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lexan \ polycarb
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timmeh
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lexan \ polycarb

Dose anyone know where i can get some 3mm lexan from in vic or anyone have some forsale

How heavy is it compared to ali?
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Post Tue Aug 24, 2004 5:42 pm 
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Glen
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bunnings has 3mm thats shockingly expensive.

dotmar, and cut to size also supply it i believe.

well the density of lexan is 1200kg/m^2 and 2768kg/m^2 for ali IIRC
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Post Tue Aug 24, 2004 5:59 pm 
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timmeh
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Thanks so i take it its half the weight of ali
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Post Tue Aug 24, 2004 6:01 pm 
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Glen
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yeah there about, 3mm is very thin and flexible, i wouldnt use any thinner than 6mm in any of my robots.
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Post Tue Aug 24, 2004 6:10 pm 
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timmeh
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Im getting very tight on weight on my 12kg bot i am thinking if lexan is half the weight or less then half i can use 6mm lexan insted of 3mm ali those are the only two options i have at the moment or maybe 4mm lexan

3mm lexan 3mm ali how strong is it compared to ali?
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Post Tue Aug 24, 2004 6:14 pm 
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Glen
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3mm is flimsy as hell. dont rely on it for any form of structure. it will only work armour (and wont do that well when we have such high power spinners.)
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Post Tue Aug 24, 2004 6:22 pm 
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timmeh
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as long as it is half the weight as ali i will go the 6mm but where can i get some cheaper then bunnings.In vic around the baywater aria or dose anyone have any forsale?

It is for armor but only half the bot is open for damage realy so 3mm on top and bottom with 6mm on back and front might be ok to save weight
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Post Tue Aug 24, 2004 6:25 pm 
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kkeerroo
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Hey Glen, stop putting down the plastic robots. Very Happy

I have built both The Aggressor and Adversary out of nothing but 3mm Polycarb. I do use small 50mm long sections of ali L-bracket to hold the polycarb together with either bolts or pop rivits, but the main structural strength is the polycarb. Yes the frames do bend, but I've been bouncing those robots off wall and other robots without much trouble. And yes polycarb will crack if you don't prepare it. When the leg snapped of The Aggressor the crack propergated from a sharp corner which I hadn't rounded and the crack at the front of Adversary was from a rivet hole I hadn't de-burred due to running short of time.
On the other hand the same hit the cracked to polycarb on Adversary also hit the front panel dead on which deformed over 300% !!!!!!! I measured the bump as 9mm high, without penertration. That same sort of hit penertrated Sorry's 3mm ali.
A hit from Annihilation on The Aggressor cracked one of the cast steel bearing blocks, but the the hit beside it only went 2mm into the polycarb.
And Polycarb robots look cool.



By the way Lexan is an American brand name and I havn't seen it sold in Australia, where as Bunnings polycarb which is what I use is Macralon which is a British brand name. Do you drink cola or Coke?
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Post Tue Aug 24, 2004 9:50 pm 
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Waddy the phoenix



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yeah there are plenty of mobs in australia that sell lexan but its practally the same stuff realy
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Post Tue Aug 24, 2004 10:56 pm 
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dustpanboy911



Joined: 15 Jul 2004
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Lexan

On my first two bots I actually used lexan. I quickly figured lexan is much weaker than most aluminum and if possible should be used for the top and possibly the bottom of the bot. If you can stay away from lexan then go for 2024-T3 aluminum. That is the best stuff i've seen! I have noticed that under hard impacts the lexan can crack. UHMW is the only plastic I really use. Most people know it can take an unlimited impact without breaking and WONT CRACK, at all. Saws are a bit of a concern but not too bad if you use a little bit of aluminum behind it. UHMW is also lighter than lexan and can get spinning weapons jammed into it. On my 5.5 kg bot I use 25mm (not a typo) UHMW on all sides with a 2.5mm titanium on the front and back to prevent anything to get through. So far nothing has been able to do any significant damage. On my 6mm lexan version it got cracked and bent, not a good thing!
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Post Wed Aug 25, 2004 9:02 am 
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timmeh
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KKEERROO

Would you say 3mm lexan is better then 3mm ali for armor as long as you round the edges and remove the burs from drill holes
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Post Wed Aug 25, 2004 5:08 pm 
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kkeerroo
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I wouldn't say anything is better than something else as armour.
it is another option tho.
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Post Wed Aug 25, 2004 6:06 pm 
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timmeh
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Would 10mm polycarb be good for a robots frame?
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Post Sun Oct 10, 2004 12:43 pm 
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Glen
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yeah for a frame it would be alright. i use it for the lid and base on cobra because it is just so light yet ubelievably stiff.

just make sure nothing can hit it directly because it likes to crack.

oh yeah and remember, everything must be deburred and countersunk and no corner can meet at 90 degrees
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Post Sun Oct 10, 2004 1:27 pm 
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colin



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i don't see it being good for a frame, too likly to crack. how would you join pieces together?

Post Sun Oct 10, 2004 2:07 pm 
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