WhiskyFudge Posted January 16, 2008 Share Posted January 16, 2008 We're doing a show in a venue who's only FOH rigging points are vertical bars at the side of the auditorium which look to be simply bolted into the wall. This has been fine previously when only rigging a few Par Can's. However the upcoming show requires 4 MAC 600's which we are not happy about putting on these bars, we feel the weight is too much of an issue. We already have coming in, a pair of portable Aluminium Scaffold Towers for use for follow spots. As far as I can see these are our last options for somewhere to rig the Macs. The Towers do have outriggers on but we're still concerned about rigging a pair of the fixtures horizontally out of the shorter side of the tower. Does anyone have any one have experience in doing such a thing? Can we get away with counter weighting the other side of the towers? Can anyone suggest a way of rigging these fixtures vertically downwards on the towers? Or any form of alternatives? I've attempted to keep the situation simple - but feel free to ask any questions. Thank-you for any help given Link to comment Share on other sites More sharing options...
jimbo7744 Posted January 16, 2008 Share Posted January 16, 2008 WhiskeyFudge, As your probably aware, Scaffold towers are not designed for the purpose of hanging equipment from and I would strongly advise you not to do what you are proposing. The lightweight aluminium tubes are designed for loads to be distributed along to the ends and not from the middle or pulling in other directions (with the exception of the ladders and end structures. If you were to out-rig on the ends, the force you would need to tighten the clamps would just crush the tubes and leave you with a very expensive repair bill. F.O.H lighting towers you may have seen, would be constructed of steel 'builders' type scaffolding tubes and probably steel/ali deck. How high are you looking to build the towers? Even using a followspot on a scaff tower only 1 section high, would still have a fair amount of movement if the operator moves, and create shaky results. If the towers only need to be 6 foot high, is using steel deck and scaff tubes (with appropriate cross-bracing and guard rails etc etc) not a possibility? Builders scaffold tubes can be rented at as little as 2p/foot for a week. If you have some steel deck platforms and a chop saw to even out the differences in heights (with the permission of the rental company) this could still work out relatively cheap and be a lot more stable and suitable. (with the appropriate method statements/risk assessments etc) Link to comment Share on other sites More sharing options...
WhiskyFudge Posted January 16, 2008 Author Share Posted January 16, 2008 The towers previously have been 2 + 1/2 height panels height (my apologies off the top of my head I'm not sure what height that gives). The boards are placed on the top of the 2nd full height panel. The tower movement has not previously been an issue during the shows (obviously there is quite a bit of movement when climbing) The crushing of the tubes had been something I'd not considered. Thank-you for that valid point. As a variation of this theme would hanging a piece of ladder truss/steel scaff bar to the side of the tower and rigging the fixtures to that be an option? Obviously attaching box truss to the side would allow the fixture to hang vertically down, but I would sense there are too many forces in the wrong directions there - even with the out riggers on? Whilst I feel I could build a custom platform out of steel myself as suggested, I would not like to consider myself competent enough to build something of this sort. Is there a company in West Yorkshire who would offer such a service? Link to comment Share on other sites More sharing options...
paulears Posted January 16, 2008 Share Posted January 16, 2008 Would it be possible to use vertical truss sections next to the wall boom that you're unsure of. If the ground provides support, then the boom would only be required to prevent the truss falling sidways - a much lighter load. Much depends on the available support. other than that, why not get a scaff company to build you a more permanent structure that the follw spots and mcas could work from - although MAC600s from followspot distance might better be replaced with some kind of moving head profile that you could simply defocus for a wash? From follow spot distance they'd be rather wide? Link to comment Share on other sites More sharing options...
WhiskyFudge Posted January 16, 2008 Author Share Posted January 16, 2008 Would it be possible to use vertical truss sections next to the wall boom that you're unsure of. If the ground provides support, then the boom would only be required to prevent the truss falling sidways - a much lighter load. Much depends on the available support.This is an interesting idea. Logically it would take the raw weight issue out of the equation. Obviously if we horizontally rigged these there would still be a large force trying to trip the truss over. Have you any idea what sort of forces anchoring this to the bar would be? other than that, why not get a scaff company to build you a more permanent structure that the follw spots and mcas could work fromThis is something I'm going to look into as suggest by jimbo7744. But I'm quite kean on getting as many idea's as possible here first. - although MAC600s from followspot distance might better be replaced with some kind of moving head profile that you could simply defocus for a wash? From follow spot distance they'd be rather wide?Point understood - but we're still only talking distances of 7m to the front of the stage. I've attempted to similar things over the same sort of distance before and was not impressed with the results. I will however be talking to the hire company regarding the lens depending on their final position. Link to comment Share on other sites More sharing options...
jimbo7744 Posted January 16, 2008 Share Posted January 16, 2008 The forces you would be putting on the scaff tower by attaching truss to the side could make it unstable and you would have the problem of how to attach the truss to the tower without causing stress on the frame. I second Paulears suggestion of attaching a piece of floor mounted truss vertically to the existing bar's. You could do this with some double Doughty clamps http://www.doughty-engineering.co.uk/cgi-b...showprod_T24800 and possibly use some ratchet straps to pull the truss tight to stop any movement when your mac's are wiggling. I don't personally know of any specialist rigging companies in West Yorkshire, someone on here might though. But if you have the decking, then why not call up a couple of local scaffolding firms and inquire if they would be willing to undertake the construction, and might even give you a discount for an advert in your marketing?! Link to comment Share on other sites More sharing options...
peternewman Posted January 16, 2008 Share Posted January 16, 2008 I second Paulears suggestion of attaching a piece of floor mounted truss vertically to the existing bar's. You could do this with some double Doughty clamps http://www.doughty-engineering.co.uk/cgi-b...showprod_T24800No, don't use scaff clamps, they don't spread the load enough and will damage thin walled truss, they're really only designed for scaff. You want to use something from this range instead, either swivel, parallel or 90° depending on the angles involved. Link to comment Share on other sites More sharing options...
jimbo7744 Posted January 16, 2008 Share Posted January 16, 2008 My bad! Peter is right, I was in a rush on the way out and the scaff clamps not double big ben's were the first one's I came across. Must remember to not post in a rush! Link to comment Share on other sites More sharing options...
uberyakker Posted January 16, 2008 Share Posted January 16, 2008 as you are now thinking of bringing a peice of truus that runs from floor to the required height why dont you hang the mac's on a t bar off the top of this?then all the weight is on the upright and the wall bar is only suporting it from falling over thus reducing the force onto these bars? Link to comment Share on other sites More sharing options...
WhiskyFudge Posted January 16, 2008 Author Share Posted January 16, 2008 The T Bar idea was where I'd got to my self. It is certainly looking like a very good solution - in fact I'm stuggling to think of a reason against it! I'm still open to any other ideas - but thank-you very much for all the ideas/comments so far. Link to comment Share on other sites More sharing options...
Congo Posted January 16, 2008 Share Posted January 16, 2008 Might I suggest some thing like these manfroto Black magic http://www.manfrotto.com/Jahia/news/site/m...d/15343/lang/en many versions like it out there I belive DBN in manchester has some, put a T bar on and wind up, at least to legs of the base could live under the tower if set up as a x not a + and saves trying to lift what ever units you use to the desired height, they might even allow you to get them higher Mark Link to comment Share on other sites More sharing options...
Simon Lewis Posted January 17, 2008 Share Posted January 17, 2008 as you are now thinking of bringing a peice of truus that runs from floor to the required height why dont you hang the mac's on a t bar off the top of this?then all the weight is on the upright and the wall bar is only suporting it from falling over thus reducing the force onto these bars? This might well work, but a) you need to have a suitable means of attaching the cross bar b) it needs to be able to take the weight of the fixtures c) the further out you extend the bar, the greater the horizontal pull on the wall bar (i.e. not all of the force is acting downwards) and d) you should check that the truss is OK to be used in this vertical fashion.... Link to comment Share on other sites More sharing options...
uberyakker Posted January 17, 2008 Share Posted January 17, 2008 sorry I meant that if you hung the macs either side of the upright then the forces should balence out. also to the joining point there is purpose made truss peices for this application.what orientation to the stage are you planning on having this cross bar? I think that if it ran parrallel to the stage it would be better so that both macs can cover all teh stage? Link to comment Share on other sites More sharing options...
WhiskyFudge Posted January 17, 2008 Author Share Posted January 17, 2008 I'd like to thank everyone for their input. We've now developed this idea into a goal post type structure which will also allow us to add the few generic's we've also got to go in a similar position. The structure will then be attached to two of these vertical bars, hopefully spreading the load further. Link to comment Share on other sites More sharing options...
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