Fabric used as sheathing.

[Lord Nerdlinger]

Originally Posted by M. Krass

So, as we've been dealing with lowering our robot's weight considerably, we're investigating alternative methods of sheating our robots and its internal components from damage.

One method we're pursuing is the use of fabric rather than the traditional sorts of lexan covers many robots have. So, I've been wondering what sort of fabric teams used last season on their wings -- as seen on robots from teams like 60, 118, and 343.

We need something that's light, strong, readily available and, with luck, puncture and tear resistant. Does anyone have any suggestions?

Thanks.

I hear spider silk is strong for it's weight


But seriously what are you covering? Sub systems that extend outside the plane of your robot or just the main systems? We've found that just sturdy supports strategically spaced can protect the robot from balls and the like, if you're worried about arms and what not getting inside and entangled lexan really is the best to use. Very thin lexan is light and still very strong, if you don't have it over a wide area and have some kind of support behind it you could get away with stuff that's an 1/8 thick or even less. The weight is pretty nominal

[Kevin Sevcik]

1/16" Lexan can be pretty darn brittle, though it still might be stronger than any fabric you can find. The best option I could think of would be some kevlar fabric. Here's one source, I'm sure you could shop around for someothers:

Kevlar

Edit:
Just saw something in another thread that could be a good idea. Why not use mesh, like for window screens or something slightly thicker? Search MSC for "wire cloth"

[Ken Ginger]

TYVEK is a trade name for a building housewrap. I believe it is made of spun olefin fiber and is extremely tear resistant. I am thinking of using it or a similar product to cover our bot. The drawback would be the tradenames that appear all over the product.

[Gui Cavalcanti]

Don't use Tyvek! Don't use it! Please!

Sorry. We have two gigantic rolls of plain Tyvek that we're always tempted to use, but never do; it is extremely tear resistant, yes, but it's puncture resistance is terrible. I was able to poke through it with my finger.

We're doing the same thing, M, because our robot's shape isn't very lexan-friendly with all sorts of weird angles. We're using truck bedding tarp; you know, the waterproof stuff made to put over truck beds when it rains? It's light as a feather, and you can't get through it with a pin. It's pretty cool

[Madison]

Originally Posted by Gui Cavalcanti

Don't use Tyvek! Don't use it! Please!

Sorry. We have two gigantic rolls of plain Tyvek that we're always tempted to use, but never do; it is extremely tear resistant, yes, but it's puncture resistance is terrible. I was able to poke through it with my finger.

We're doing the same thing, M, because our robot's shape isn't very lexan-friendly with all sorts of weird angles. We're using truck bedding tarp; you know, the waterproof stuff made to put over truck beds when it rains? It's light as a feather, and you can't get through it with a pin. It's pretty cool

Thanks for the suggestions once more, everyone. I'll definitely see if I can't track down some of these materials locally and put them to good use.

It's being used for wings not unlike what many robots sported last year, and so it has to be resistant to "rigourous robot interaction." We expect that it'll be in a place that lots of robots might want to be, and so we're expecting it to get beaten up badly.

[Amber H.]

M.-
Call Rose City Textiles in Portland Oregon (They should have a white page listing) and see if they still carry a heavy duty rip-stop nylon shell fabric often used in tents and parkas. They are an overstock type firm that specializes in outdoor and sports fabrics. I used the as a resource for tent making some years ago.
P.M. Me if you need some solid instructions on how to give extra strength when attatching loops or grommetts

Dont bother with canvas or denim. Go straight for the rip-stop. It is designed to resist the punctures and tears you are talking about. trust me on this. I have designed children's clothing and outdoor equipment for many years.

[Madison]

Originally Posted by Amber H.

M.-
Call Rose City Textiles in Portland Oregon

Thank you, Amber. That sounds like exactly what I had in mind and Portland is reasonably close. If I had a car out here, I'd drive down there and pick up the stuff myself.

By any chance, do you know how much it may cost, approximately? We're a bit poor as a check we were waiting on hasn't yet arrived, to my knowledge.

[GregT]

Something I've always wanted to try is using layered HDPE as a shell. Collect old shopping bags (the thin noisy ones you get at the grocery store) and layer them to create a protective barrier. This would be a very cheap option, as most people have lots of these bags laying around, would be lighter, and may stop must blunt objects like balls or goals (anything sharp will cut through it).

I really have no idea how this would work, but it's probably worth at least a test.

Greg

[Amber H.]

Originally Posted by M. Krass

Thank you, Amber. That sounds like exactly what I had in mind and Portland is reasonably close. If I had a car out here, I'd drive down there and pick up the stuff myself.

By any chance, do you know how much it may cost, approximately? We're a bit poor as a check we were waiting on hasn't yet arrived, to my knowledge.

Rip-stop usually comes on rolls in widths of 54" to 60" and at RCT can cost anywhere from 50 cents to $10.00 a yard. You should be able to purchase it by the yard. If they give you a catalog to look at, start with the blue pages first (if they still do that) and they will have the cheapest closeout stuff there. Generally though, it's all cheap compared to most fabric stores,.....plus, you can't find that stuff in most fabric stores. It's an independant (cheap) outerwear designer's dream.

Oh and they also deliver nationwide since they are a mail-order oufit.
Ask for samples of "HEAVYWEIGHT, RIP-STOP, NYLON" sometimes they will have the word "MACHO" in the description to indicate strength. I worked with some a few years back and it was like a nylon version of canvas that put regular canvas to shame in a paper thin sheet. You call them, they send you swatches for free, then you order and they ship it to you. You don't have to drive.