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looking on the net ive found sheets of 2mm NS4 Grade Aluminium at 500mm x 500mm for under £20, How good is the NS4 grade and how good is that price, and more importantly is 2mm strong enough or do i really need something thicker.
I was reading an older post on here about polycarbonate and how drilling causes microscopic cracks etc etc, and its kinda put me off polycarb, aluminium must be much simpler to work with, and stronger ?
For chassis or armour? Polycarb can be easier to work with for a chassis pieces but I advise you use ali for armour.
2mm wont be anywhere near enough, for armour you have to look at least 6mm to survive any spinners and at least 4mm for a chassis. Try using HDPE or polypro, these are both similar and dont have the problem of cracking, it can also be heated to either melt it together or bend it.
ok can anyone tell me if this is a good kinda of polypropylene http://www.altecweb.com/home.asp?cat=category3800http://www.altecweb.com/home.asp?cat=category3800
Andrew,
Yes, that is a reasonable grade of polypro.
As another option you may want to look at nylon 6. I use 12mm sheet for all the internal bulkheads/bearing mounts and armour mountings in Pillow Torque. Its so easy to cut and can drilled and tapped with no problem.
My personal view is that as a construction material its far better than polypro, and because of its very good restance to high velocity impact it would also make very effective anti-spinner armour. Out of intrest the tensile strength @ yeild for polypro is around 34 MPa and around 84 MPa for nylon 6.
Although I believe that it does weigh slightly more than polypro.
RS Components have a good range of sheets and bar stock.
(Just somthing else for you to think about!:) )
I used Nylon 6 for my bmx seat post:) worked very well and never broke or bent after the huge jumps/landings and crashes it has taken. Although if it gets wet it seems to soak up water and expand rather alot as i left my bike in the rain and had to remove the seat post by bolting the frame to the floor, and getting a forklift truck on my seat lol.
oh, and i dont really see a huge need for more than 6mm ali armour and 4mm ali chassis. Venom has 3mm to 4mm ali for the main chassis and that stands up fine. espesially with the stress that goes through the arm, tonnes! for chassis i recommend around 3mm, and for armour theat polypro, simple and easy to use.
I am thinking of using 5 mm aluminium for my next feather. It will be both bent and welded to shape. What grade is the best? What other armour would be comparable to this?
Alpha uses 5mm 6082T6 for base and lid.
6082 T6 seems to be the one to use. Its easy to get from the likes of Technobots, also its not too hard that it just cracks when it takes a big whack like 2014 does, but its not too weak that its pointless either. The one to go for.
Mr Stu
6082 welds nicely but be careful folding it as it may fracture.
With aluminium everything is a trade-off between hardness and flexibility.
The weakest (least hard) is a grade called 6082 which you usually find these days heat treated to a level referred to as T6. Its typical mechanical properties are below (based on a 6mm sheet) :
Tensile Strength - 310Mpa
Elongation - 10%
Hardness - 94HBS
The next level up from 6082T6 is 2014T - this is where you start to get a material that is used in aircraft production. Its significantly stronger than 6082T6 as you can see from its tensile strength and significantly harder, however the elongation figure which shows how much it will bend before failing is lower. Vortexs chassis is made from 2014, as are a number of internal parts in Storm II
Tensile Strength - 450MPa
Elongation - 7%
Hardness - 135HBS
The hardest (yet most brittle) is 7075 whose hardness is approaching that of some grades of Titanium. This is an extremley hard relativley tough material. Storm IIs wheels and also its lifting arm are both made out of this material where we needed exceptional stiffness and strength.
Tensile Strength - 540MPa
Elongation - 7%
Hardness - 163HBA
Hopefully that should give some insight into the various grades. 6062T6 is certainly the cheapest and one you can weld with, but where appropriate grades like 2014T and 7075T really allow you to benefit from their properties.
Ed
http://www.teamstorm.comhttp://www.teamstorm.com
Thank you all.