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steel tubing to replace lumber

Discussion in 'Question of the Day' started by ship, Feb 4, 2007.

  1. ship

    ship Senior Team Emeritus Premium Member

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    It's often said that a 16ga. 1x1" tubing is as strong as a construction grade 2x4. How is that - in a certain direction, with a certain structure to it? explain.

    Consider if you will a 4x8 platform that has a 3/4" plywood top screwed to a 1x1 box steel frame done in the same way of fraiming - certainly this wouldn't be as strong or we would have 1.3/4" thick platforms.
     
  2. CowboyDan

    CowboyDan Member

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    Well ship I would like to ask if you are good welder or not. If you are not good at working with metal then I would not build platforms that way but do it the traditional way.

    Also depending on the area you are in, sometimes it is easier to buy lumber in 8' stick. With metal in order to get it at the lowest price you have to buy it in 20' sticks. Some people do not have the ability (the trailer) to move material that long.

    I started using the tubbing in some of my work because it was cheaper then wood. But the price of metal seems to fluctuate alot in my area.

    However to answer the original question of metal platforms vs. wood platforms. I wood stay with wood. As far as the question of strength, it would depend on the application.
     
  3. Footer

    Footer Senior Team Senior Team Premium Member

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    Even if the welds are perfect, you still will not get the same characteristics due to the amount of bending that occurs in a 1x1 piece of steel. If the platform was built using 2x1 .049 MT1010 that could reduce the bending. Sure you can the platform out of anything you want, but what it all comes down to is you want your Delta Max to be. I don't really feel like busting out the Structural Design for the Stage book (also a GREAT book) and doing a page of calculations... but ya...
     
  4. ship

    ship Senior Team Emeritus Premium Member

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    This was a theoretical question about engineering. Me? not that practiced these days, I do electrics. Welding back in college - I went thru a semester of theater metals/welding class that had it's final exam the same as a normal welding certification, much less nine months at Chicago Scenic Studios in the metals/welding department.

    None the less, this concept of box tubing "as strong as" lumber might be more urban legend such as a HX-600 more powerful than a FEL. The question was first if it's accurate, second in what conditions it would be accurate. The platform concept below was more an example of how this concept wouldn't work as per the overall question of a 1x1 box steel as strong as a 2x4. Let's give an example, as opposed to it being the platform rails... perhaps the platform legs by way of strength?
     
    Last edited: Feb 5, 2007
  5. taylorjacobs

    taylorjacobs Member

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    steel tubing should be as strong if not stronger than 2''x4" as mentioned before the practicality of it is its only downfall. anyone can screw a frame together but not everyone can weld. steel isnt going to split or crak like wood, but u have to use self tapping screws etc. i think the reason it isnt practiced as much is because of the hassle that steel causes
     
  6. jonhirsh

    jonhirsh Active Member

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    Are wenger trouper staging decks made of steel?

    JH
     
  7. Van

    Van CBMod CB Mods Premium Member

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    You know I've used both wood and steel to frame platforms over the years. and I have to say it really dpends on the application. Generally wood platforms are going to be easier to install and assemble. Steel much stronger in "non-standard" configurations. I again agree with footer, although a 1x1 sst will hold the the same static load as a 2x4 it's dynamic characteristics are quite a bit different, it bounces a lot more.
    As for legs, I like steel legs. < I like steel buns better :twisted: > when you have a stock of 6,8,12,16" steel legs with the proper mounting hardware preattached it save a ton of time on installs. Steel legs also don't degrade over time they way 2x4 block legs do, < how many times can you use those same screw holes.> Drawbacks to steel legs, harder to cross brace and box frame.

    Oh and I should take the time to sing the praises of "triscuits" or Stress Skin platform units. I recently began converting our stock over to all triscuits. Do a google of Triscuit platform, so I don't have to explain the entire thing here. If you havedifficulties with your platforms sounding like drums as the actors walk around, < let's face they don't walk around they stomp>, Triscuits just might save you some stress, pun intended.
    I haven't tried the next upgrade yet, foam-core stress skins. Basically imagine laminating a piece of 3/4" plywood on top of and bottom of a piece of 1" polystyrene foam, then being able to load that latform with 400 pounds while being supported by only then ends. Wow.
     
    Last edited: Feb 6, 2007
  8. Footer

    Footer Senior Team Senior Team Premium Member

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    As ship said in the intro, it completely depends on how its used. 1x1 using in any direction will have the same amount of bending. A 2x4 however has 3 different axis that it can be effective at. Its strongest is on edge, and weakest is laying flat. Steel work can make many projects go much faster, and much easier. Decking systems made of steel using 4x4 triscuits are nearly indestructible and have a much larger working load (you can roll genies on them if properly designed). With steel what is around it in a trussing situation or a built up shape make a much bigger difference then the actual steel itself. To me the reason to use steel comes simply down to you know what its going to do, and calculating loads for a steel is much easier and safer then working with wood.
     
  9. ship

    ship Senior Team Emeritus Premium Member

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    Ah' I think we are getting somewhere when it gets to the theoretical side of a simple question presented I had hoped.

    It's not so much a question about specific application, more as a part of a trussed system in being comperable or in a certain direction such as legs where downward force it is thought to be comperable.

    As a 1x1 box steel frame to a platform, it would as noted have lots of bounce to it and require structure or more legs. Thus it might be inferred that horizontally and in the same span, it's not similar or as strong. As a engineered say truss or leg having the same span... perhaps if not stronger.

    Done in the right way... it could replace 2x4.

    Now as the framing members to platforms... 2x3x1/8" thick aluminum I believe I have seen before, is this correct?
     
  10. Footer

    Footer Senior Team Senior Team Premium Member

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    Not to hijack, but I have a drawing of a pretty sweet little triscuit cart that I built awhile back out of a Yaley's book. It holds 10 triscuits vertical and has a pick point, also it takes a forklift very well. I'll dig up the book and post it. Triscuits are the way to go if you want a good stock platform. They weigh alot, but will hold up much better then any 4x8 ever will. Also, the creak is gone, and for a legging system simple stud walls is all you need. Oh, and they store better too!
     

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