Comments | dave_t_lurker: FAIL!

dave_t_lurker

FAIL!

Mar 09, 2008 12:15

*creak-creak*
*ping*
*rattle-rattle-bonk*
*thud*
"FuckTurns out that 84' of 6mm diameter stranded copper wire + PVC insulation is a bit heavier than you'd guess and exerts more stress than self made S-hooks can take. First they creak a bit, then they shear (*ping*), then they and the pulley slide down the roof (*rattle-rattle-bonk*) before finally ( Read more... )

Comments 14

katsmeat March 9 2008, 12:44:15 UTC

Umm yeah... why are you using 6mm, unless you got it for free somewhere. That's about 6.5kg by my reckoning. And the tension to keep it up is goint to be chunky.

Go to Thorns in the City, by Jarrolds. They sell all sorts of hooks and pulleys and tension screws for errecting fences. Just what you need.

dave_t_lurker March 9 2008, 13:20:40 UTC

I have about 400m of the stuff that I got for free, I'd not realised the diameter until it came to putting it up. I was pretty sure it was 3mm stuff I had.

katsmeat March 9 2008, 14:46:21 UTC

Hmmm... some points.

o 400m of 6mm copper wire - 101.33kg

o Current price of copper - around £4800 per ton.

Recommendations:

Have a chat with a scrap metal bloke (try for £300). Then buy 26m of antenna wire from Maplins and all the beers at the next ALUG.

dave_t_lurker March 9 2008, 20:29:18 UTC

Good idea - I'd not really realised the price of copper these days. The part of me that loathes parting with anything "in case it comes in handy some time" is rebelling against the idea of trying to sell it.

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dave_t_lurker March 9 2008, 13:50:08 UTC

cheers

(The comment has been removed)

dave_t_lurker March 9 2008, 13:22:04 UTC

Thanks for the offer - I should be fine. I'm going to scrounge up some more steel bar this week at work and get some much thinner wire. I might scream for help after next weekend though...

caitirin March 9 2008, 13:29:30 UTC

aww rats! Good luck on take two!

dave_t_lurker March 9 2008, 20:29:41 UTC

thanks.

gerald_duck March 9 2008, 13:52:17 UTC

I… think I would guess how heavy 84' of 6mm-diameter copper is, actually. :-p

Also, back in the dusty recesses of my mind's applied-maths filing cabinet is a vague recollection of catenaries. Suffice to say the force required to stretch the thing out approximately horizontal is very much more than its weight.

klonecaid March 9 2008, 13:58:01 UTC

yes, the trick is to have *two* cables, the top one under moderate tension but still a caternery supporting the lower one with 4 or so vertical cables...

dave_t_lurker March 9 2008, 20:26:42 UTC

That's probably total overkill for this situation. Thinner wire is much more sensible.

klonecaid March 10 2008, 17:36:23 UTC

the stress on any cable to get it remotely horizontal over 25m is going to be high, though...

Thread 6