Yet another Mega tree question

Discussion in 'Mega, Mini, Spiral & Pixel Trees' started by gnarmstr, Jul 11, 2017.

  1. gnarmstr

    gnarmstr Full Time Elf

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    Just want members thoughts on the following pole.

    I was thinking of Galvanised Steel pole for my future Megatree.

    Inground Galvanised Pipe:
    1m long - Outer Diameter of 60.3mm and Inner Diameter of 51.3mm so a wall thickness of 4.5mm
    with a few bags of concrete holding it in.

    Aboveground Galvanised pipe:
    6.5m (with 1m of it slotted inside the Inground pipe) - Outer Diameter of 48.3mm and Inner Diameter of 41.9mm so a wall thickness of 3.2mm

    Is this an over kill or not strong enough? Would I need guide wires.

    cheers in advance.
     
  2. scamper

    scamper Senior Elf

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    I would say a little overkill on the inground section. I used PVC, when it is concreted in the ground there is no stress on it and at least I will never have a problem with it rusting. I know you say galv, but eventually it will rust especially the stuff you get nowdays.
    PVC is also cheaper and I found a size that was a very snug fir so no movement when in.
    As far as 6.5m... Not sure, Mine is 4.5m and is only around 2mm wall thickness and very strong.
    Actually, that is above ground height, so yours would only be 1m taller, so should be no problem.
    I am no engineer though, so take my advise for just thoughts :thumbsup:
     
  3. OP
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    gnarmstr

    gnarmstr Full Time Elf

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    I never thought of using PVC for the unground part. You haven't had any isssues with it cracking.

    The reason I opted for 4.5mm wall thickness for the inground part is firstly will take a lot longer to rust and secondly allows the pole part to fit in nicely with only a 1.5mm gap around it.

    May see what size PVC I could use. What's the diameter of your pole.

    Cheers
     
  4. scamper

    scamper Senior Elf

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    The PVC is surrounded by concrete and dirt, so no problem with cracking. it's around 50mm (don't have exact size)
    the rusting away is not the problem as it would take many years obviously, but as you are sliding a pole in and out, if you have a cheaper galv or zinc coating on the pipe it will scratch and give somewhere for the rust to start, and as the rust "grows" will create a tighter fit.
    Again, it may never happen, but why take the risk. After all the effort of digging a hole and mixing concrete, I didn't want to do it again.
    **He says as he remembers the pole has moved 3 times :oops:
     
  5. Fing

    Fing Full Time Elf Generous Elf

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    this is my tree, except my in-ground section is only 600mm. I also put some bracing legs, prob overkill but it doesn't move... put the in-ground section lower than the ground level so you can mow over it.
    I used a small section of pipe to hold the sleeve square whilst the concrete set.
    i have some photos in a post on here somewhere...https://auschristmaslighting.com/threads/finally-got-the-mega-tree-planted.7938/
     
  6. scamper

    scamper Senior Elf

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    I forgot to mention that. Mine also is below ground level and I just get the appropriate size pvc cap to put on it in the off season so it doesn't fill up with dirt.
     
  7. ComPeter

    ComPeter New Elf

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    gnarmstr. I have been using a piece of PVC concreted inside a 100 mm piece of PVC which is dug into the ground about 500 mm at dirt level so the grass can grow over it in the off season, with a screwable end cap on the 100 mm PVC. I first thought that it was going to be overkill but I have been able to un-screw the cap for the past 4 years and all is in tip top shape inside (touch wood) year after year, no water ingress, no toads, spiders or worms hibernating in the hole and my tree pole fits in neatly like the day it was new.
     
  8. TByrne

    TByrne Apprentice Elf

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    My post is only 500mm in ground and I use 40x5mm square tube and the post is 5m of 35x3mm. It gets some sway in wind but nothing that will break the pole
     
  9. OP
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    gnarmstr

    gnarmstr Full Time Elf

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    Thanks all, appreciate the info. I think I will go with the PVC pipe in ground as I can use the DN50 Class 18 with male thread so an end cap can be screwed on, which also gives a 1.5mm clearance on the inside that will fit the Gal Pipe perfectly. Due to the 6.5m length of the gal pole I will only be able to go around 600mm into the ground, sounds like this should be ok.

    Now to work out a topper ring, can you even buy just a Gal ring.
     
  10. ComPeter

    ComPeter New Elf

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    Geoff, should mention that I still use guys on my as a precaution against the potentially high winds we occasionally get up here at that time of the year.
     
  11. OP
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    gnarmstr

    gnarmstr Full Time Elf

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    Don't worry I will be using guys, as last Christmas we had 110km/hr winds. Thank god I used stakes for all my props and didn't lose anything.
     
  12. videoman3857

    videoman3857 Full Time Elf

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    Because last year was my first Mega tree and I was uncertain about its location, I made mine
    so it was movable - hence it sits on top of the ground
    I have a Cross foot at the bottom of a 5 mtr gal Pole
    Each cross foot is pegged down with a 600 mm spike hooked over each foot.
    I used 4 guy ropes using synthetic rope. - Set up like ropes on a tent
    The type of rope used tended to slip in the timber tensioners and the rope also stretched in the sun.
    Inspecting the rope a few days ago, I found it to be decaying from the sunlight - despite the manufacturer stating it was UV resistant.
    This year will see the guy ropes replaced with stainless steel cable and turnbuckles.
    Once I am satisfied with the trees location; I think I'll do the hole in the ground trick.
     
  13. videoman3857

    videoman3857 Full Time Elf

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    These guys have painted rings.
    http://www.christmaslightshow.com/mega-trees/mega-tree-parts/hook-heads

    As a foot note to my previous post. I am going through a complete redesign of my Mega tree, though it wont be rebuilt for Christmas 2017
    I found the hardest thing to do was to get the lights on the topper.
    Now I use dumb string lights - 96 strands to be exact and have a 24 hook head screwed to the top of my tree trunk. Getting the strands up there is a task.
    Putting the strands on first and then trying to stand the pole is not an option due to the weight. Last year I used a pool pole with a hook on it to lift one strand of lights at a time. Successful, but cumbersome, time consuming, hard on the neck and blinding in the Qld Sun.
    My new design will do away with the screw head and will use a head that will have bearings fitted opposite each other and will slide up the pole
    with the aid of a winch. If I am lucky enough, I should be able to lathe out the thread and use the existing head.
     
  14. scamper

    scamper Senior Elf

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    So long as you have fairly robust soil to concrete the post in, ie not sand. If you are in sand then at 600mm in the ground with 6m out the top you run the risk of levering the concrete out of the ground. If you can dig deeper and concrete a sleeve deeper, you can always fit a bush to the pole to stop it going in further than ou want and still have the strength in the ground. (Only if it is sandy soil)
    Also, make sure you let your concrete cure for a week before playing with it, so as not to crack the concrete while it is still weak.
     
  15. OP
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    gnarmstr

    gnarmstr Full Time Elf

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    Our soil is clay and rock hard so it should be ok.
     
    scamper likes this.

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