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So apparently natural rubber latex can get weaker and turn sticky over time, i.e., it doesn't age well. Which latex substitutes age well (>30 year lifespan)? Polyurethanes? Butyl rubber? This is for a low stress application (just used for increasing the coefficient of friction of a surface)...

I want to buy some Kevlar, Technora, Vectran, Zylon, etc. cloth (not for resin impregnation) since it could make some really strong and lightweight clothing or kites. Why doesn't anyone make them? Is it too brittle? UV resistance? Cost? Low volume?

I'm looking for a material that melts lower than 90C but has less than 3% creep per year at 1Mpa and 45C. It should also have a tensile strength of at least 15Mpa at 40C Does anything like that exist? I know Polycaprolactone has a very low melting point, but what about creep resistance?

Hi guys, How do I estimate the drag of a well designed deep camber airfoil with a height to length ratio of 1/4.5 with 20% accuracy? Lift is not important, just need to minimize air resistance The aspect ratio would be 1/3, not sure if that matters much though I haven't been able to figure...

Also, where can I get nylon, polyester, and Vectran HT and HM monofilaments? (Or at least, extremely thin threads like, >0.05mm thick)

I need to get a spool of a single Kevlar 49 fiber (I can use Kevlar 29 if it's my last option) Does anyone know any suppliers? If I can't get a single Kevlar fiber on a thread, does anyone sell extremely thin threads on spools of the stuff? Also, does anyone know where to get carbon fiber in...

Ok that makes sense. Sorry I just got lost for a moment there

What if you got a drill bit and just drilled into a material (with a hole already drilled equivalent to the inner diameter of the spring, i.e. 0.25") with a properly lubricated drill bit with a strong cutting tip so you can have high chiploads? A 4" HSS drill bit should be able to make a 0.015"...

Wouldn't spur gears have a tiny variation in mechanical advantage as they go through different stages in where their teeth mesh? Basically the idea is that as the teeth mesh, they have to slide just a tiny amount, probably around 1% of the tooth pitch, but that also means that both gears change...

Ok, can you try a carbide saw blade like this though? http://www.amazon.com/D0748F-Diablo-Ferrous-Knockout-PermaShield/dp/B00008WQ3B/ref=sr_1_2?ie=UTF8&qid=1390604163&sr=8-2&keywords=metal+saw+blade

Can you test metal cutting wheels with teeth? Like saw blades? Supposedly those cut much faster, make an almost mirror finish, and last 20x longer than abrasive wheels. Can you also test cutting aluminum rods and carbon fiber too? I feel like silicon carbide might be a better material for...

What kind of chemicals and at what concentrations would protect natural rubber from oxygen and ozone like you suggested?

I'm more interested in what type of glue was used to bond the rubber

Not exactly because I need something that is stretchy. I think I'll try a coil spring or something of that sort.

I need something stretchy like a rubber band for holding things together, but it has to be very creep resistant because it needs to withstand a constant ~50% elongation for at least 3-5 years without significantly changing length/tension. I tried it with natural latex rubber but after only a few...

Hi, All of you here probably know how to electrochemically deposit an oxide film a few hundred nanometers thick that can use quantum effects to make bright colors. The thickness of the film is somewhat proportional to the voltage potential. However, is it possible to make a coating that is a...

What... how is there a patent on PWM for LED's? I have that in four of my flashlights, and two of them are made by some obscure chinese company and I doubt they pay patent fees for anything (though I could be wrong.) If there is a patent, it's probably expired or they just aren't enforcing it.

I'd like to be able to make a super efficient LCD backlight using laser diodes instead of LEDs. Would sure make our mobile devices have better battery life. I asked here because someone pointed me to this forum. Where should I be asking this question?

Are blue/green/red lasers more efficient than LEDs? I have read documents stating that VCSELs (a type of vertical chip laser) convert 66% of electrical energy to light - compared to about 33% for the most efficient white LEDs. The only problem is whenever I google actual VCSELs for sale, they're...

So couldn't Cree just take their white XM-L and just skip adding the phosphor to make a super-efficient and powerful blue LED? Apparently the appropriate term for phosphor efficiency is "quantum yield" which is basically the number of emitted photons divided by the number of photons absorbed...