TomHoward Posted March 16, 2015 Share Posted March 16, 2015 Evening all We have a regular use where we smarten up a sports hall a bit, and we use tripod stands with 20ft poles (stands at 3rds in so it does't bow) and tabs. Stands are a mixture of 20ft x 10ft height and 10ft x 10ft square. We are thinking of smartening this up a bit with tank traps rather than tripod stands (as they won't poke in the tab as much), and Flints suggests traps to be used for temporary masking etc, but what is anyone's gut reaction to the stability of this? Obviously subject to risk assessment and situation etc but be interested to hear if anyone is regularly using these kinds of sizes of structure with tank traps. Link to comment Share on other sites More sharing options...
IRW Posted March 16, 2015 Share Posted March 16, 2015 Evening all We have a regular use where we smarten up a sports hall a bit, and we use tripod stands with 20ft poles (stands at 3rds in so it does't bow) and tabs. Stands are a mixture of 20ft x 10ft height and 10ft x 10ft square. We are thinking of smartening this up a bit with tank traps rather than tripod stands (as they won't poke in the tab as much), and Flints suggests traps to be used for temporary masking etc, but what is anyone's gut reaction to the stability of this? Obviously subject to risk assessment and situation etc but be interested to hear if anyone is regularly using these kinds of sizes of structure with tank traps. As I'm sure you are aware, Tank Traps are rather heavy, as are scaff poles, and such as system can take time to put together- if you are buying for regular use, have you considered a proper pipe-and-drape system? You'd probably need to insert some extra uprights, but it sounds like the system for the job! Link to comment Share on other sites More sharing options...
TomHoward Posted March 16, 2015 Author Share Posted March 16, 2015 Sorry, by regular I mean about twice a year, just that it's not a one-off. We already have everything else on the shelf so I could purchase 8 or so tank traps which would be about as many as we would need - they would double up for other uses outside of those jobs as well but pipe and drape might be a bit specific. Link to comment Share on other sites More sharing options...
jonathanhill Posted March 17, 2015 Share Posted March 17, 2015 If you are considering the Doughty tank traps, which have a 600mm square base, then using aluminium scaff with a couple of stage weights on the tank trap should be fine at 10' high. Link to comment Share on other sites More sharing options...
TomHoward Posted March 17, 2015 Author Share Posted March 17, 2015 I am considering doughty, I'd look at either buying the materials and welding them up myself or getting a local fabricator we use if I want an even better job, but to be honest with the price of steel, and then if you get it powered coated as well I can't see it costing much less than a tank trap to do a nice job Link to comment Share on other sites More sharing options...
the kid Posted March 17, 2015 Share Posted March 17, 2015 I looked at the price of making some a few years ago, a sheet of steel was going to cost me about £80 + box steel for the pipe (box was WAY less than round) It came to about £100 not including labour, the aim was to have the engineering department do it for beer. This was a few years ago and its quite a bit more now I imagine. The main issue was cutting it, I think a tanktrap is 5mm and that was not super easy to cut without some hard core tools. Link to comment Share on other sites More sharing options...
timsabre Posted March 17, 2015 Share Posted March 17, 2015 The doughty tanktraps also have a slot in the base allowing them to be slotted on top of each other for reduced storage space, otherwise they are horrible to store. This would be unpleasant to have to cut DIY. Link to comment Share on other sites More sharing options...
Jivemaster Posted March 17, 2015 Share Posted March 17, 2015 Getting the cut steel delivered isn't hard welding the socket to the plate needs a good welder and maybe a fillet in there tor support. However storing them between uses will be a pain. Getting the slot cut will be demanding. Tank traps simply don't fold! Link to comment Share on other sites More sharing options...
Dave m Posted March 17, 2015 Share Posted March 17, 2015 cpc were doing tank traps pretty cheaply last time I looked. They won't wear out and £100 spread over (5 years twice a year) is a tenner a unit. Hire is maybe £7.50? per week? Link to comment Share on other sites More sharing options...
TomHoward Posted March 17, 2015 Author Share Posted March 17, 2015 Yeah the delivery costs with hire are where it stacks up though.We're much more likely to buy than fabricate for all the reasons suggested and I can't imagine it would be much cheaper to fabricate even if we could cut it. (We can weld and we have a guillotine but won't cut that steel and definitely not a neat slot)Since no one has seems overly horrified by the idea of a 10'x20' tab on tank traps I guess the doughty ones are the order of the day On the subject of stage weights, any tips for alternatives to the Flints traditional weight? If I need a couple per tank trap they'll add up as wel so if anyone is using sports weights / market weights etc that suit I'd be interested Link to comment Share on other sites More sharing options...
GR1 Posted March 17, 2015 Share Posted March 17, 2015 I can't see why anyone would want to build tank traps unless they have an engineers workshop available to them. It is possible with quite a bit of hassle to weld them up and save a few quid but to use them professionally you have to be able to certify them as fit for purpose. Flints can do that - I suspect that many of us probably can't. Link to comment Share on other sites More sharing options...
Dave m Posted March 18, 2015 Share Posted March 18, 2015 I use loads of 5ltr/ 1 gallon old screenwash containers as weights. I fill them with sand and they weigh aprox 8 kg.Would water also be an option ( it is lighter but you don't need to take it with you)Doughty weights are 12 kg I think so 3 sand containers to 2 stage weights Link to comment Share on other sites More sharing options...
librarian28 Posted March 18, 2015 Share Posted March 18, 2015 you have to be able to certify them as fit for purpose.I'm not sure what a 'fit for purpose certificate' looks like. Have you got a sample example? Link to comment Share on other sites More sharing options...
TomHoward Posted March 18, 2015 Author Share Posted March 18, 2015 Well there's a slightly clearer liability issue if they're off the shelf. In my experience not looking dodgy is half the battle, which is why I'd want to power-coat them etc so I can't see it being cheaper than buying (or certainly not worth the saving) It's that lack of detail though about swl / tipping forces etc that prompted me to ask Link to comment Share on other sites More sharing options...
timsabre Posted March 18, 2015 Share Posted March 18, 2015 Well there's a slightly clearer liability issue if they're off the shelf. In my experience not looking dodgy is half the battle, which is why I'd want to power-coat them etc so I can't see it being cheaper than buying (or certainly not worth the saving)It's that lack of detail though about swl / tipping forces etc that prompted me to ask I have mostly used them for side lighting with fixtures side-mounted on vertical booms, the tipping forces there are quite high but they are very stable with a few weights on the base. So I wouldn't be worried about a 10ft high drape which will have central loading. Unless there are risks of drunk people trying to pull it over or something, even then I think it would be fairly safe. Jivemaster is right about storage/transport. They take up a lot of space, even the Doughty stacking ones. Link to comment Share on other sites More sharing options...
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