mega tree base ring material ideas....go!

[jchuchla]

I've got a 25' megatree. Last year I used a base ring of 1" PVC. While I was able to bend it into a circle by hand, I found it to be too floppy. The strings pulled too hard on it and it would warp and bend freely as the wind blew. So I want a stronger one that won't warp on the vertical orientation. But I need a material that I'm able to bend into a ring without any specialized forming tools. The circumference is 40' so if I'm doing my math right, that would be about 12.75' in diameter. I'm thinking steel, but open to ideas.

I've heard about using trampoline frames for this, but I've been striking out in local craigslist listings.

So now I'm looking for other ideas.

[mrGrumpy]

Do a spoke and wheel with a dodecagon or a hexadecagon base. I did a 17 foot with an octagon and you do not notice at night. If my 8 is fine a 12 or 16 would be better. Spokes are the trick. 3/4 EMT on the base and 1/2 on the spokes

[lugnut68f]

h t t p s://indianapolis.craigslist.org/for/d/plainfield-pure-fun-12-trampoline/6988447170.html
Only a few hours down I-65 from you. Been posted for about a month so might be able to get it a little cheaper.

[jchuchla]

Do a spoke and wheel with a dodecagon or a hexadecagon base. I did a 17 foot with an octagon and you do not notice at night. If my 8 is fine a 12 or 16 would be better. Spokes are the trick. 3/4 EMT on the base and 1/2 on the spokes

I did have spokes in mine. Only 4 though. Nonetheless, it still bent quite a bit. I can't imagine 3/4 EMT being significantly stronger than 1" PVC. I hadn't considered a non-circle polygon base. That sounds like a lot of skill to get it right. It would need as many sides as I have strings so that the math works out that all the strings are the same length. That's a whole lot of uniform bends.

[jchuchla]

h t t p s://indianapolis.craigslist.org/for/d/plainfield-pure-fun-12-trampoline/6988447170.html
Only a few hours down I-65 from you. Been posted for about a month so might be able to get it a little cheaper.

i'm seeing several in racine Wisconsin too. Both well further than I want to drive for a project like this.

[mrGrumpy]

I did have spokes in mine. Only 4 though. Nonetheless, it still bent quite a bit. I can't imagine 3/4 EMT being significantly stronger than 1" PVC. I hadn't considered a non-circle polygon base. That sounds like a lot of skill to get it right. It would need as many sides as I have strings so that the math works out that all the strings are the same length. That's a whole lot of uniform bends.

No bends. Use 12 or 16 straight pieces with spokes at each joint. You will never see they are not rounded.

[jchuchla]

No bends. Use 12 or 16 straight pieces with spokes at each joint. You will never see they are not rounded.

the tree is 32 strings. So it'd be 32 pieces. But how do you attach the spokes to the straight pieces at the odd angles in the corner joints? and how do you get all those spokes joined in the center?

[mrGrumpy]

Don’t need 32 pieces. Could be done with 8...Octagon. With an octagon, 4 strings per straight piece, you would place a strand at joint, 1/4 way down the straight, 1/2 way down and 3/4 down. Not a perfect circle, but close enough from 10 feet away.

[jchuchla]

It being Friday evening, my brain is too fried to do the actual math, but with a polygon base, the distance between the base vertex and the top ring will be greater than the distance between any other point on the sides and the top ring. So that would require that the strings be different lengths or have tensioners with the ability to make up the length differences. Not impossible, but would require a lot of hardware and adjustment. I've read of people using bungees as tensioners. I tried that initially, but it wasn't anywhere near strong enough for our wind, ice and snow loads, so I switched to stainless wire ties. So if I needed adjustable tensioners, I'd need to be something like turnbuckles.

I'm still not getting the concept how the corners and spokes are joined in your design.

[aknflyer]

I've got a 25' megatree. Last year I used a base ring of 1" PVC. While I was able to bend it into a circle by hand, I found it to be too floppy. The strings pulled too hard on it and it would warp and bend freely as the wind blew. So I want a stronger one that won't warp on the vertical orientation. But I need a material that I'm able to bend into a ring without any specialized forming tools. The circumference is 40' so if I'm doing my math right, that would be about 12.75' in diameter. I'm thinking steel, but open to ideas.

I've heard about using trampoline frames for this, but I've been striking out in local craigslist listings.

So now I'm looking for other ideas.

I found a vey simple solution. Used Cable reels used in the telecom and cable trenching industry. It is square steel in a circle, super solid, it comes in 6' & 8' diameters. I just cut out all the spokes (to lighten it) and drilled a hole on each side, ran conduit across. then drilled one hole 90 degrees to that and put 1/2" conduit to that with a closet flange in the middle. 2 hose clamps to the one crossing the diameter, and a bolt to the 90 degree piece. That centers the closet flange. All conduit was welded to the ring. Then I coated the steel with flexseal, no rust, 3 yrs. The strips hold up the ring with a winch and the ring is bungied to the ground anchors. Kinda makes the strips into guy wires. I did have to add 1 guy rope to the back since my tree is 180 and all the weight is on the front. But keeps the strings very tight and no sagging. If you want less sag, just add a click to the winch.
Contact a local cable vendor, trenching outfit, or telecom company. Mine was free and have 2 rings.
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