits on the A/C, three in the kitchen (#s 6, 8, and 12), the #10 circuit in the garage (which may be separately grounded there since I found a grounding strap on the cold water pipe in the laundry area), and I think there's another grounded circuit (might be the second garage circuit, or it might be the front porch/doorbell, since the porch light has a ground wire that goes to the metal junction box the light's affixed to, but that might not actually be grounded past that point and I forgot to test when I replaced the porch light). The circuits that aren't grounded are the bathroom (which needs to be switched to GFCI), and the living room/bedrooms (which don't have to be per code, but I want at least one grounded or GFCI outlet in each bedroom if I can do it easily). Oh and the A/C I assume is 240v, everything else is 120v. I have a gas dryer so there's no electrical hookup for a dryer in the garage. Leperflesh fucked around with this message at 02:21 on Jun 12, 2013 |
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Jun 12, 2013 02:17
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hemorrhage posted:This is a common and accepted wiring method, known as an Edison circuit, or a multiwire branch circuit. Code now is to have a handle tie or double pole breaker for them, though. Can you explain what this means, in basic layperson terms? Like, should I only turn off certain breakers in pairs, or shoudl I go buy a tie for some of them? If so, which ones specifically? I want to be safe. 
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Jun 12, 2013 22:01
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kid sinister posted:A multiwire branch circuit is where 2 or more circuits on different phases share a neutral. It's mainly for safety reasons. Usually, those 2 circuits would be bundled into the same /3 cable on the red and black wires along with the white neutral. Well, that cable runs somewhere in the house. Suppose that someday you have to do work on the box where that /3 cable ends, so you shut off the circuit with the black wire at the panel, thinking you're safe. Then you go to untwist the red wire also in that box and you get shocked. The new code tries to fix that from ever happening. By tying those two circuits together, shutting one off forces you to shut the other off as well. This has been code for major appliances using multiple phases for decades. Depending on the manufacturer, either all the levers on that multiphase breaker are tied together, or that mulitphase breaker only has a single handle. Thank you for this explanation. However I do not appear to have a main breaker. I cannot turn off the street drop that enters the box. Is it dangerous to pull out breakers with the power from the street still coming in? Is this something where I need to call my utility to shut off the power to my house before I proceed? If this is too much of a derail I can move this to the electricity megathread.
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Jun 14, 2013 05:14
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babyeatingpsychopath posted:You're required by code to have a main breaker now, and have been for a very, very long time. Thanks. I will get around to posting over there when it looks like I have time and money to deal with my house's impending electrical disaster (apparently).
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Jun 20, 2013 03:18
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My father-in-law has a "stud finder" that is actually a little magnet on a swivel inside a little box. You can run it over the wall and when it finds a nail, the magnet points towards the nail, so you can slide it around and find the exact point over the nail. And then it has a little notch so you can mark that spot with a pencil. I bought a cheapo stud finder at home depot though, and I think it was all of $12 and it not only beeps when it finds a stud, it also has a different thing that detects live wiring. So it'll make a different rapid beep if you're about to drill into a wire. I find that the live wire thing is super-mega-sensitive, though, so if there's wiring within like five feet it'll beep. Probably a higher-quality stud finder would do a better job. But anyway my point is the low-tech thing was really cool, but if there's any chance you might drill into a live wire, maybe get one of the electronic ones and save yourself from electrocution. And a magnet is still nice so you can find out you're about to try to drill right where a nail is, because that always sucks when that happens.
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Jul 17, 2013 23:41
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Mine starts beeping and turns on a light when I hit one edge of the stud, and the light stays on across the stud and then turns off. I always mark both sides of the stud and then drill exactly in the center between my two marks.
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Jul 17, 2013 23:49
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I love those lamps hanging out right above the pool, instead of some sort of ventilation. Who needs to worry about mold if you're all going to get electrocuted first!
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Jul 25, 2013 19:28
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Motronic posted:They did labor intensive work that involved grading yards properly, using better building materials, and digging drainage and rock pits around houses. Things that cost a lot of money that new builders "solve" with a $60 sump pump. They also had populations vastly lower than ours today, so they had far better options about where to put homes. And, of course, their homes collapsed or burned down a lot, too. Let's not forget that the awesome old construction houses we have these days are the survivor-stock; the lucky homes that happened to be well-positioned, well-built, and well-maintained. For every one of those, there's probably a bunch that didn't make it. https://www.youtube.com/watch?v=nU2y6ztlMAQ
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Jul 25, 2013 22:02
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Motronic posted:That's justification, not an excuse for poor craftsmanship. Oh absolutely. I only meant to say that we should not have overly rose-tinted glasses when talking about the good-old-days of home construction. Especially structures from 100+ years and more ago. The safety of modern structures on average far outclasses those of the 19th century, owing in major part to huge advances in materials technology, far better building codes and inspection regimes, and widespread standardization of building techniques. There were houses built by highly-skilled craftsmen from high-quality materials to a labor-intensive standard that would be prohibitively expensive today, which will last for centuries and are amazing. But there were also a lot of shoddy deathtraps, houses built in freshly-drained swampland, and occasional city-spanning firestorms that burned hundreds down at a time due to entirely foreseeable and preventable (even at the time) conditions.
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Jul 25, 2013 22:23
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t_violet posted:I found these pics via a blog post. I've seen this kind of thing before, and it baffles me. It's like people don't understand that the alive part of the tree is the crust, which grows every year. You'd intuit this quickly if you even bothered to think about how a tree has rings and how those rings must form. So it's like, hey, every inch of the live part of the tree is going to expand every year, so what are you going to do, cut ever-larger holes in everything as they do so? Or just let them be restricted by your walls and floors and poo poo, while the tree puts (enormous) pressure on them? And then of course there's that other part where trees eventually die. Also, bugs.
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Jul 28, 2013 08:41
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Sagebrush posted:
Hah, I was wondering if someone would call me out on that. The outer parts of the bark are not alive, although the inner parts may be on younger stems. However, there are layers just below that that are the always-alive parts, including the cork cambrium and vascular cambrium, which sandwich the phelloderm and the secondary cambrium. The xylem and the phloem are the parts that transport sap up and down (respectively) the tree, and they are generated by the vascular cambrium, and then... Yeah, so basically its the crust.
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Jul 29, 2013 18:20
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It works because regulatory oversight in developing countries is generally poo poo. Corruption doesn't help.
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Oct 28, 2013 22:07
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So basically you were a butler for a mason. Which brings me directly to another thought: Are the masons all, like, Masons? As in the masonic order? If not, why the gently caress not!
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Nov 5, 2013 23:31
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There are regulatory solutions. Some properties come with easements or building restrictions that would have prevented that dude from putting up his 40' wall. The neighbors could all get together and petition their local government (town or, if unincorporated, county) to try and get the lot re-zoned or something. But, once the wall is up, it's probably a lot harder to do. I think it's pretty common (and in my opinion somewhat foolish) for people to purchase lots in rural areas recently zoned and subdivided for development, on the assumption that they'll be living with big views of nature on all sides. They throw up their lovely log cabin, and then experience a prolonged multi-year sense of dismay as all the other lots also get developed, and they find after a decade that they're now actually living in a suburb. If you really want to live with no neighbors, you either need a whole lot of acres, or you need acreage entirely surrounded by protected greenspace.
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Nov 21, 2013 23:54
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That is definitely not up to code if it's in California, but I don't know about other states. Here, it would have to be set on a raised platform and strapped to the wall, and also have a certain amount of space all around it. Also it looks like it's a gas-fired heater so it has to have proper ventilation above, but I can't see what's there. Water stains near the relief valve might be OK since it's fine to drain the water heater using that pipe.
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Dec 28, 2013 02:07
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Oh, yeah, sorry I didn't mean to imply that any of that code would apply to this heater, even if it was in California. On the other hand, the point of being up to code isn't entirely an exercise in legal compliance: most codes are there for reasons (of safety) and those reasons may be applicable even if the law isn't. Yeah I guess that's flexible electrical conduit? Huh. ...my heater doesn't have a pan under it, I don't think.
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Dec 28, 2013 02:42
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This is one of the hazards of large housing developments in general. Crews move through the development doing specialized jobs. So you'll have a crew doing grading, and then a crew laying sewers, then a crew doing foundations, then a crew putting up frames, then a crew putting in wiring, a crew doing exterior shells, a crew doing parts of roofs, and so on. And although there's usually no more than a half-dozen standard layouts, a lot of the houses have specific differences to them... especially if they're pre-sold and the buyers had optional upgrades. So potentially every house is a little different. And some crews are only going to be on-site for a few days, blitzing through everything blowing insulation into ceilings or putting up drywall or just spraying on a popcorn ceiling treatment, whatever. The potential for errors in that kind of situation is huge. The guys painting the walls don't know whether the guys doing the drywall hanging did their jobs right or not, and if they do find mistakes, there's probably a big incentive to just cover them up, because anything that delays one crew could cascade down the line and delay everyone else, which with a development with like 50+ houses in it could add up to millions of dollars of delays. There's a lot of pressure on each crew to get done to a tight schedule, so nobody really wants to hear the electrical crew putting in lighting telling them that hey, there's some shoddy framing on House Number 231 and really someone should tear down the drywall in the kitchen and dining room and fix it. You also don't have one specific person who is responsible for making sure each house is done exactly right at every step. Or if you do, that guy is in charge of so much that it's impossible to do it personally, it has to be delegated. It's the kind of situation that's ripe for mistakes, and since so many homebuilding mistakes become invisible once you put on the final paint, siding, and roof, well... that's why if you're me, you never even consider buying a cookie-cutter home built in a large development, especially since maybe 1980 or so when the process got far more "efficient" (read: cheap). Mind you, my home was built as part of a 1950s development, but it was a pretty small one, it would have taken longer to do, it's a smaller house with fewer features to go wrong, and it's been around long enough for any serious flaws to show themselves. And I got thorough inspections done. And even so, I'm sure it's not as high-quality a house as one that was built to spec as a one-off by a single contractor and their subcontractors. At least, potentially, since as we know, that situation has plenty of opportunities to go wrong as well... if the primary contractor is bad. It's also easy to discount modern tract-built housing because of the above, but we should also remember that building materials and products are way, way better today than they were even just 30 years ago. Modern plastic pipes, modern insulation products, modern framing techniques, modern wiring, modern appliances, modern infrastructure like sewer, water, gas, and electricity delivery... it's all more durable, safer, and in many cases just way nicer than before. There are legitimate attractions to preferring new construction over old. Leperflesh fucked around with this message at 23:46 on Jan 28, 2014 |
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Jan 28, 2014 23:44
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adorai posted:There are a lot of nice things about the way homes are built today over how they were built in the 70s and 80s, but I really have a hard time agreeing with the idea that any new construction house is going to be more durable than a reasonably well maintained home built 30-40 years ago. Siding and roofing would have been replaced with newer products over the years, bringing them up to the same quality that you would see today. Framing, sheeting, and drywall products are not significantly different, though the framing methods used today may use less material in different configurations (plywood I beams or 2x8s instead of 2x10s floor joists, as an example). Oh, I'm sure in some cases things are basically the same, and I'm not an expert on vintage building materials. But stuff like drywall that has a longer burn-through time, or drywall that has better noise insulation; framing techniques that are safer in an earthquake (I'm in California so earthquake safety is a big deal here); separation of the garage space from the house space with fireproof materials to slow or prevent spread of fire from the most common ignition source into the living area; to just basic poo poo like double-glazed windows, caulk that lasts longer, or even just bothering to put any insulation at all in places like floors and interior walls. (My 1958 house has no insulation at all between the crawlspace and the floor; it's a mild climate, but we still lose a lot of heat through the floor, and when I can afford it, crawling around down there installing a vapor barrier and insulation is on The List.) Durability of the overall structure is also affected by things like site preparation before building, and I'm convinced we're better at that than ever before. A lot of 50+ year old houses have areas where the foundation has settled over time, and that's just not going to happen as much for modern (say, 1990's+) houses where the site was compacted, drainage was better understood, geologists identified the flows of water, all that stuff was done to modern standards. I do think a lot of new developments have been allowed without adequate infrastructure planned (things like water supply in arid environments and sufficient transportation to get people to work). Suburban sprawl is a terrible blight not only because it's ugly and because it consumes prime farmland around cities, but also because the low density distribution of the population makes it more expensive and inefficient to deliver utilities and public transportation. A lot of big modern suburban developments are possible only because there's a big chunk of undeveloped land that gets bought and developed, and those big chunks are almost always former farmland on the outskirts of a metropolitan area. I'm really happy that I can walk from my house to the main commercial center of my town in about fifteen minutes, and my wife can walk to BART in about ten. I think it makes the plot of land my house is on more sustainable for the long term (say 100+ years) than some house twice as big on twice as much land that's out in the exurbs.
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Jan 29, 2014 02:13
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Sagebrush posted:So this means that unless you plug into the special uncontrolled outlet, all your computers and poo poo will have their power cut when you've been working late at your desk and no one's walked past the wall sensor in fifteen minutes? The outlets are labeled. I work in a corporate office sometimes and this is pretty normal. You'll have a color-coded outlet that's attached to the light sensor and switch, and another one right next to it that is always on. Basically the idea is, wherever you might plug something in, you have the option, so you can plug things like desk lamps into the one that's on the room motion sensor and they'll only be on if someone is in the room. You plug your PC into the always-on outlet. It can be annoying when the lights switch off because you were sitting too still, but that happens with the room flourescents too and everyone just deals with it. I expect the net savings my company gets from having all those sensors, just on electricity bills, runs into at least the hundreds of thousands of dollars a year, maybe millions.
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Jan 29, 2014 07:30
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DNova posted:gently caress this. That's actually what the general contractor is there for. If you distrust their ability to manage the job so much that you need to be there every day, you've not done a good enough job vetting and hiring your GC. He's your on-site professional house-building manager, and if you're constantly there micromanaging, you're undermining his ability to do his job. Visiting regularly and asking questions is reasonable. Hanging out at the job site every day is going to get everyone who works there hating you pretty quickly, and when your employees hate you, they will always do the absolute minimum that they can, and may even secretly sabotage you when they know they can get away with it.
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Jan 30, 2014 04:19
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Bad Munki posted:No time for that, the forum needs me! You're goddamn right you do. 
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Feb 4, 2014 20:39
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ntd posted:I suppose there is a good reason they make you sign a release Do they not, anymore? Mind did when it was installed 4 years ago. Fortunately my installer was competent: he ran it down a weather-protected wall, into the crawl space, and then up through the floor in the office, and he left me a big coil of extra cabling in the crawl space in case I want to move the access point to a different room of the house. kid sinister posted:gently caress, a guy in my fraternity house did that trying to get cable TV in his room. He drilled through the paneling and managed to drill into a 1/2" copper water pipe in the wall. Imagine the angle that you would need to hit a 1/2" water pipe at with a 1/2" drill bit and not deflect off of it. A friend of mine was installing shelves into a closet in his mobile home and he drilled right into a power line. I think the (cordless) drill absorbed a lot of the shock, so he was zapped but not enough to really hurt himself.
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Feb 4, 2014 22:33
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kastein posted:poo poo I completely forgot about fire rating. Thanks for the reality check, I'd hate for the tie rods to turn into linguini al dente in a fire. I've done a little bit of amateur blacksmithing, and the idea of supporting a wooden structure with steel cables or rods under tension scares me. Steel stretches with any heat, so as soon as they're exposed to significant heat, the rods or cables will get longer (or sag if they're not actually under tension). At 500 degrees Fahrenheit, tempered carbon steel starts to lose its temper - which means it becomes more malleable but less brittle. At 600, the temper is almost gone. You can still have very strong structures depending on what kind of alloy you're using - cast iron is very brittle but will hold its shape easily at this temperature, for example, which is why they make disk brake rotors out of it - but for any application that uses ordinary, tempered carbon steel, above 500F or so, the temper may be compromised (permanently, until it's re-headed to austinitic temperature, re-quenched, and then re-tempered). As an example of why the above is important; you sometimes see guys trying to free up seized bolts on a car by heating them with a torch. This could be OK if it's just mild steel, but high-strength bolts and high-strength steel members could be compromised by doing this, potentially a safety issue that could be invisible to the naked eye during inspection of the parts at a later date. At 500 degrees C (932 F), steel is just barely visibly glowing. You can bend it with hand pressure, shape it with heavy blows form a hammer, and at that point you should not be relying on it structurally unless you are a serious professional metallurgist/engineer kind of guy with an advanced degree in high-temperature structural application engineering type things. There's specialists who design things like combustion chambers and engine blocks and oil refineries and so forth who routinely deal with those kinds of applications, but you don't want to be trying to figure it out by yourself if you're not one of those specialists, and if the result of failure could involve someone's life or limb. Leperflesh fucked around with this message at 19:39 on Feb 17, 2014 |
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Feb 17, 2014 19:33
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Yeah, that's a generally good rule of thumb for basic carbon steels, and of course for mild steel (in terms of structural integrity - not in terms of changing the metal's properties after it's re-cooled). Mild steel is not tempered though, and annealing it does nothing. You can reheat rebar all you want, and when it cools (assuming it hasn't overly scaled from accelerated oxidization) it retains the same strength it had before you heated it up. And some steels are specifically designed for high-temp applications, retaining strength even while red hot. Example: gun barrels on high-speed gatling guns are designed to continue to perform while getting very hot indeed, and to have reasonable longevity even with hundreds of heating/cooling cycles. Your basic carbon steel has somewhere between .1 and maybe 4% carbon, alloyed with iron, with some insignificant trace elements in there. Stuff like 1080 spring steel, for example: it has .8% carbon, and you might see it used in leaf springs on a truck. Most of the car is still mild steel - body panels, for example - and that stuff you can freely weld on without worrying about altering structural strength. That stuff is commonly 1020, And then there's much more complicated alloys. There's probably hundreds of different bolt specifications in use, varying in alloyed metals... stainless steel has at least 10.5% chromium, for example, but there's tons of different stainless steel alloys. CrMo "chromoly" is chromium molybdenum steel, commonly used in cheap bicycle frames and such, with SAE numbers like 41xx. It's got varying amounts of carbon, some manganese, and you can case-harden it with a carburizing treatment. 4118 has only about .18% carbon, so I think it's un-temperable (assuming it's not carburized), whereas 4161 has .61% carbon and I would assume can be tempered. I do know though that you have to pre- and post-heat chromoly when welding it, though, so my best guess is, it's one of the steels you'd throw away if you had to torch it to get a bolt off of, unless you knew what you were doing (like, you're welding up bicycle frames, and you know how to properly pre- and post-heat it, and you know you're not using a carburized metal, etc.) That's just one example, but the point is, when guys are torching pieces of a car they sometimes know exactly what it's made of (an exhaust pipe hanger or a lug nut) and they sometimes have no idea. In the latter case, the smart thing is to assume anything you heated to 500F or higher is now trash. Leperflesh fucked around with this message at 20:43 on Feb 17, 2014 |
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Feb 17, 2014 20:40
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I think the most likely answer is that someone owned one or more aquariums, and decided to clean them out in the tub. I have several vivariums and by far the most convenient way to clean them is using the detatchable shower handle thing in the bathtub, because hosing them out in the yard means I can't use hot water and I always get bits of grass and stuff stuck to the wet tank while trying to get it rinsed off. So someone dumped an aquarium full of shells out into the tub and then instead of scooping up all the shells and sand and stuff they just rinsed it down the hole like a moron.
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Mar 15, 2014 00:30
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MrYenko posted:If they ever sell their house, shoot me a PM. Are you sure? You realize it will cost at least a billion dollars...
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Mar 15, 2014 22:33
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