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homemade truss

Discussion in 'General Advice' started by ccfan213, Jun 14, 2005.

  1. ccfan213

    ccfan213 Active Member

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    a while ago i made a truss type thing for a photo shoot i was experimenting with, my other hobby is photograpy. anyway, my photo lights all have stands, but i wanted to use clamplights for additional lighting. i built a frame out of 2x4 that is probably about 8 feet tall and 12 feet wide. it has three 2x4s extending across it to hang lights on. it stands on two homemade sawhorses. it is now sitting in my garage unused. my question: could i use this or some sort of cheap pipe from home depot to make my own truss or trees? my stage has horrible frontlight positions and i am looking for new and very cheap options. has anyone ever done this before? do you have any suggestions on how to build more truss?
     
  2. jonhirsh

    jonhirsh Active Member

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    depends i always use a general rule do you feel safe standing under it with a full load on it affter it has hung for a few hours. if yes then you should ask your self are you using rated parts for the purpous if its cheep you probably havent so i would say no but if you have found a welder who will do it and is willing to take the liability and is cool with the possiblilitiy of being sued for a accident based on the possibility that his welds may break if you find one and the right rated materials for a cheep price yah do it heck if i could find all that i would


    JH
     
  3. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Now I am certainly no expert when it comes to rigging but for me - I think that there are too many safety risks involved here. Especially if you want to hang this trus.

    You may be a very competent welder but unless you can weld aluminium, anything that you build is going to be very heavy.

    Trouble is that all it takes is one thing to go wrong and you will be held liable.
     
  4. jonhirsh

    jonhirsh Active Member

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    tuss is made of steel as well even if purchased from a dealer but it is usualy speced for installs
     
  5. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Yes - you are correct, but we see less and less of it being used these days, even on installs, which tend to be aluminium.

    My point is more to do with liability should the trus fail. Should the anchor points fail because the trus exceeds them, then i am sure that would also have issues with regards to the liability.

    Generally, I think we are on the same page here and I think your previous comment about how safe would you feel standing under it would support this.

    But like I said - I am no rigging expert but it is not something that I would be rushing to do as I think there are too many variables that could go wrong.
     
  6. sound_nerd

    sound_nerd Active Member

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    I'd stay far far away from making your own truss. I've seen mobile dj's use sections of "tv tower" (antenna tower..) as truss. That worked okay, but you could see it bowing with just a few fixtures on it. There is inexpensive truss to be had, try www.cheaplights.com or similar places.

    There is too much to risk by building, and using/flying your own truss. The only time I could ever support that type of project is if it was for display only. For example podiums, coffee tables, stools....etc..
     
  7. ccfan213

    ccfan213 Active Member

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    i didnt mean to hang it, i meant more as a freestanding thing, like a dj truss size frame to hang lights on. the one i made out of wood is pretty sturdy, i would not hang fixtures on it out of fear of the wood snapping, but i dont see why if i were to make something out of 4x4 that was freestanding and not over people's heads it would b a problem.
    on a simlilar note, i have 2 onstage stands for my PA at home, could i hang fixtures on this?

    i have no good frontlight positions and i am trying to figure out a way to create some without cost to the school, because they wont let me. the local home depot and lumber yard have been good about donations in the past so i was hoping to do something with that.
     
  8. len

    len Well-Known Member

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    Call your insurance agent, or if this is going into a government run building (such as a school) call the corporation counsel. Explain that you'll be making something yourself, that it will be suspended in air, with additional weight on it, and electricity connecting the fixtures. They'll ask if you have any qualifications, training, etc. in building this stuff. If the answer is "no" then they'll probably advise against it. And if you proceed anyway, and there is an incident, the liability will be completely yours. Until they make you take it down.

    Trussing is made with strict requirements for a reason. You should try and get a copy of the latest Pro Sound and Lighting News, which has a comparison chart of trussing.

    I think this is the link http://www.plsn.com
     
  9. jonhirsh

    jonhirsh Active Member

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    i understand now what you want you want to make a tower not truss per say but you want two of these "towers" on sl and sr that you can clamp a few lights from they would be vertical and freestanding

    did i get his right ?

    if i did what i would say is that when i use truss in this manner we use 50 to 60 pound base plates on the bottom to stop it from tipping over, never under estimate the power of stupid actors and such. in one case i did a show where we had four four foot plates bolted together for one pice of truss it weighed almost 300 pounds i would say get your self some decent weights or sand bags to weigh down the bottom of your contraption because lights are heavey and they are not going to be placed on the truss in a even load no matter how hard you try


    if i am wrong

    you will have to draw some sort of diagram to explain what your talking about


    i think using wood for this construct is a bad bad bad idea wood and power dont mix well neather do heat and wood just get some steel and some welding gear given you know how to do it and build some towers use 2 inch pipe and if its in a theatre use black pipe so as to blend it in
    if its not going over an audiance and you would feel safe standing near it i dont see a problem

    JH
     
  10. ccfan213

    ccfan213 Active Member

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    yea u got it right, more of a tower to hold fixtures. getting weight should be easy, i can use extra weigh from the fly system and if thats not enough i can steal from the gym.
     
  11. ship

    ship Senior Team Emeritus Premium Member

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    You would need to have an entertainment truss welder's certifications as seperate than even welder's certificates and X-Rayed welds on the manufacturer level, much less engineering and loading certificates about a truss system - including size and weight of base. Or the question of even leverage dependant upon weight of fixture, it's distance from the ground and how far out it is as factoring into the base support in question even if only a tower.

    In the case of the speaker stands, the speakers are perched in a balanced position above the stands. Force is only in a downward direction with only a little built in for sway brace since it's not out of balance. Attempt to use them as a boom, it depends upon the combination of weight and leg length for overall stability of the top heavy speakers as to how far out of balance you are now safe in throwing them off.
    Walk across the carpet in your room adjacent to the speaker and it could make it fall over. On the other hand, it could be just fine. (Safety cabling booms and when possible stands to the roof or wall is always a wise tactic.) Might recommend hanging the fixture directly over one of the legs, but also remember that the stand is engineered to support a weight above it only on the same axis plane perpendicular to the floor. Clamping pressure on something only meant to be strong in one dimension could be like crushing a coke can.

    Try the famous experiment. Stand on an empty coke can than have someone just touch the side of the can under you.

    This is a similar reason to why a truss that is radio tower when used in a different axis might not be very strong even if still a truss.

    Lumber - avoid it if possible for something perminant and not covered by flame resistant materials or for lighting equipment.
    Welding your own, depends - but only in a professional setting with a certified welder authorized by the school to weld.

    In the end, I like Len's idea but might take it one step further. Once you present your need for the lighting position, and you sheepishly pose your option for it to be rejected, you bring a price quote out of your pocket - that is now much more reasonable in cost to have done given the problem presented and it as the best way to get done. Price must be reasonable in symplicity.

    Just a question than of to what extent you want this done. Could be as simple as a pipe with various forged steel (not malleable or cast) elbows and parts bolted to the wall. Simple C-Shape say out from the wall by 12", neat and less obtrusive than some lumber tower. Could be a professional truss stand but it than can be tripped over by the audience. Could be a pipe running floor to ceiling that's using again forged or designed for such stress and loading parts to mount and couple it. If nothing else, a 40# boom base, a pipe and have a certified welder weld a chain link to a pipe cap. This or drill it for a drop forged eye bolt. Than wire rope off to the ceiling.

    Problem with stage weights or sand bags in other than a temporary situation is both because it adds height to what you don't want someone to be tripping on, and they are not a perminant - other than most often in a hack way solution to your problem. What happens when the sand bag gets a hole or someone needs a door stop? Your temporary fix for adding weight is than very temporary and dangerous.

    Keep thinking, care is good, just a question of time in having experienced solutions and learning about enough options at times before you do come up with a solution. Asking here and everywhere and anyone you can is also good.
     
  12. BillESC

    BillESC Well-Known Member Premium Member

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    A large part of the cost of trussing is made up of certification and insurance.

    Truss manufacturers have their products certified by structural engineers with a minimum of a 4 to 1 safety factor. The manufacturers also carry massive amounts of liability insurance since the chance of failure, however slim, invites hugh lawsuits.

    IMHO, it is simply not worth a few dollars savings to expose oneself to such a potential disaster.
     

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