Steel angle iron vs square bar

I recently put up a couple of standard 2m fence panels; they stand at the edge of a reasonably substantial drop though, so it's really important they don't get pushed over (TBH I think I now regret not having erected steel railings instead).
I've decided that it wouldn't be a bad idea to attach a length of mild steel to the reverse (hidden) side of the fence, just below the top; ie screw a 4m length to the three fence posts, so it would act as a rail and prevent the fence panel from breaking and falling over the edge if someone fell really heavily against it.
Question - what would be best to use: angle iron or solid steel bar of comparable substance/cost - eg, say 20x20x3mm angle iron vs 12mm solid bar? (I favour the angle iron in the sense it will be easier to get through with my hand drill!)
Also - where, as a civilian, am I best going to buy this sort of stuff? I don't normally 'do' metal; the last time I bought some steel years ago I went to a local steel stockholder and got royally ripped off I reckon...
--
David

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On 27/06/2013 08:16, Lobster wrote:

Probably more effective to put up a post and horizontal rail fence inside the panel fence, so that if anybody falls, they hit the rail and not the panel. Following health and safety guidelines for workplaces, such a rail should be 1.1m high and there should be a second rail at half that height.
You could do that in wood if you prefer to work in that material, but do make it substantial enough to take a heavy falling person. 3 inch / 75mm is probably the minimum size of timber to use and the posts need to be really solidly mounted.
If you prefer the steel idea, I don't see the point of putting it at the top, away from the probable impact zone. It would not stop somebody breaking through a light fence panel there. It should be mounted where the person is likely to fall against the fence, i.e. the same as the post and rail fence rails.

Angle iron will have greater stiffness.

If you need a 4m length (or two) then a steel stockholder is probably your only choice. You will likely find it cheaper to buy a 6m length and cut it yourself than to pay a cutting fee and get a 4m length.
Colin Bignell
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On 27/06/2013 09:04, Nightjar wrote:

To get a feel for price, there are plenty of suppliers for angle iron and steel box section on eBay. The longest stock I spotted in a quick look was 2.5 metres but ISTR that you can get 3 m or more.
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On Sat, 29 Jun 2013 22:22:43 +0100, newshound

I've found www.metalsupermarkets.com not too bad. Although their asking prices are a little high, you can often haggle a bit with the staff. At least they have a good range of stuff in stock at their various branches.
[No connection with this organisation.]
--
Frank Erskine

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Not very impressed with their "store finder" since it claims my nearest one is in London, Ontario, Canada, some 3000 miles away.
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Today is Sweetmorn, the 35th day of Confusion in the YOLD 3179
RIP: Richard Burton Matheson (February 20, 1926 – June 23, 2013)
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On 29/06/2013 22:22, newshound wrote:

Buying from industrial suppliers, steel section will usually be supplied in 6m or longer lengths. An alternative for this application, if rather heaver section is used, could be aluminium, which normally comes in 4m or 5m lengths.
Colin Bignell
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Lobster wrote:

As said, angle iron better than solid. You don't need to go the full height; posts tend to break at the base as that's the weak point with the rest of it acting as a lever. Anyway, it only really works if someone throws themselves at the post; panels tend to be so flimsy I'd expect a Tom and Jerry style person-shaped-hole if someone fell against it while the unreinforced post wouldn't be unduly worried.
Google for Metal Supermarkets. Dealt with them when I had one close and their pricing was pro-rata for small bits.
Alternatively, an idea having just hit, how about steel wire running from end to end behind the panels (since there's a drop, I assume there's no one the other side to moan about aesthetics) in the same vein as motorway fencing? Attach to each post at similar positions to Colin's rails and a) the force[1] is distributed among all of the posts and b) they'll stop someone going through the panel. Be a lot cheaper than a full handrail (S'fix do it in various sizes and 25m lengths for buttons)
Scott
[1] ie drunken party go-er.
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On Thu, 27 Jun 2013 08:16:13 +0100, Lobster wrote:

Over 2 m both will bend when pushed in the middle but the angle iron less so. TBH gut feeling says that 20 x 3 angle ona 2 m span will just buckle if a decent sized person fell heavyly onto it. I think 40 x 5 angle or something of that order would be more suitable and mounted at the height suggested by Mr Bignell. A stong member at 6' isn't going to catch someone crashing straight through the fence panel...
Post and rail stock (horses, cattle...) fencing uses roughly 4 x 2 timber rails at 6' post spacing. Couple of those may well be cheaper and easier to handle/fit than hefty lumps of steel.
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Dave.
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On 27/06/2013 09:53, Dave Liquorice wrote:

Not necessarily a bad thing, providing the fixings hold and the person does not fall right through. A rigid rail would have advantages if people are expected to use it regularly, but for something that is only supposed to guard against an unlikely accident, some give might soften the landing a bit.
The suggestion of series of tensioned wires is a good idea and, if put on the inside of the fence, they could be used to train plants as well as providing security.
Colin Bignell
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20 x 20 is a bit floppy, you may want something a bit heavier and/or use square hollow tubing instead which is more rigid.
Lot's of steel stock pricing is driven by the weight of the steel in it unless the complexity of the manufacture adds significantly to that cost. That should make angle the cheapest option with RHS a bit more I would expect.

If you have a branch nearby, I can recommend Metalsupermarkets, reasonable pricing and no minimum order.
http://www.metalsupermarkets.com/msc-storefinder.aspx?map=UK&region=UK
Their site used to be an absolute shocker but I see it has been improved and the even claim online ordering but the delivery would probably be stiff.
Even if you're not close, you could get a price over the phone from them and then tout it around local steel stockholders in your area. With those however you may come up against a minimum order charge.
I agree with Colin's suggestion that the bar should be at handrail height but I'm guessing that you might have access difficulties getting to the back of the fence over the dropoff<?>.
Given that, you may want to change direction a bit and add a straining wire to the front of the fence at handrail height instead. I've used 6mm braided galvanised steel wire in tensioned fencing, it's very strong and looks nicer than plain fence wire. You could drill the posts and thread through to firmly link it to the structure. I thought you might end up pulling the end posts in a bit when you tension it (with straining screws) but as you have panels in the gaps it should just squish them up a bit. The benefit of this system is that the parts are cheap and light so easy to mail order - ah, also avail from toolstation:
http://www.toolstation.com/shop/p50350
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fred
it's a ba-na-na . . . .
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Just a thought, if you are likely to have kids running about then more wires might be better, say 3 equally spaced off deck up to a metre?
--
fred
it's a ba-na-na . . . .
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Garotte, you mean?
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On 27/06/2013 08:16, Lobster wrote:

If you do use angle iron, consider fixing it so that its surfaces are at 45 degrees to horizontal - e.g. drill through the 90-degree bend and screw to the fence/posts like that. Advantage is that it will drain well and be less prone to rusting through in short order.
--
Rod

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On 27/06/2013 08:16, Lobster wrote:

In that situation, I'd just attach some chain-link fencing to the back using lots of staples. Then even if someone makes a nose-dive through a panel, they can't miss the safety net...
Cheers,
Colin
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I think chain-link fencing would be a better idea as long as each end is securely fixed http://www.jacksons-fencing.co.uk/security-fencing/roll/chain-link-pvc/roll-chain-link-pvc.aspx-
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On Thu, 27 Jun 2013 08:16:13 +0100, Lobster

Farmers' Yard type suppliers. Farmers uses for steel bar, strip, angle and tube are many and they, being tight feckers, will always look for the best prices.
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