Ask MetaFilter questions tagged with materials

Are Miller Indices used for anything, or are they just a convenient notation?

selenized — Sat, 17 Oct 2009 09:52:11 -0800

I am taking an intro to materials science class, and in which we have learned about Miller indices, which are a way of denoting directions and planes in a unit cell. So far we have done nothing with this other than draw directions and planes. I was wondering, is this just a notational convention or is there some reason why they are the way they are, as in does it make some more advanced math easier or something?

Plastic temporary body jewelry needed soon

jet_silver — Fri, 11 Sep 2009 08:35:21 -0800

Temporary body jewelry for MRI not found because of advances in gardening equipment. Help. I'm having an MRI on Tuesday to confirm diagnosis of a labral tear in my shoulder. My nipple rings have to come out for it, I believe - they are 10 ga 316LVM CBBs - and I'm looking for plastic temporaries. In the past I'd have used .100" weed whacker cord for this but all the modern weed whacker cord is not cylindrical - it has sharp edges, by design, and that makes it unappealing. Four piercing places nearby (Silicon Valley / Santa Cruz CA) claim they have no plastic jewelry in this gauge.

My favorite place for raw materials stock, McMaster-Carr. The only plastic rod they list in .100" diameter is carbon fiber which doesn't sound too appealing either.

Nipple piercings, even old ones, have a reputation for closing up abruptly, so I am not sure that doing without will work. These piercings are old (1991) and if I am wrong about this then please correct me.

Please help with ideas.

Condensed Matter Forum?

Aanidaani — Mon, 17 Aug 2009 10:20:27 -0800

I'm looking for a forum that hosts discussion in the field of condensed matter physics and/or materials science. I'd like a site where scientists can go to ask and answer questions, similar to Ask.Metafilter, but a general forum would be good as well. Does anyone know of such a site?

The most light-absorbent material?

Rumpled — Thu, 30 Jul 2009 10:22:39 -0800

I need to stop a projection from showing up on a wall -- is there a particularly light-absorbent material that I could use? At gigs around where I live, it's become reasonably commonplace to replace light shows with a pre-prepared projection shone directly onto the band and the wall behind them. I had the thought that it'd be really neat if there was some material that I could hang up behind the band that the projections wouldn't show up on -- so that the crazy projections showed up only on the musicians and their instruments, and everything got a little more surreal.

An AskMe search turned up a similarish question of asuh's about what kind of curtain material blocks out the most light, with the general answer being velvet blackout drapes. It's a slightly different ask, but would they perhaps work best in this situation, too?

Needless to say, if anyone has a different solution to the problem ( ~ that of how to have particularise what a projection shows up on ~ ), I'd love to hear it. Barring science-fictiony unnattainables like this, how do you think I should go about this?

Deadstock in LA

gilgamix — Thu, 09 Jul 2009 11:04:16 -0800

Where can I buy large amounts of vintage/dead stock fabric in Los Angeles? I need to buy 750 yards of vintage/deadstock fabric. I need the fabric in assorted patterns. The fabric must be vintage, not simply discontinued. Help?

Do Prismacolor pencils ever go bad?

aquafortis — Sat, 11 Apr 2009 15:11:43 -0800

Do Prismacolor pencils ever go bad? I came across a stash of over 200 Prismacolor pencils that are about twenty years old. They seem fine so far, but are there any drawbacks I should expect from using them? Another mystery: I also have quite a few identical-looking pencils that say "Eaglecolor" instead of "Prismacolor". (e.g. "Berol Eaglecolor Sand 940; Berol Eaglecolor Copenhagen Blue 906.") Any info on what I've got would be appreciated. Thanks!

Cardboard in Pasadena

kepano — Sat, 07 Feb 2009 22:40:25 -0800

Where can I buy flat sheets of corrugated cardboard near Pasadena? I'm looking to buy large sheets of corrugated cardboard (24x48 inches or bigger). I need them soon! Hopefully in or near Pasadena, CA.

Suggestions?

Real-life tech-tree

Anything — Sun, 19 Oct 2008 02:54:12 -0800

"In order to feasibly produce, say, transparent adhesive tape, integrated circuits or sugar-free soft drinks, you need such-and-such materials and such-and-such equipment, which in turn depend on other things, all the way down to ores and fuel and such. So if you want to build your very own set of night vision goggles from scratch, here's everything you need access to in order to get started" Has anyone compiled, for the public to see, anything resembling a real-life 'tech-tree', akin to what's found in computer games such as Civilization? Such a database would help us see our everyday objects not just as things you can use, but as products of our society, and would greatly aid me in my secret plan for world domination.

Much of this kind of information is already compiled to such places as Wikipedia, and books such as David Gingery's series on how to build a complete metalworking shop from scrap, not to mention libraries full of industry and engineering textbooks, but nowhere have I seen it in a format that lays out technological and material dependencies explicitly for neat searching.

How do you make something that improves the acoustics of an auditorium?

n8stew — Sat, 09 Aug 2008 15:04:08 -0800

Can anyone offer me some suggestions for how to make a relatively inexpensive sound trap (i.e. like those echo reducers that large auditoriums have). Info about materials, shapes, etc. would be helpful. I'm a science teacher trying to make our school's auditorium more functional by reducing the echos which make it hard to understand most performances. I plan on writing a grant to cover most of the cost but I really need help figuring out what and how I would make these sound traps.

What's that material that swaps between images as you tilt it called?

paul_smatatoes — Sun, 01 Jun 2008 07:26:22 -0800

What's the proper name for that kind of image-switching material that switches between two pictures as you tilt it? I mostly associate it with novelty baseball cards, toys, children's books, and so forth. That plastic-y corrugated stuff? If I wanted to order a bunch of postcards printed with it, what am I looking for?

help me find a coffee mug printer who rocks!

clango — Mon, 14 Apr 2008 16:56:37 -0800

Anyone with personal experience printing coffee mugs? Ordered out for a few cases from a printer I would prefer not to libel, got a mushy print job in return. Can you recommend specific printers? (Especially if they can do even, opaque flat area coverage on dark mugs) Newest Q I see on here is from 2004, I'm guessing the landscape may be somewhat different.

secrets of the fine d-i-y

phoeniciansailor — Sun, 24 Feb 2008 23:11:16 -0800

what's the secret handshake that gets me access to the interesting/unusual materials that designers and contractors can get ahold of? i'm talking about things like double-walled stainless steel tubing. pvc "boards" that you can use outside in wet conditions. a specialty tree that i've started seeing around town, parkinsonia 'desert museum'. sheets of perforated corrugated steel for a fence we're building. cobblestones for the driveway. strips of "cor-ten" steel to edge our garden beds. and so on.

these are all materials that i've seen around town here in austin, but usually in commercial applications. unfortunately, it's hard to walk up to the girl behind the counter at crate & barrel and ask her where her contractor got the limestone for the building facade. :) and the materials are not at home depot or lowe's -- which may, at best, carry less specialized (and less interesting) versions. if i'm lucky, i can find something that might be what i need, online (hard to tell from a picture), but these places are never local, and shipping would be crazy.

is there simply an inpenetrable barrier between materials suppliers for designers and contractors and those for the general public? i want in, without having to hire an expensive go-between guy. possible?

Ironing plastic bags together...is this toxic?

tingting — Fri, 07 Dec 2007 12:44:54 -0800

You can make an interesting "fabric" (tutorial here) by ironing plastic bags together but I am pretty sure that doing this releases molecules of Something Bad into the air that I am then breathing. Am I right? Do I need a respirator?

Help me identify this fibrous roof sheathing

Bjkokenos — Mon, 17 Sep 2007 16:54:46 -0800

Help me identify this building material... What is this?
The picture was taken in a commercial building from the inside of the ceiling. This material is not only what you see from the interior but it is also the sheathing that the torch down roofing was installed on. It seems to be about 3" - 4" thick. It was also visible on the underside of the soffits. I have a client that is looking to get this repaired or replaced but I can't figure out what this material is. She has had a few contractors out that described it to her as a "composite" and they won't touch it.

Ping pong pros needed!

mphuie — Mon, 10 Sep 2007 11:17:40 -0800

Building a ping pong table to ITTF rules? Wood/paint selection help needed. I want to build a ping pong table. The construction isnt an issue but more of materials questions, mainly what type of wood and what type of paint to use.

I'd like to follow the ITTF exact rules:

'The playing surface shall yield a uniform bounce of about 23cm when a standard ball is dropped on to it from a height of 30cm.'

'The playing surface shall be uniformly dark colored and matt, but with a white side line, 2cm wide, along each 2.74m edge and a white end line, 2cm wide, along each 1.525m edge.'

So for the wood, (most guides say use MDF, how thick should I go?) I am also playing on carpet, would i need spikes that go through the carpet (like for speaker stands) for a better bounce?

The surface details arent very clear as for the type of paint used isnt very clear. Googling it seems to result in using chalkboard paint.

Does anyone have experience building ping pong tables?

What is the ideal material for a home-made, doggy-safe plush toy?

EL-O-ESS — Sun, 01 Jul 2007 22:24:31 -0800

What is the ideal material for a home-made, doggy-safe plush toy? (Posting for a friend...)

I tried to make a plush toy with squeakers inside of it for my dog. I made it out of polar fleece (what was most prevalent in the pet stores I went into) and it got completely destroyed within 2-3 days.

It's still much more economical to make these than to buy them, but I'd rather not have to do it so often. Is there a better fabric I could use? It needs to be able to feed through my sewing machine, which can handle things like denim, but ideally not be ripped to shreds in a matter of hours.

I thought about things like rip-stop nylon but this is too slippery for me to sew or for my dog to pick up easily. I have really only seen fleece, heavy-duty woven nylon (like for luggage straps) and the occasional organic cotton canvas toy. Surely there must be something better to use. Wool felt? Corduroy?

Any help would be appreciated.

Where can I buy scratch card paper?

Sevenupcan — Sun, 13 May 2007 13:34:31 -0800

Is there such thing as scratch card paper/transfer? And if so where might I be able to get it? A long time ago I saw these really cool scratch card stickers that let you make any message or image you wanted into a scratch card simply by applying the transfer/sticker onto the paper and cutting out the sticker.

I know there are companies that will print personalized scratch cards for you, but I unfortunately need too have the materially myself. So what I'm asking is it possible to by sheets of this stuff?

Graduate school prep

Aanidaani — Wed, 04 Apr 2007 12:14:57 -0800

Does anyone know any good resources for graduate school preparation, particularly in the physical sciences? I'm a sophomore and I want to get ready to start applying, but I need some help... I am currently in the second year of my study for a B.S. in Materials Science and Engineering. I am almost certain I would like to continue on to graduate school and enroll in a PhD program, but I'm not quite sure how to get started. I've looked at the sites for several programs and they all talk about the GRE, which I've started to prepare for, but otherwise I'm kind of at a loss.

For instance, how does one choose an advisor or a particular school? I am interested in magnetic and electronic materials, but I'm not sure exactly what I want to work on. Any web resources or books on the subject of applying to a graduate science program would be much appreciated. Thanks!

Advantages and disadvantages of other materials compared to steel ?

vincentm — Tue, 26 Sep 2006 08:13:18 -0800

What are the main advantages and disadvantages of materials like glass, concrete, wood, and plastics, compared to steel ? I have to build a small training course about the use of materials (in construction and manufacturing) and their advantages and disadvantages (resistance to heat, price, easyness of forming,etc.) in comparison to steel (carbon or stainless steel).

I found several documents but it is often too technical and detailled. If someone can give any nice web resources on this topic it would be nice.

Best source for weather-proof political campaign yard signs, including printing?

letitrain — Tue, 29 Aug 2006 11:47:37 -0800

Know a good source for weather-proof political campaign yard signs? I'm in California, the size is aprox. 24"x 18", with two colors, and the quantity is 2000-5000.

Stuff for science play and study

argybarg — Fri, 11 Aug 2006 13:55:55 -0800

I want to stock my 4th/5th grade classroom with materials that students can study, manipulate and experiment with on their own. I have no background in chemistry, geology or any other physical sciences. Yet I have a notion that I can fill the shelves of my classroom with substances, materials and tools that students can use to explore on their own -- making observations and discoveries and not harming themselves as they go.

Example: A bag of iron filings + a box of magnets. Or a circuit board + a high-powered magnifying glass. Or...my imagination falls short. Help?

Bonus points for materials that A) are readily available; B) do not combine with other liquids to make explosives. Extra bonus points if you actually know a child (your younger self included) who enjoyed mucking about in the manner described. Thanks.

Uses for old newspaper material?

pallen123 — Sat, 05 Aug 2006 09:39:37 -0800

Chemical profiles of typical newsprint and novel uses for recycled newspaper. What types of chemicals are in domestic, U.S. newspapers -- partic. harmful/toxic ones? Also, does anyone have any innovative suggestions for uses for old newspapers?

What durable yet flexible material should I be using for my longboard?

cheerleaders_to_your_funeral — Sat, 17 Jun 2006 09:14:16 -0800

I'm going to make the deck on my next longboard my self. What durable yet flexible material should I be using? The distance between the wheels of this board will be about 90cm (~35 inches), and the deck must be able to carry me on top of it, standing between the wheels, without it breaking. This is essential, I'll be riding fast on asphalt, so if it suddenly breaks in two I'll be in trouble.

Flex is also key. Feeling the board bend slightly as you ride through a turn is part of what makes longboarding great. Achieving this without compromising durabilty is the hard part.

The last time I did this I used 10 mm (~3/8 inch) of birch plywood. That deck had a shorter distance between the wheels and lasted for 2 and half season. It was good, but not perfect in terms of durability.

It seems reinforcing the wood with fiberglass would be a good idea, like having two 4 mm birch plates with fiberglass in between. But first of, I wouldn't know how to make them stick together, and second, I don't know what tools I'd need to cut it into shape.

How would you do it?

Help me get rid of large chunks of styrofoam.

young_simba — Mon, 19 Dec 2005 11:24:37 -0800

Hints on how to discard enormous pieces of styrofoam? Lots of big items come with very large blocks of styrofoam packing. If they're thick, they're very difficult to break into smaller pieces, especially without making a mess and expending a lot of physical effort. Also hard to get into even huge garbage bags. Is there a better way? Oh -- and I have no space to keep this stuff for potential future needs. Thanks.

Recommend a Hose!

Kafkaesque — Thu, 18 Nov 2004 17:58:28 -0800

Gardening question:

I bought what I thought was a pretty good garden hose and it's already kinking up like there's no tomorrow. What's the best material/best brand?